Perhaps you should try some spelling variations:
passiver » passive, passively, passiert
passiven » passive, passion
passivee » passive, passives, passivem
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 (passivee OR aktivierende)).
• Adding a wildcard symbol may retrieve word variants: ((passiver or passiven) or (passivee or aktivierende))*.