The Congressional Research Service (CRS) is responsible for the research, analysis, and information that Congress needs to make informed decisions. CRS Reports are available on a wide variety of topics, but they are not yet available to the public in a comprehensive way. I have linked to sources for CRS reports below. It may be helpful for you to view some of these policy reports to:
Proquest Congressional Publications allows you to search for CRS Reports from 1916 – 2003.
The National Council for Science and the Environment collects CRS Reports on environmental and related topics.
Open CRS attempts to collect and maintain CRS Reports in a central, open repository. Searching and browsing the reports in Open CRS requires an easy-to-create account (user name, password, name, organization).
If you're interested in additional information about CRS and CRS Reports, Deborah Liptack wrote an easy-to-read article for the publication "Online." (Liptak, D. (2005). CONGRESSIONAL RESEARCH Service Reports Revealed. Online, 29(6), 23-26. Retrieved from Academic Search Complete database.)