This database provides an unannotated version the U.S. Code. Although it does not have annotations, it does provide links to automated extracts of interpreting cases through Bloomberg's Smart Code service.
Maintained by the International Trade Commission (ITC), the electronic version of the current Harmonized Tariff Schedule (HTS) allows a user to browse by Chapter. The web site also provides access to archived versions of the Harmonized Tariff Schedule are available online back to 1987.
Lexis includes full-text of all bills from 1989 to the present. This link leads to the current session, but you can access other sessions by searching for "Congressional Full-text Bills" in the Lexis Search box and selecting the appropriate session from the drop-down menu.