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East and North Hertfordshire NHS Trust Knowledge and Library Services: Boolean Operators AND OR NOT

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What are Boolean Operators

 

Boolean operators 

  • are linking words, (e.g. AND OR NOT)
  • they enable you to combine different keywords when searching a database or using a search engine 
  • they enable you to refine your search so you retrieve fewer, more relevant results.

For more information view the short video or the pdf version of the video linked in the boxes below.

AND OR NOT 

Boolean Logic - short video. Best viewed in full screen

Boolean Logic - Printable Version

Boolean Operators - Tutorial