BIOL 1510 Biology II: Keywords & Boolean Operators

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Searching in Databases

A database's search engine does not work just like Google. 


This means that you cannot type your entire research question/topic in the search box.  Instead, you must pull out the keywords that describe your topic and use only those keywords (or related terms).  Here's a short video on how to find the keywords of a research topic:

Boolean Operators

Combining Your Keywords with Boolean Operators

Once you find your keywords, you then have to indicate the relationship between the keywords using Boolean operators AND, OR, or NOT.



  • AND finds results that contain all of the keywords
  • AND finds less results and helps narrow your search
  • Example Search: Strawberry AND Vanilla AND Chocolate will find results that contain all three flavors




  • OR finds results that contain at least one of the keywords (but not necessarily all)
  • OR finds more results and helps broaden your search (when you are not finding enough)
  • Example Search: Strawberry OR Chocolate OR Vanilla will find results that contain at least one of those flavors 





  • NOT excludes keywords from the results
  • NOT narrows your search but should be used cautiously to avoid accidental exclusions
  • Example Search: (Strawberry OR Vanilla) NOT Chocolate will find results Strawberry and/or Vanilla but excludes any results that mention Chocolate

(adapted from content created by Helen Hooper, Sharon Bryan, and Kylie Bartlett of James Cook University -- Writing Guide)