Perhaps you should try some spelling variations:
delle studien » duale studien, delphi studien, modell studien
die filosofia » di filosofia, de filosofia, da filosofia
de literatura » de litterature, la literatura, y literatura
e filosofia » la filosofia
tesi delle » testi delle, test delle, testi della

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: "tesi delle studien ((die filosofia) OR (e filosofia)) de literatura".
• Adding a wildcard symbol may retrieve word variants: tesi delle studien ((die filosofia) OR (e filosofia)) de literatura*.