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Literature Searching in Six Simple (ish) Steps
💡 No need to be daunted - just work through each of the steps methodically🔎 Each of the six search steps will have an example (look for the 🔎 icon)
✅ While presented as a linear process, the reality is that you will be jumping back and forth as it is an iterative process
😓 If confusing or taking too long, the Library is happy to provide advice for any stage
Jump to:
Step 1: Choose databases to search
Step 2: Identify concepts
Step 3: Use keywords & subject headings
Step 4: Apply Limits
Step 5: Use citation searching tools
Step 6: Use other tools as required
Top 🔼Step 1. Choose which databases to search for your topic
A. This choice will generally depend on:
a) The search topic itself
b) How extensive the search needs to be (e.g. a systematic review will require many databases, whilst finding articles for a presentation may just require one)c) Which databases are accessible to you
B. The Library Databases page lists around 30 database, many of which are quite specialised.
C. Below are the major databases available to Peninsula Health for broad speciality areas:
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Medicine: Medline, Embase
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Nursing: Emcare (medicine databases could also be considered due to their much larger size & broad coverage)
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Allied Health: Emcare, specialist Allied Health databases (as listed on the Database page)
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Mental Health / Psychology / Psychiatry: PsychInfo (medicine databases could also be considered)
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Other: The Library Databases page has many additional databases which cover specific subjects
D. 🔎 Step 1 Search Example
The simple example search question is: What is the effect of exercise on depression?
For this topic, you might choose Medline & Embase, as they are both large medical databases. PsychInfo could also be considered given that it covers mental health, psychology.
Top 🔼Step 2. Identify the main concepts in your search topic
A. It's important that your search topic question is structured well. It needs to:
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Clearly show what your are trying to find
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Not be too broad (as this will result in too many results) & conversely not overly specific (as this will result in too few or no results)
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Most searches will have 2 - 5 concepts involved
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There are quite a few search aids available, of which PICO is the most well known
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PICO stands for: Population or Patient or Problem | Intervention or Indicator | Comparison or Control | Outcome
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PICO works well for some questions, but not for others. Use it if helpful, ignore if not (it is meant as an aid, not a requirement)
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View additional search aids (scroll down to Explore common frameworks section)
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B. 🔎 Step 2 Search Example
The simple research question "Does exercise improve depression? has two just concepts - exercise and depression
(you may wonder why "improve" is not a separate concept? Any article about exercise and depression will relate these two topics to each other so will be there implicitly anyway)
Top 🔼Step 3. Use both keywords & subject headings, for each concept
A. Background
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An article record in a database is generally not the full text of the article, but instead a small amount of information about the article (e.g. title, abstract etc)
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The article record is comprised of two types of information:
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Information inherent to the article (title, author, journal, year etc) - this is the information targeted by keyword searching
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Information added to the article (subject headings to make it more structured and retrievable) - this is the information targeted by subject heading searches
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Keyword and subject heading searches both have their strengths and weaknesses, which is why it is generally best practice to include both in the search strategy where possible
B. Keywords-
As per Background above, keyword searching targets the content that comes with the article (things like title, abstract and so on)
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👉 Because authors can describe a given concept in many different ways, keywords searches have to try a capture this variability.
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Due to this you need to consider:
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Potential synonyms (e.g. exercise, exercising, physical activity, physical activities, walk, walking etc)
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Alternative spellings (e.g. labor, labour)
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Abbreviations / acronyms (e.g. cvd for cardiovascular disease)
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C. 🔎 Step 3 Search Example: KeywordsConsidering the above points, the first concept (exercise) might be expressed as a keyword search like:
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exercis* or physical activit*
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The asterisk at the end of exercis* will find any extensions of that (e.g. exercise or exercised or exercising)
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Use of the word "or" tells the database that articles with either of these terms are acceptable
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Phrases (like physical activity) are automatic; you don't need quotes i.e. "physical activity"
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It's easy to see that this search won't catch all forms of physical activity
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for example it won't find articles use terms like have running, walking, sports etc instead of the terms above
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this is where subject headings come into their own as below
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You can also specify the fields where the words have to appear. In the example below, you are saying the keywords have to be in either the title (ti) or abstract (ab)
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(exercis* or physical activit*).ti,ab
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D. Subject headings:
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Subject headings aim to solve the problem described above in keyword searching; i.e. that a given concept can often be described in multiple ways
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Instead - for a given concept - a single subject heading is used consistently for this concept across the entire database so all you need to do is find the one appropriate subject heading
E. 🔎 Step 3 Search Example: Subject headings (5 steps)
1. Search for subject heading
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In this example, going to search to see if there is a good subject heading for the concept exercise
- For a subject heading search, the Map Term to Subject Heading box must be selected
2. View subject heading search results
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In this example, there is a good subject heading available (ie Exercise)
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They won't always match in this way. For example, if you search for vitamin c, the matching subject heading is Ascorbic Acid
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Optional I. You can click on the Scope on the right to see more information about the subject heading. This can also be useful for finding keyword synonyms
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Optional II. You can click on the subject heading itself (ie Exercise) to see where it fits in the subject hierarchy. Will do this in this example as shown at step 3
3. Subject heading hierarchy / Explode / Focus
- This is the screen that results from clicking on a subject heading and then scrolling down to the blue line
- It shows how the subject heading (Exercise) fits in the greater subject hierarchy
- The number in the blue line indicates how many articles will be retrieved for that subject heading
- It is not always the case, but here there are narrower terms under the Exercise subject heading (this is apparent as they are indented relative to Exercise)
- Some of these narrower terms themselves have narrower terms as indicated by the + icon (the running one has already been expanded)
