Perhaps you should try some spelling variations:
passiven » passive, passion
massiv » massive
massiveeren » massiveeeren, massivere, massivdecken, massivteilen
passiveren » passieren, passiverer, passiver
passivieren » passivierende, passivierung, passieren
massigeren » massiger, massigen, massivere

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 massiv) OR ((passiveren OR passivieren) OR (massigeren OR massiveeren))).
• Adding a wildcard symbol may retrieve word variants: ((passiven or massiv) or ((passiveren or passivieren) or (massigeren or massiveeren)))*.