Perhaps you should try some spelling variations:
drug studium » drug studies, drugs studies, beruf studium
filosofia da » filosofia de, filosofia e, filosofia della
tests drug » test drug, testing drug, tests during
studium ad » studium am, studium a, studium d

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: "tests drug studium ad ((filosofia da) OR (filosofia del)) literatura*".