Perhaps you should try some spelling variations:
passiver » passively, passiert
passiverer » passivelyer, passierter, passiverwerb, passivieren, passieren
passiven » passion
passivene » passione, passiveand, passively, passives
aktivierende » aktivierenden, aktivieren, motivierende

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