Perhaps you should try some spelling variations:
e literatura » de literatura, y literatura, e literatur
rosi modell » osi modell, osi model, osi modells
filosofia e » filosofia de, filosofia del
studien 3 » studien 5
studien 4 » studien 5

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: rosi modell ((((studien 3) OR (studien 4))) OR (studien _)) filosofia e literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "rosi modell ((((studien 3) OR (studien 4))) or (studien _)) filosofia e literatura".
• Adding a wildcard symbol may retrieve word variants: rosi modell ((((studien 3) OR (studien 4))) or (studien _)) filosofia e literatura*.