Perhaps you should try some spelling variations:
duale studies » duale studien, scale studies, duale studium
filosofia da » filosofia del, filosofia e, filosofia della
filosofia de » filosofia del
test duale » test double, test delle, test orale
studies da » studies dna, studies das, studies dan

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 studies da ((filosofia da) OR (filosofia de)) literature*.