Perhaps you should try some spelling variations:
"research problems" » "research progress", "research project", "research program"
"research prozess" » "research progress", "research propels", "research processes"
"research process" » "research progress", "research projects", "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 prozess") OR ("research process"))) OR ("research problems")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"research prozess\") OR (\"research process\"))) or (\"research problems\"))".
• Removing quotes may allow a broader search: (((( research prozess ) OR ( research process ))) or ( research problems )).
• Adding a wildcard symbol may retrieve word variants: (((("research prozess") OR ("research process"))) or ("research problems"))*.