Extensive database of Congressional materials, 1789-present. Much, but not all, full text.
Interface has recently changed.
"Congressional Publications" search now includes entire period 1789-present and includes Serials Set (vast collection of Presidential communications to Congress, treaty materials and executive agency and departmental reports ordered to be printed by Congress; some bills and resolutions, committee prints and heaings, Congresisonal Record debates, 1789-1969).
Basic Search searches only metadata, not full text! Use Advanced Search to search full text of documents.
Always check left column of search screen and document categories underneath search box to be sure which types of documents you are searching. The Serials Set is a miscellany of documents, but otherwise, Congressional documents are kept distinct from legislative documents and Member information and so on.