The Literature Searching guide shows you how to complete an effective literature search from beginning to end. Use the tabs at the top of the page to navigate through the guide.
Remember: the Library team provides a range of research support services to Monash Health employees and students. Attend a live webinar, book a research consultation, or request a literature search and get in touch with the Library team if you have any questions.
After refining your clinical/research question, the next step is to identify related search terms and synonyms that represent each main concept. While doing this, be careful not to introduce irrelevant terms or go beyond the scope of the search question. An effective literature search combines both keywords and subject headings for each main concept.
Note: This is an iterative process, as you find relevant articles, you will discover additional search terms.. A chart or table can be useful to keep track of search terms.
Is there a difference between keywords and subject headings?
Yes! Keywords are the natural language terms and phrases used to describe search concepts. Subject headings are "controlled language" words used by databases to ensure that all items relevant to a particular topic will be found. Searching with subject headings is a consistent and precise way to search many databases. However, it is not as flexible as a keyword search because you must know the exact term to use.
Should l use keywords or subject headings in my search?
Both! An effective literature search combines keywords and subject headings for each main concept.
Search Tip: Use keywords as a jumping off point to find corresponding and relevant subject headings for the databases that you are searching on. Remember to keep track of keywords and subject headings used in your search.
Keywords are the natural language terms that you type into a database, such as Medline, or a search engine, such as Google. Keywords are the terms found in places such as the title, abstract, and author provided keywords. The database will word-match your keywords against fields such as these and deliver results that match your keywords.
Not all authors use the same terminology, so try to think of the different ways that authors might express the concepts for which you are searching. This will ensure you capture all relevant articles. Some things to consider:
Alternate spelling |
pediatric or paediatric |
Alternate ending |
hospital or hospitalised or hospitalisation (or hospitalization) |
Word form |
physiotherapy or physio therapy |
Plural form |
child or children, woman or women |
Acronym |
Severe Acute Respiratory Syndrome or SARS |
Abbreviation |
electronic cigarettes or e-cigarettes |
Terms that mean the same thing |
Cancer or neoplasms or tumour or tumor or carcinoma |
Subject headings come from an established or controlled list of vocabulary and are assigned as ‘indexed terms’ to articles as they are added to medical databases. Subject headings bring uniformity and consistency to searches by using the same terminology for search terms, regardless of the language used by authors within individual studies.
Subject headings that you may be familiar with are MeSH (Medical Subject Headings) terms used in Medline and PubMed, and Emtree terms used in Embase. It is important to check the subject headings in the controlled vocabulary of each database you chose as not all databases use the same headings.
For example, if one of your main search concepts is ‘complementary medicine’
Search for MeSH subject headings that relate to your keywords.
Visit our overview of health databases to see a full list of databases and corresponding subject headings.
3 minute guide to subject headings (2013), Leeds University Library
Some ways to identify synonyms of keywords and subject headings:
Quick links
Text mining can help identify how often terms come up in the literature and help identify keywords and subject headings that are relevant to your search concepts. Text mining tools are usually free and offer a quick way to find synonyms and fill gaps in your search.
Text Mining tools
Locate synonyms by analysing word frequency or extracting keywords and subject headings used within an article.
Visualisation tools
Create word clouds and visual based graphics related to search terms.
Visit the Text Mining page in the library’s Research Toolkit for more information and a list of helpful tools.
Boolean operators are used to group and combine search terms. They are the most effective tool we have for searching databases because they turn complex search queries, with multiple concepts, into something the database can understand.
Combining search terms
Two small words -- AND and OR -- are arguably the most common and powerful Boolean operators.
Note: When used within a single search line, both AND and OR should be used to connect related themes or synonymous words, e.g. high blood pressure OR hypertension OR cardiovascular disease.
Grouping search terms
Parentheses (round brackets) are used to group together multiple search terms or concepts. Round brackets enclose distinct sections of the search, such as related terms combined with the OR operator.
For example: (cancer OR neoplasm) AND (therapy OR treatment)
You are encouraged to document your search methodology. This helps structure your research and keep it on track. Record where you are searching, search terms being included (and excluded), your database search strategy and key references.
Create a concept map or table with a list of your main concepts (developed from your PICO), and keywords and subject headings that you have identified. It can be helpful to use a Word document table or an Excel spreadsheet.
You should start your list during the background research stage and add and adapt as you move through the literature searching process.
Note: Not all databases use the same subject headings, so you may need to include multiple lists of subject headings when searching across multiple databases.
Recording where you search
Document your search process to show and be reminded of how you located search results. This can be outlined during the planning stage and is particularly helpful when working on research projects over a long period of time.
Use headings such as these:
Save a copy of your search in the database that you are using. Having a search history ensures that you don’t have to repeat work and allows editing as your search progresses. You can create free accounts in many databases using your Monash Health employee login details. Visit the 'Working with Results' page for more information on saving your search in a database.
Export search results to a safe place to ensure that you don't misplace references, or forget where and how you found relevant references. Use reference management software such as EndNote. This helps you store, organize and retrieve search results quickly with options of attaching full text pdfs. Visit the 'Working with Results' page for more information on exporting results and managing references.
Grey literature is an essential consideration in systematic and thorough searching. It encompasses government reports and policies, conference presentations and papers, issues papers and white papers, research and industry reports, theses and dissertations, trial data, statistics and surveys.
Use this template to keep track of relevant results from your grey literature search.
Visit the Grey Literature guide for more information on where top find grey literature and search tips.
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