Perhaps you should try some spelling variations:
passiv » passive, massiv, passiven
passivieren » passiveieren, massivieren, passivenieren, passivierende, passivierung, passagieren
passiverer » passiveerer, massiverer, passivenerer, passiverwerb, passiver, passagerer
passieren » passiert, passiven

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: ((passiv OR passivieren) OR (passiverer OR passieren))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((passiv or passivieren) or (passiverer OR passieren))*".