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Searching the Literature: The Basics

Learn how to effectively search the literature with tips on asking questions, selecting resources, and developing search terms.

Execute the Search

You've identified search terms for each of your concepts.

It's now time to enter your search terms into the search resource and generate some results.

Search Tips - Keywords

"Phrase Searching"

Use quotation marks to ensure that a keyword phrase is searched as a whole (vs. searched as individual words).

  • "quitting smoking" rather than quitting smoking
  • "nicotine replacement products" rather than nicotine replacement products


Use an asterisk (*) to search for multiple forms of a keyword using the same root.

  • smok* returns smoke, smoker, smokers, smoking, etc.
  • "high school*" returns "high school", "high schools", "high schooler", "high school students", etc.

Search Tips - Subject Headings


Subject headings in most databases are arranged in a hierarchy of broader and narrower terms.  Exploding a subject heading means searching for results tagged with a particular subject heading as well as all of its narrower subject headings. 

  • In Medline, exploding the subject term Tobacco Smoking also searches for results tagged with its narrower subject headings Cigar Smoking and Cigarette Smoking
  • In CINAHL, exploding the subject term  Tobacco Use Cessation Products also searches for results tagged with its narrower subject headings Electronic Cigarettes and Nicotine Patch.

Focus/Major Heading

Some databases allow you narrow your subject heading search to only return results in which the selected subject heading has been identified as the main focus of the article.

  • In Medline, selecting the Focus checkbox next to the subject term Cigarette Smoking will only return results in which Cigarette Smoking is the primary focus of the article.
  • In CINAHL, selecting the Major Heading checkbox next to the subject term Nicotine Patch will only return results in which Nicotine Patch is the primary focus of the article.


Remember: Not all search tools use Subject Headings to describe content.  In these cases, searching with keywords alone is sufficient.

Combining Search Terms

At this point, you've generated a variety of search terms (both keywords and subject headings) to represent your key concepts.  Now it's time to combine these search terms into a search strategy.

Search terms can be combined using AND or OR.  OR is used to combine terms representing a single key concept, while AND is used to bring together multiple concepts.

Venn diagram illustrating the combination of key concepts using AND and OR

Database Tutorials

For a detailed explanation of how to apply these tips and strategies to specific databases, check out HSL's database tutorial videos: