Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
die filosofia » di filosofia, e filosofia, da filosofia
de filosofia » e filosofia, di filosofia, la filosofia
y literatura » la literatura
testo » test, tests, texto

You may be able to get more results by adjusting your search query.

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