Perhaps you should try some spelling variations:
passiv » passive, massiv, passiven
passiveerer » passiveeerer, massiveerer, passiveneerer, passiverer, passivieren, passiverwerb
massivere » massiver, massive, massively
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: ((passiv OR (massivere OR passiveerer)) OR aktivierende).
• Adding a wildcard symbol may retrieve word variants: ((passiv or (massivere or passiveerer)) or aktivierende)*.