Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
die filosofia » di filosofia, e filosofia, da filosofia
de literatura » de litterature, la literatura, y literatura
de filosofia » e filosofia, di filosofia, la filosofia
test duale » test double, test delle, test orale

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