Perhaps you should try some spelling variations:
mittelbar » mittelbare, ermittelbar
unmittelbar » unmittelbare, unermittelbar
unmittelbareee » unmittelbareeee, unermittelbareee, unmittelbaren, unmittelbarer, unmittelbarem, ermittelbaree
unmittelbare » unmittelbaree, unermittelbare, ermittelbar
mittelbau » mittelbare, mittelbach

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