Boolean Search Operators

You can use the following Boolean search operators to define the relationships between your keywords and narrow or broaden your search results.

When you use multiple operators in your search, they are applied in this order:

1. NOT (-)
2. AND
3. OR

When your search query includes multiple Boolean operators, use brackets " ( )" to help the search engine group them in a way that is relevant for your research:

"badgers" OR "meles meles" AND tuberculosis finds all documents in which the phrase "meles meles" AND the word tuberculosis are both present as well as all documents in which the word badgers  is present.

 (badgers OR "meles meles") AND tuberculosis will only find documents that include the word tuberculosis in addition to either the word badgers  or the phrase "meles meles".

Searching for an exact word or phrase

You can search for an exact word or phrase of two or more words by putting quotation marks around your keywords:

• "mycobacterium bovis" finds articles where those words appear together and in that order.

Using wildcards

A question mark (?) can be used to replace a single character in a word. Use an asterisk (*) to replace zero or more characters in a word. 

• wom?n finds woman or the word women.
• behavi*r finds behaviour and  behavior.

Truncation

An asterisk (*) can also be used at the end of a word to find multiple endings of that word.

• vaccin* finds articles with the words vaccine, vaccines, vaccinated and vaccination

Author search

Put quotation marks around an author name to find that exact author.

• "John Smith" finds articles by John Smith, John K Smith and John Colby-Smith.
• "J Smith" finds articles by J Smith, JR Smith, John Smith and Julie Smith.