Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
filosofia la » filosofia da, filosofica da, filosofia das
filosofia le » filosofia de, filosofia e, filosofia del
tests duale » tests due, tests scale, tests damage
studien die » studie die, studien der

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: tests duale studien die ((filosofia la) OR (filosofia le)) literatura.
• Adding a wildcard symbol may retrieve word variants: tests duale studien die ((filosofia la) or (filosofia le)) literatura*.