Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiven » passive, passion
massiveren » massivere, massigeren, massivement
passivieren » passivierende, passivierung, 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: (passiver OR (passiven OR (massiveren OR passivieren))).
• Adding a wildcard symbol may retrieve word variants: (passiver or (passiven or (massiveren or passivieren)))*.