Here are a few ways to search for content on the Deep Web:
Federated search of selected business sources, sites, databases
data, including raw data & interactive data in multiple formats, from US government sources
govinfo provides free public access to official publications from all three branches of the Federal Government.
Grey Literature Network Service. Grey literature deals with multiple document types produced at all levels of government, academics, business, and organization not controlled by commercial publishing.
Texts, audio, moving images, and software as well as archived web pages. The Wayback Machine often provides access to otherwise expired web pages.
Grey literature from Europe
"SSRN´s eLibrary provides 777,769 research papers from 360,827 researchers across 30 disciplines."
Focus on engineering, math and computing.
subscription databases paid for by the UW Libraries. search these to find articles published in journals, magazines, newspapers, trade publications, as well as data, government publications and more
Catalog of the holdings of libraries around the world.