Skip Navigation Bar
IndexCat logo featuring National Institutes of Healths logo, National Library of Medicine logo, a head and shoulders view of John Shaw Billings, and a collection of books.

Boolean and Wildcard Searching


The Boolean operators 'OR', 'NOT', '-', and '+' may be used in your query. Using 'AND' is not necessary as IndexCat™ combines terms with an ‘AND’ by default.

The asterisk '*' can be used as a wildcard character.

Boolean Term

Description

OR

Use 'OR' when you only need at least one of the search words to appear in the results. Example: "surgery OR operation"

NOT or -

Use 'NOT' or '-' when you do not want a particular term to appear in the results. Examples: "heart attack NOT defects" or "heart attack -defects"

*

Use '*' as a wildcard to search on all words that contain the letters you enter. You must enter a minimum of three letters plus the '*' character. Example: "cough*" would find "cough" and "coughs" and "coughing"

+

Use '+' when you require the word to appear in the search results exactly as it was entered.  For multiple words, you must use put a + sign in front of the word that must occur in your search result. Example: search on "+knee surgery" if you only want to retrieve results related to "surgery" of the "knee" and no results with surgery of the "shoulder".

Search IndexCat™ · Help Contents