Perhaps you should try some spelling variations:
mittelbar » mittelbare, ermittelbar
unmittelbar » unmittelbare, unermittelbar
unmittelbarem » unmittelbareem, unermittelbarem, unmittelbaren, unmittelbarer, unmittelbarkeit
unmittelbare » unmittelbaree, unermittelbare
mittelbisau » mittelbau, mittelbis

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