Databases
Google Scholar provides a simple way to broadly search for scholarly literature. You can search across many disciplines and sources: articles, books, abstracts, court opinions, academic publishers, professional societies, online repositories, universities, and other websites.
The Smithsonian Libraries have a collection of research, databases, e-journals, and digital collections.
The Library of Congress is the largest library in the world, with millions of books, recordings, photographs, newspapers, maps and manuscripts in its collections.