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The EBM Medical Literature Search: Boolean Operators

FAU Medical Library

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Boolean Operator: AND


Use "AND" to link two terms together, this narrows your results. Articles will contain both and omit the pieces that only have one term or the other.

When you start to nest Boolean terms, AND is seen as the primary operator, and will be factored before OR and NOT. 

Boolean Operator: OR


Use "OR" to look for articles that contain both words. This broadens your results. Articles will contain either term or both terms. 


Boolean Operator: NOT


Use "NOT" to look for articles that do not contain a specific word. This narrows your results. Articles will only contain one word and omit the pieces that contain the undesired word. 

TIP: Using NOT may negatively effect your results, as it ignores all articles with the undesired word. This operator is best used after you have gained some familiarity with the literature and notice a topic trend you wish to ignore, or if you already know you do not wish to look at a particular portion of the literature. I.e "typhoid fever" NOT children; or  Zika virus NOT (pregnant or pregnancy).