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Master of Science in Biomedical Communications

Build Your Search Using Boolean Logic

Boolean Logic

Boolean logic is the fancy way you search research databases use to search. It's required in research databases and will make your Google searching stronger. 

Boolean operators connect your keywords together. The three basic boolean operators are: AND, and OR. You also use "quotation marks."


AND links together new aspects of your topic. It tells the database that all the search terms must be present in the results.

For example: (cloning AND ethics AND humans) would bring in results like the diagram below. 


OR links together related terms. It will bring in more search results.

For example: you might be interested in ("global warming" OR "climate change").


Use quotation marks when you want to tell the database to search a phrase.

For example: (UTM OR "University of Toronto Mississauga").


Use NOT in a search to:

  • exclude words from your search
  • narrow your search, telling the database to ignore concepts that may be implied by your search terms
  • example:  cloning NOT sheep


Use truncation to broaden your search. E.g. 'prevent*' will find 'prevent', 'preventing', 'prevention', 'preventative', 'prevented' etc.


Use wildcards to substitute a symbol for a single letter of a word. E.g. Immuni?ation



*This page was adapted from Stephanie Perpick's MGTA35 Guide.