Using Penn's Articles Plus database is a good place to start your search. You will likely yield many results from a search, so consider using the filters on the side to help you narrow your topic. Sometimes you will have direct access to that article (through Penn Libraries), but sometimes you need to request that article through Interlibrary Loan.
The following list provides the top subject-specific research databases for locating political science and public policy journals and articles. At the bottom, there are also China-specific databases that might help with your research as well.