Perhaps you should try some spelling variations:
duale studien » duale studium, scale studien, duales studium
la literatura » la litterature, a literature
de filosofia » e filosofia, di filosofia, la filosofia
studien de » studien der, studien die, studien des
testo » test, tests, texto

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 duale studien de filosofia ((y literatura) OR (la literatura)).
• Adding a wildcard symbol may retrieve word variants: testo duale studien de filosofia ((y literatura) or (la literatura))*.