Perhaps you should try some spelling variations:
passiven » passive, passion
passivenely » passiveely, passionely, passively
passivieren » passivierende, passivierung, passieren
massivierung » passivierung, passivierungs, massierung
passiverer » passiverwerb, passiver, passieren

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: ((passiven OR (passivieren OR massivierung)) OR (passivenely OR passiverer)).
• Adding a wildcard symbol may retrieve word variants: ((passiven or (passivieren or massivierung)) or (passivenely or passiverer))*.