You can check the Session Laws and index for laws passed by topic and corresponding bill numbers. For older Session Law Indexes, see the Cumulative Index page.
In addition to bills that passed, you can find information about all bills introduced from 1995 to the present on the Legislature's Bills web page, which includes a topic search.
To identify bills older than 1995, use the House Journals and Senate Journals in print, which are available in many libraries, including the Legislative Reference Library. The House Journal or Senate Journals index for a particular session often has a topical index of Senate and House bills introduced in that session. See the Legislative History Guide for more information about researching bills older than 1995.
The Senate Information Office (651-296-0504), the House Index office (651-296-6646), and the Legislative Reference Library (651-296-8338) can help you find bills from previous sessions.