Perhaps you should try some spelling variations:
passiver » passiven, passively, passiert
massiveren » massivere, massivement, massiven
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 ((passion OR passive) OR ((massiveren OR massigeren) OR passivieren))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(passiver or ((passion or passive) or ((massiveren OR massigeren) or passivieren)))".
• Adding a wildcard symbol may retrieve word variants: (passiver or ((passion or passive) or ((massiveren OR massigeren) or passivieren)))*.