Perhaps you should try some spelling variations:
passiveen » passiven, passiveand, passiver
passively » massively, passivity, passiven
passiverer » passiverwerb, passiver, passagerer
passieren » passiert, passiven
passivieren » passivierende, passivierung, passagieren

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: (passive OR ((passiveen OR passively) OR ((passiverer OR passieren) OR passivieren))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(passive or ((passiveen OR passively) or ((passiverer or passieren) or passivieren)))".
• Adding a wildcard symbol may retrieve word variants: (passive or ((passiveen OR passively) or ((passiverer or passieren) or passivieren)))*.