Our Facts/Definitions page searches hundreds of reliable dictionaries and encyclopedias.
On our News Resources page you can search individual newspapers (New York Times, Chicago Tribune, etc.) or you can search across many newspapers at one time using the Newspaper Source database. These papers may contain reviews and related articles.
HathiTrust maintains HathiTrust Digital Library. Since 13 October 2008, it preserves and provides access to material scanned by Google, some of the Internet Archive books, and some scanned locally by partner institutions. As of May 2010, it includes about 6 million volumes, over 1 million of which are public domain (at least in the US).
One additional free search tool to consider is Summon (from Princeton). You will see information within books and other materials...but you will not have links to the full text materials.
Finally, you can also perform fulltext searching into thousands of recently published books using the Title Preview option on the ebrary platform.
Here we list some additional web-based resources of interest:
Google Image Search (keywords) -- search for images using keywords.
Google Image Search (image) -- drag and drop an image to start a search
Artstor now offers over 1 million public domain images.