The University of Kansas Libraries
The Deep and Hidden Web
Internet Search Engine Groupings
Search engines which index the so called "deep" or "hidden" Web search out Web pages which may not normally be found though regular major search engines. Material of this type may include searchable PDF files, company intranet sites, digital tables of contents and searchable, but proprietary, databases. You may also find the elusive conference paper in one of these search engines.
Complete Planet searches across 70,00 searchable databases and specialty search engines.
Hosted by the University of California, Infomine is a search engine which specializes in scholarly databases.