Perhaps you should try some spelling variations:
de litterature » la litterature, et litterature
duale studien » duale studium, scale studien, duales studium
die filosofia » di filosofia, de filosofia, e filosofia
filosofia de » filosofia del
studien die » studie die, studien der

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