Perhaps you should try some spelling variations:
"related studies; grundkurs mathematik" » "related studies; grundkurs informatik", "related species; grundkurs mathematik"
"viewed studium; bruckenkurs mathematik" » "reviewed studies; bruckenkurs mathematik"

Try widening your search to All Fields.

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: (("vieweg studium; vorkurs mathematik") OR ((("viewed studium; bruckenkurs mathematik") OR ("related studies; grundkurs mathematik")))).
• Removing quotes may allow a broader search: (( vieweg studium; vorkurs mathematik ) or ((( viewed studium; bruckenkurs mathematik ) or ( related studies; grundkurs mathematik )))).
• Adding a wildcard symbol may retrieve word variants: (("vieweg studium; vorkurs mathematik") or ((("viewed studium; bruckenkurs mathematik") or ("related studies; grundkurs mathematik"))))*.