Perhaps you should try some spelling variations:
"research professional" » "researching professional", "resources professional", "health professional"
"research professor" » "research profession", "search processor", "research progression"
"research processes" » "research procedures", "research projects", "research progress", "research progresses", "research projectses", "research problemses"
"research prozess" » "research progress", "research propels", "research proteases"
"research process" » "research progress", "research projects", "research problems"

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