Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
ds filosofia » di filosofia, de filosofia, la filosofia
da filosofia » la filosofia, di filosofia, a 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 ((ds filosofia) OR (da filosofia)) a literature.
• Adding a wildcard symbol may retrieve word variants: test duale studien ((ds filosofia) or (da filosofia)) a literature*.