Perhaps you should try some spelling variations:
"research professor" » "research profession", "research process", "search processor"
"research processes" » "research process", "research procedures", "research projects"
"research prozess" » "research process", "research progress", "research propels"

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