This page will bring together the best known resources, with tips on how to use them for this purpose. Plus signs are only useful when the word is a very-common 'stopword'. A huge database, very fast, very simple. AltaVista AV's database is about the same size as AllThe Web's, but it allows much more specific searching via special keywords. Recognizes doublequotes, periods, plus, minus.
Full form offers date options, etc.
Recognizes doublequotes, periods, plus, minus. See also the overview of the hundreds of pages of original content offered here, and the offer for a printed version of the site.