Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
die filosofia » de filosofia, e filosofia, da filosofia
da literatura » la literatura, a literatura, de literatura
di filosofia » la filosofia, e filosofia

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 test) duale studien ((die filosofia) OR (di filosofia)) da literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "(testo or test) duale studien ((die filosofia) OR (di filosofia)) da literatura".
• Adding a wildcard symbol may retrieve word variants: (testo or test) duale studien ((die filosofia) OR (di filosofia)) da literatura*.