Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiveren » passiveen, passivelyen, passierten, passieren, passiverer, passageren
passiven » passive
passivieren » passivierende, passivierung, passieren
passivee » passive, passives, passivem

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 (passiveren OR passiven))) OR (passivieren OR passivee)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((passiver or (passion or (passiveren OR passiven))) or (passivieren or passivee))".
• Adding a wildcard symbol may retrieve word variants: ((passiver or (passion or (passiveren OR passiven))) or (passivieren or passivee))*.