Perhaps you should try some spelling variations:
research professor » research profession, research progresson, research process
research problems » research process, research project, research program
research progress » research program, research project, research projects

You may be able to get more results by adjusting your search query.

• If you are trying to use Boolean operators, they must be ALL CAPS: ((research professor) OR (((research problems) OR (research progress)))).
• Adding a wildcard symbol may retrieve word variants: ((research professor) or (((research problems) or (research progress))))*.