Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Advanced Search Tips

Return to search


  • Not case sensitive
  • By default, searches for content that contains any of the words entered
  • "" searches exact phrase
  • + requires a word
  • - excludes a word
  • AND operator supported
  • () groups search criteria
  • Word fragments are supported


unmanned aircraft - contains either unmanned or aircraft, content with both increases relevance

"unmanned aircraft"contains exact phrase unmanned aircraft

+unmanned aircraft - must contain unmanned, content that also has aircraft increases relevance

unmanned aircraft -indoor - contains either unmanned or aircraft, excludes content with indoor

unmanne - finds content with unmanned


Note: Including any the following characters in your search words might return unexpected results. If you need to include one of these characters, add a preceding backslash to escape it.
(Example: 1\+1\=2)

+ - = && || > < ! ( ) { } [ ] ^ " ~ * ? : \ /


Created August 31, 2022, Updated September 6, 2022