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Evidence Based Literature Searching: Search tips


Here are some basic search tips that work on virtually every database.

Questions to consider before searching

  • What is the most important piece(s) of this search? (i.e. what must be in an article for it to be a relevant search result?)
  • Are there any other ways to describe this concept? (identify possibly synonyms and/or subject terms)
  • What type of resource is best to answer this question and where should I search first?

Google Scholar search strategies

When searching Google Scholar it is important to use if effectively.
The appendix from the book Googlepedia® by Michael Miller,  3rd ed, 2008
 has some excellent tips.


Here are some basic search tips to target better articles:

  • Search each concept separately and build one at a time
  • Think of synonyms for the words that you choose when create your PICO
  • Try to choose a relevant database (e.g. Scopus-biomedical and life sciences)
  • Try several databases, not just one
  • Use Boolean Operators

    AND means both terms must be present (this will narrow your search)
    OR means either term as well as both terms are present (this will broaden your search)
    NOT means one term must not be present

  • Use Controlled Vocabulary also known as MeSH (Medical Subject Headings) in PubMed or Subject Headings-these are terms naming descriptors in a hierarchical structure
  • Use Natural Language-the searcher's own words
  • Combine  Controlled Vocabulary and Natural Language to broaden your search
  • Try Focus (sometimes called Main Concept)-tells the database to retrieve only those articles in which your subject term is considered to be the primary focus of the article.
  • Try Explode-tells the database to search for your requested subject heading as well as any more specific terms that are related to your subject heading
  • Use Limits-limiting by publication date, English language and/or age groups will help narrow down a search
  • Gold mine- is a term that really means you are looking everywhere for “gold”, getting into the material further and pulling more information from what you have found.
       Check the bibliography of a good article for more references
       Look for new articles that cite a good article from more references
       Look for more articles written by the authors
       If the database offers related citations or related article, use this as they try to match your search terms found in the good article

Are any of your results relevant? Refining your Search

If yes, look for clues to help continue your search:

  • Are there subjects assigned that look helpful? Try searching them.
  • Consider "find similar" suggestions if available.

If no, did you find too many results?  Too few?

  • Re-examine your question/topic - is it too specific? Too broad?
  • Think about the search terms that you are using - consider subject terms or different synonyms
  • Think about the database(s) that you are using
  • Consult a colleague and/or librarian for suggestions about terms and databases to try - we all have different biases and experiences to draw on, might need a new perspective
  • Consider the fact that the evidence might not exist! 

Doesn’t exist is a hard concept to grasp in this age of technology! It might also mean that it is not available in the places/resources you are searching (Proprietary, not well funded research topic, positive publication bias, etc.)

Strategies to Expand Your Search

This handout includes strategies including checking references, checking point of care tools, cited reference searching, and PubMed's similar articles feature.

PubMed For Nurses Tutorial

The PubMed for Nurses Online Training is a 30 minute self guided tutorial that is targeted toward nurses but is helpful for anyone who would like to learn about literature searching in Pubmed.  This tutorial includes modules on simple searching, using filters, using PubMed Clinical Queries, and My NCBI.