Boolean searching, i.e. using Boolean Operators in between your search words, is the single most effective 'advanced' search technique you can use to improve your search results, making them more relevant and precise. They connect your search words together to either narrow or broaden your set of results. The three basic boolean operators are: AND, OR, and NOT
Boolean operators that help you narrow your results:
Boolean operators that help you broaden your results:
Use AND in a search to:
The purple triangle in the middle of the Venn diagram below represents the result set for this search. It is a small set using AND, the combination of all three search words.
Be aware: In many, but not all, databases, the AND is implied.
From a single search bar:
Use OR in a search to:
All three circles represent the result set for this search. It is a big set because any of those words are valid using the OR operator.
Use NOT in a search to:
From a database's advanced search interface: