Perhaps you should try some spelling variations:
del literatura » de literatura, pela literatura, da literatura
duale studien » duale studium, scale studien, duales studium
de filosofia » di filosofia, la filosofia, a filosofia
tests duale » tests due, tests scale, tests damage
e filosofia » la filosofia

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 duale studien ((de filosofia) OR (e filosofia)) del literatura".
• Adding a wildcard symbol may retrieve word variants: tests duale studien ((de filosofia) OR (e filosofia)) del literatura*.