Perhaps you should try some spelling variations:
mittelbau » mittelbare
mittelbach » mittelbare
mittelbar » mittelbare, unmittelbar, ermittelbar
unermittelbare » unermittelbaree, unerunmittelbare, unerermittelbare, unvermittelbare, unmittelbare, ermittelbare

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