Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiven » passive
passivieren » passivierung, passieren, passagieren
passivierende » passivierungde, passierende, passagierende, passivierender, aktivierende, passivierung

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