Perhaps you should try some spelling variations:
filosofia la » filosofia da, filosofica da, filosofia das
filosofia le » filosofia de, filosofia e, filosofia del
rosi modell » osi model, osi modells, rssi model
osi modell » osi model
studien e » studien es, studien _, studien 3

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