Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiveren » passiveen, passivelyen, passierten, passivieren, passieren, passageren
passiverer » passiveer, passivelyer, passierter, passiverwerb, passivieren, passieren
passiven » passive

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: ((passiver OR (passion OR passiveren)) OR (passiven OR passiverer)).
• Adding a wildcard symbol may retrieve word variants: ((passiver or (passion or passiveren)) or (passiven or passiverer))*.