Perhaps you should try some spelling variations:
passiver » passive, passiven, passively
passiveren » passiveen, passivenen, passivelyen, passieren, passiverer, passiven
massiv » massive
passiveneren » passieren, passiverer
massigeren » massiger, massigen, massivere
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 massiv) OR ((passiveren OR passiveneren) OR (massigeren OR passivieren))).
• Adding a wildcard symbol may retrieve word variants: ((passiver or massiv) or ((passiveren or passiveneren) or (massigeren or passivieren)))*.