Searches are not case sensitive. san_francisco works too.

Different subjects can be searched at once if the OR option is set.
Examples: Statue_of_Liberty Grand_Canyon Golden_Gate_Bridge

Searches are for precise matches of the words you enter.
Examples: Air finds air not hair or airplane; man does not find woman.

Start search words with three periods to find words ending with specific letters.
Examples: ...man finds man as well as woman, Amman and human.

End search words with three periods to find words starting with specific letters.
Examples: man... finds man as well as mankind, manifold and manatee.

Sandwich search words with three periods to find words containing specific letters.
Examples: ...man... finds man plus commander, penmanship and Germany.