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

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 projects ) OR ( ((research problems) OR (((research progress) OR (research project)))) )))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( research professor ) or ((( research projects ) or ( ((research problems) or (((research progress) OR (research project)))) ))))".
• Adding a wildcard symbol may retrieve word variants: (( research professor ) or ((( research projects ) or ( ((research problems) or (((research progress) OR (research project)))) ))))*.