Perhaps you should try some spelling variations:
"vieweg studium; grundkurs mathematik" » "vieweg studium; bruckenkurs mathematik", "vieweg studium; vorkurs mathematik", "vieweg studium; grundkurs informatik"
"reviewed studies; Grundkurs Mathematik" » "review studies; Grundkurs Mathematik", "related studies; Grundkurs Mathematik", "resolved studies; Grundkurs Mathematik"

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; grundkurs mathematik") OR ((("viewed studium; Grundkurs Mathematik") OR ("reviewed studies; Grundkurs Mathematik"))))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"vieweg studium; grundkurs mathematik\") or (((\"viewed studium; Grundkurs Mathematik\") OR (\"reviewed studies; Grundkurs Mathematik\"))))*".
• Removing quotes may allow a broader search: (( vieweg studium; grundkurs mathematik ) or ((( viewed studium; Grundkurs Mathematik ) OR ( reviewed studies; Grundkurs Mathematik ))))*.