Perhaps you should try some spelling variations:
delphi studien » delphi studie, delphi study
delle studien » duale studien, modell studien, welche studien
le literatura » la literatura, de literatura, e literatura
filosofia le » filosofia de, filosofia e, filosofia del
e filosofia » la 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: test ((delle studien) OR (delphi studien)) e filosofia le literatura.
• Adding a wildcard symbol may retrieve word variants: test ((delle studien) or (delphi studien)) e filosofia le literatura*.