Additional help

Phrase search ("")
By putting double quotes around a set of words, you are telling Google to consider the exact words in that exact order without any change. Google already uses the order and the fact that the words are together as a very strong signal and will stray from it only for a good reason, so quotes are usually unnecessary. By insisting on phrase search you might be missing good results accidentally. For example, a search for[ "Alexander Bell" ] (with quotes) will miss the pages that refer to Alexander G. Bell.

Terms you want to exclude (-)
Attaching a minus sign immediately before a word indicates that you do not want pages that contain this word to appear in your results. The minus sign should appear immediately before the word and should be preceded with a space. For example, in the query [ anti-virus software ], the minus sign is used as a hyphen and will not be interpreted as an exclusion symbol; whereas the query[ anti-virus -software ] will search for the words 'anti-virus' but exclude references to software. You can exclude as many words as you want by using the - sign in front of all of them, for example[ jaguar -cars -football -os ]. The - sign can be used to exclude more than just words. For example, place a hyphen before the 'site:' operator (without a space) to exclude a specific site from your search results.

The OR operator
Google's default behavior is to consider all the words in a search. If you want to specifically allow either one of several words, you can use the OR operator (note that you have to type 'OR' in ALL CAPS). For example, [ San Francisco Giants 2004 OR 2005 ] will give you results about either one of these years, whereas [ San Francisco Giants 2004 2005 ] (without the OR) will show pages that include both years on the same page. The symbol | can be substituted for OR. (The AND operator, by the way, is the default, so it is not needed.)