Some advanced search operators for Google Docs

Type of document – type:{spreadsheet,presentation,document}

Phrase (use quotes) – e.g. “drive the car”

Exclusion of an item (use the minus sign) – e.g. white socks -baseball

Time of item editing – before:YYYY-MM-DD, after:YYYY-MM-DD

Ownership of items –

Hidden or starred items – is:starred, is:hidden

Items shared with others or shared with you –,

By subject (or word in subject) – subject:INSERTSUBJECTHERE

By title (or word in title) – title: INSERTITLEHERE

Either-or function – e.g. bison OR buffalo

These operators are entered into the search box on your Google Docs page. You can sometimes string these functions together. For example, if you wanted to find a file you have that was made last year, shared with your boss, and was about sports, you could enter: before:2010-01-01 subject:sports.

via File-Finding in Google Docs: Advanced Search Operators.