Perhaps you should try some spelling variations:
e literatura » de literatura, y literatura, e literatur
rosi modell » osi model, osi modells, rssi model
filosofia e » filosofia de, filosofia del
osi modell » osi model
studien 3 » 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) OR (osi modell)) ((studien 3) OR (studien _)) filosofia e literatura.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((rosi modell) OR (osi modell)) ((studien 3) or (studien _)) filosofia e literatura".
• Adding a wildcard symbol may retrieve word variants: ((rosi modell) OR (osi modell)) ((studien 3) or (studien _)) filosofia e literatura*.