Perhaps you should try some spelling variations:
stufe studien » studie studien, stufen studie, studien studien
de literatura » de litterature, la literatura, y literatura
erste stufe » erster stufe
3 filosofia » a filosofia, y filosofia, _ filosofia
e filosofia » la filosofia

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "erste stufe studien ((3 filosofia) OR (e filosofia)) de literatura".
• Adding a wildcard symbol may retrieve word variants: erste stufe studien ((3 filosofia) OR (e filosofia)) de literatura*.