Perhaps you should try some spelling variations:
mittelbar » mittelbare, unmittelbar, ermittelbar
unmittelbare » unmittelbaree, ununmittelbare, unermittelbare, unmittelbar, ermittelbar
unmittelbarn » unmittelbaren, ununmittelbarn, unermittelbarn, unmittelbar, unmittelbarer
mittelbach » mittelbare

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