To get you access to these database search engines, the SU LIbraries pay approximately half a million dollars every year. Take advantage of these resources! Other people don't have access to them and they contain millions of quality scientific articles that are exactly what you need to work on your research projects.
We have close to 200 databases! Depending on the specifics of your project and topic, I can recommend additional places to search and search strategies related to your research question.