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

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 program")))))).
• 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 program\"))))))".
• Removing quotes may allow a broader search: (( research professor ) or ((((( research process ) or ( research projects ))) or ((( research problems ) OR ( research program )))))).
• Adding a wildcard symbol may retrieve word variants: (("research professor") or ((((("research process") or ("research projects"))) or ((("research problems") OR ("research program"))))))*.