Although CRS began in 1914, for most of CRS' history Congress added controversial language to each year's appropriations bill prohibiting CRS from distributing its reports to the public without Congressional approval. After years of opposition to this policy, in 2018, Congress passed an appropriations bill that not only allowed but affirmatively required CRS to make its reports publicly available.
CRS is slowly releasing its reports on its website:
Additionally, other websites and databases provide access to large collections of reports that have previously made their way out of Congress.
The most comprehensive and usable source is currently the subscription ProQuest Congressional database:
If you are not a current UCLA student, faculty, or staff member, and cannot come to the UCLA campus to access ProQuest Congressional from the UCLA wireless or computers, you can also access thousands of CRS reports on various free websites: