Perhaps you should try some spelling variations:
passiver » passiert
passiverwerb » passiertwerb, passiverer
passively » massively, passivity
passiven » passion
passivenener » passionener, passivierender, passiverer

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