Perhaps you should try some spelling variations:
a literatura » la literatura, a literature, y literatura
filosofia a » filosofia da, filosofia la, filosofia e
studien a » studien am, studien _, studien 4
studien 3 » studien _, studien 4, studien 5
test zu » test zur, tests zu, test zum

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "test zu ((studien a) OR (studien 3)) filosofia a literatura*".