If you want to search for a specific case or law review articles on a topic, start with Lexis Uni or WestLaw Campus Research. Lexis and WestLaw are the largest publishers of legal documents and research.
The Legal Information Institute (LII) at Cornell University Law School is a "small not-for-profit group that believes everyone should be able to read and understand the laws that govern them, without cost." They fulfill this mission by "publishing law online, for free, and creating materials that help people understand" the law. Collections include:
World -- National and International laws