Definitions from GPO:
The Government Publishing Office's govinfo.gov is the major online source for relatively recent hearings.
Hearings and Prints may be available through individual Committee web sites, which can be found by chamber:
Unfortunately, some Congressional Committees do not release their hearings to GPO. Many of them, however, are still available on the Committees' websites. For House hearings, you can also check this source:
Databases
A librarian at the Univ. of Kansas libraries has a great guide full of links to Congressional Hearings on topics of current interest, as well as general information about Hearings:
Here are two handy reference lists giving online hearings sources (complete with dates of coverage), from the Law Librarians Society of Washington, D.C., and the Georgetown Law Library. Note that some sources linked in these resources are not freely available.
Notes regarding formats: Hearings and Prints are usually available in either text or PDF format.Text files do not display charts, photographs, and other graphic materials. The PDF files are electronic copies of the full hearing, including both transcripts and illustrative material, reproduced in the same quality as the printed documents.
Occasionally, not all exhibits brought to Committee hearings will appear in the printed or digital versions of the hearing transcripts. You might be able to find this material on majority or minority websites. See the links to Committees below.
Official Committee web pages, especially in the House, are operated by the jajority party, but the minority party also maintains a site for the Committee. Particularly when looking for information on controversial topics, it would be wise to seek views on both websites. Each will have a link to the other, somewhere in its navigation.
Two databases available to St. Mary's students, faculty, and staff also include Hearings and Prints. In MasterFile Premier, limit your search to "Primary Source Documents" to find hearing testimony, as well as other government publications. The database breaks each hearing into individual chunks of testimony is a nice feature.