At the end of a jury trial, members of the jury are instructed by the judge on what law is applicable to the case at hand. Practitioners may request that certain instructions be provided to the jury, so it is important to understand how and where to find them. Additionally, jury instructions can be a tremendously helpful resource for legal research, as they state in a clear and concise manner what elements need to be proven, pertinent cases and statutes, burdens of proof, etc.
The National Center for State Courts' site is another helpful resource.
Westlaw: jury instructions are included under main Secondary Sources link or in the secondary source materials for a given state
Lexis Advance: from the main page, click on Jury Instructions from the Content Type tab. Alternatively, you can run a search from the main search bar and set a filter for the category Jury Instructions, along with other relevant filters.