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

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