Perhaps you should try some spelling variations:
mittelbau » mittelbare, mittelbach
mittelbar » mittelbare, ermittelbar, unmittelbare
unmittelbaren » unmittelbareen, unermittelbaren, ununmittelbareen, unmittelbare
unmittelbar » unmittelbare, unermittelbar, ununmittelbare
unermittelbar » unermittelbare, unerermittelbar, unerunmittelbare, unvermittelbar, unvermittelbare, ermittelbar

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