Perhaps you should try some spelling variations:
del literature » model literature, abel literature, fuel literature
tests schule » tests scale, testes schedule, tests should
studium 3 » studium _, studium 1, studium im
studium 8 » studium _, studium 1, studium im

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 schule ((studium 3) OR (studium 8)) filosofia del literature".
• Adding a wildcard symbol may retrieve word variants: tests schule ((studium 3) OR (studium 8)) filosofia del literature*.