Perhaps you should try some spelling variations:
da literatura » la literatura, a literatura, de literatura
filosofia da » filosofia de, filosofia del, filosofia e
test delphi » fast delphi, belts delphi
studien der » studien die, studenten der
studie der » studium 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 ((studien der) OR (studie der)) filosofia da literatura.
• Adding a wildcard symbol may retrieve word variants: test delphi ((studien der) or (studie der)) filosofia da literatura*.