Google 's search engine normally accepts queries as a simple text , and breaks up the user 's text into a sequence of search terms , which will usually be words that are to occur in the results , but one can also use Boolean operators , such as : quotations marks ( '' ) for a phrase , a prefix such as '' + '' , '' - '' for qualified terms ( no longer valid , the ' + ' was removed from Google on October 19 , 2011 ) , or one of several advanced operators , such as `` site : '' .
Google 's search engine normally accepts queries as a simple text , and breaks up the user 's text into a sequence of search terms , which will usually be words that are to occur in the results , but one can also use Boolean operators , such as : quotations marks ( '' ) for a phrase , a prefix such as '' + '' , '' - '' for qualified terms , or one of several advanced operators , such as `` site : '' .