Perhaps you should try some spelling variations:
delphi studien » delphi studie, delphi study
duale studien » duale studium, scale studien, duales studium
der filosofia » de filosofia, e filosofia, di filosofia
e literatura » de literatura, y literatura, e literatur
filosofia e » filosofia de, filosofia del

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 ((delphi studien) OR (duale studien)) der filosofia e literatura.
• Adding a wildcard symbol may retrieve word variants: test ((delphi studien) or (duale studien)) der filosofia e literatura*.