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