- By ticking the indicated checkbox to the right of the results number, we are telling the database that we also want to include all of these narrower terms in the search as well. This is called exploding a subject heading
- As well as narrower terms, this view also shows broader terms (in this example Motor Activity and Locomotion are broader terms). Sometimes on viewing this, you may decide a broader term is more appropriate
- The checkbox to the right of the Explode checkbox is the Focus checkbox. This can be selected to tell the database that resulting articles need to be focused on the subject heading rather than just being a minor aspect
- After viewing the subject heading in the hierarchy and deciding whether to explode or not (as available), then scroll back to the top of the page and click on the Continue button
4. Subheadings
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The subsequent screen will show subheadings related to the subject heading
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Depending on the search, these can be quite useful. For instance, if you were interested in the immunological aspects of exercise then you would tick the Immunology subheading
- You can choose to select none, some or all subheadings. In this example, selecting none so just clicking on the Continue button
5. Results page
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Now back on the results page with the number of records indicated
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exp indicates subject heading explosion whereas the forward slash indicates that Exercise is a subject heading
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👉 subject headings vary by database, so you need to follow this process in each new database to find the appropriate subject heading
The short video (3 min) demonstrates some of these ideas
F. Putting it all together
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For each concept in your search, develop keywords and subject heading/s (where available)
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Then for each concept, do the keyword search, then the subject heading search, and then combine both searches with OR to produce a set of results for that concept
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Once you have done this for all concepts, combine them all by AND for your final set of results
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As per the example below
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The first search was keywords for the exercise concept
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The second search was the subject heading for the exercise concept
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The third search combined searches 1 and 2 by selecting their check boxes and then clicking on the OR button below. Search 3 is now the "exercise" set of results
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The same process was repeated for the second concept of depression (searches 4-6) with search 6 being the "depression" set of results
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The final search 7 combines the "exercise" set (search 3) with the "depression" set (search 6) by selecting their check boxes, then clicking the AND button below
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Top 🔼Step 4. Apply Limits
As per the first three steps, you now have a set of results. This can be further refined however by applying relevant limits
There are many limits available but some common ones include language (e.g. English), publication years (e.g. 2015-2025), publication type (e.g. review, meta analysis)
Generally, you apply limits at the end of a search
🔎 Step 4 Search Example
Limits were applied to the 33547 results from the example at Step 3
This was done by clicking on the caret as indicated by the top red arrow below to reveal the Limit options
English language, last 5 years, all Adults and Review articles were selected and then applied to the search by clicking on the blue Search button
This reduced the results down to around 100 results from approx 33 K
Note - additional limits are available in Medline via the button indicated by the bottom red arrow
Note - there is a Humans limit to exclude animal studies. As this is actually a subject heading, just be aware that selecting this might exclude the very latest studies which haven't had subject headings applied as yet
Top 🔼Step 5. Use Citation searching tools
So far the searching has just involved using databases such as Medline, Embase etcHowever, it can be well worthwhile to complement this approach to retrieving relevant articles by also using citation searching
This is because they work in completely different ways and so you will retrieve unique articles with each approach
There are two basic approaches to citation searching which is forward and backwards citation searching
1. Forwards citation searching is just finding which articles have subsequently cited an article of interest. This can be achieved by:
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Pasting an article title directly into Google Scholar and then clicking on the Cited By link
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If an article is recent, then there may not be any Cited By link available
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Articles revealed by clicking on Cited By themselves may have Cited By links so it is possible to discover a whole network of citation articles
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Using Cited By in Google Scholar is particularly useful when your seed article is very relevant to your search topic
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Finding your seed article in Discovery and then clicking on the Cited By in Google Scholar link below the article
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Using alternative tools such as Scopus or Web of Science if you have access to them
2. Backwards citation searching is examining which articles your article of interest has referenced in its bibliography. This can be achieved by:
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Searching for the seed article in Discovery, clicking on the title of the article and then scrolling down to citations
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Where available, this will show the article references and they will either be available immediately in full text or can be requested
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This is not available for all articles in Discovery
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Manual inspecting the references from the PDF, PubMed etc
🔎 Step 5 Search Example
In this example, we have found a relevant article by searching in Medline and now wish to see what other articles have subsequently cited it (as they are likely related)
Have done this by searching Google Scholar with the DOI of the article - this is the number that starts with 10.
Can see that the article of interest has been cited by 10 more recent articles
Clicking on Cited by 10 will reveal those 10 articles; and they in turn may have been cited by others
On the right is a link to the full text via Peninsula Health Library. Such links are enabled by using the custom Google Scholar link as below
https://scholar.google.com/scholar?&inst=17914897140506615607
If a seed article is particularly relevant, then it can be worthwhile clicking on the Related articles link also
Top 🔼Step 6. Use other tools as required
Generally, database searching and citation searching will find relevant articles. Sometimes however additional tools can be used to find relevant articles and / or find good search keywords
1. Undermind
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Performs deep research using natural language prompts
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They system will ask you questions to help refine the search question
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Takes a while (10-15 min) to complete
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👉 not accessible on the Peninsula Health network
2. Other AI search tools
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Genspark.ai
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ScienceOS
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SciSpace
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✅ all currently accessible on the Peninsula Health network
3. CitationTree
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Search with the DOI (number starting with 10.) of a relevant seed article
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It will display a graph of related article titles
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Click on any article title to go to the homepage for that article; alternatively export all using options at bottom left
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Useful when you have a relevant seed article and want to find more related articles
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