Perhaps you should try some spelling variations:
delle studien » delphi studien, modell studien, welche studien
duale studien » duale studium, scale studien, duales studium
da literature » a literature, da literatura, la literature
filosofia da » filosofia de, filosofia del, filosofia e
e filosofia » la filosofia

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) OR (duale studien)) e filosofia da literature*".