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))".
• Adding a wildcard symbol may retrieve word variants: ((((research professor) OR (research prozess))) or (research processes))*.