Perhaps you should try some spelling variations:
mittelbau » mittelbare, mittelbach
unmittelbaree » unmittelbare, unmittelbarer, unmittelbarem, unmittelbareee, ununmittelbaree, unermittelbaree
mittelbar » mittelbare, unmittelbar, ermittelbar
unmittelbaren » unmittelbareen, ununmittelbaren, unermittelbaren, unmittelbare, unmittelbar

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: (((mittelbau OR unmittelbaree) OR mittelbar) OR unmittelbaren).
• Adding a wildcard symbol may retrieve word variants: (((mittelbau or unmittelbaree) or mittelbar) or unmittelbaren)*.