Perhaps you should try some spelling variations:
mittelbare » unmittelbare, unmittelbaren, unmittelbaree
mittelbar » unmittelbar, unmittelbare
ermittelbar » erunmittelbar, erunmittelbare, unmittelbar
mittelbisau » mittelbau, mittelbis

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: (((mittelbare OR mittelbar) OR ermittelbar) OR mittelbisau).
• Adding a wildcard symbol may retrieve word variants: (((mittelbare or mittelbar) or ermittelbar) or mittelbisau)*.