Perhaps you should try some spelling variations:
le literatura » la literatura, de literatura, e literatura
frage studien » lage studien, frage stellen, erste studien
ds filosofia » di filosofia, de filosofia, la filosofia
da filosofia » la filosofia, di filosofia, a filosofia
test frage » test frame, test page, test image

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 frage studien ((ds filosofia) OR (da filosofia)) le literatura.
• Adding a wildcard symbol may retrieve word variants: test frage studien ((ds filosofia) or (da filosofia)) le literatura*.