Perhaps you should try some spelling variations:
teste stadien » erste studien, tertiare stadien, testende studien
de literatura » de litterature, la literatura, y literatura
filosofia de » filosofia del
studien die » studie die
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: teste stadien ((studien die) OR (studien der)) filosofia de literatura.
• Adding a wildcard symbol may retrieve word variants: teste stadien ((studien die) or (studien der)) filosofia de literatura*.