Perhaps you should try some spelling variations:
mittelbar » mittelbare, unmittelbar, ermittelbar
unermittelbar » unermittelbare, unerunmittelbar, unerermittelbar, unvermittelbar, unvermittelbare, unmittelbar
unmittelbarem » unmittelbareem, ununmittelbarem, unermittelbarem, unmittelbaren, unmittelbarer, unmittelbar, unmittelbarm, ermittelbarm
unmittelbare » unmittelbaree, ununmittelbare, unermittelbare, unmittelbar, ermittelbar
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 (unermittelbar OR (unmittelbarem OR unmittelbare))) OR mittelbisau).
• Adding a wildcard symbol may retrieve word variants: ((mittelbar or (unermittelbar or (unmittelbarem or unmittelbare))) or mittelbisau)*.