Remember to consider government information when doing your research. Government websites have useful overviews, reports, data, studies, documents, etc. Check out the Government Information and the Public Policy guides.
A federated search engine from the Government Publishing Office searches multiple US federal government databases, retrieving reports, articles, and citations while providing direct links to selected resources available online.
Provides indexing and open access to a collection of more than two million historical and current government technical reports archived by the National Technical Information Service (NTIS). Over 500,000 documents are available in full-text format.
Comprehensive summary of statistics on the social, political, and economic conditions of the United States, from 2013 to the present. Volumes covering 1879-2012 are on the US Census site.