Perhaps you should try some spelling variations:
mittelbar » ermittelbar
unmittelbar » unermittelbar
unmittelbaree » unermittelbaree, unmittelbaren, unmittelbarer, unmittelbarem, ermittelbare, ununmittelbarene
unmittelbare » unermittelbare, ermittelbar, ununmittelbaren
mittelbare » ermittelbare, unmittelbaren
mittelbau » 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 (unmittelbaree OR unmittelbare))) OR (mittelbau OR mittelbare)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((mittelbar or (unmittelbar or (unmittelbaree or unmittelbare))) or (mittelbau OR mittelbare))".
• Adding a wildcard symbol may retrieve word variants: ((mittelbar or (unmittelbar or (unmittelbaree or unmittelbare))) or (mittelbau OR mittelbare))*.