When you are searching for academic articles or scholarly articles, it's important to use the terms that researchers within your discipline use-- in some cases, you will get very different results if you use "representative democracy" versus if you use "representative government"
It's important to think of other ways of saying the same thing-- multiple combinations of terms or short phrases can get you closer to what you may want or need for your research. Using "AND" / "OR" between your search terms can broaden ("OR") or narrow ("AND") your search.
Make an appointment with a librarian to help you refine your search (and learn a few insider tips along the way!)