Perhaps you should try some spelling variations:
der filosofia » de filosofia, e filosofia, di filosofia
le literatura » la literatura, de literatura, e literatura
filosofia le » filosofia de, filosofia e, filosofia del
test delphi » belts delphi
studien der » studie der, studenten der

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