Sign 1). "words"
Searches for the exact phrase not each of the words separately.
Sign 2). -words
Excludes this term from the search.
Sign 3). ~words
Will also search related words.
Will also search related words.
Sign 4). site:website address
Only Search the pages of that site.
Sign 5). filetype: filetype
Searches only results of the file type you designated.
Sign 6). intitle: titles
Only Show results withthat word in the title.
Only Show results withthat word in the title.
Sign 7). year-month-date..year-month-date
Shows all results from within the designated time range.
Sign 8).author: author
For more specific results, you can put the authors full name of initials in quotes.
Sign 9).define: words
Search the definition of the words quickly.
Source: Mashable