Perhaps you should try some spelling variations:
mittelbar » unmittelbar, ermittelbar, unmittelbare
mittelbare » unmittelbare, ermittelbare, unmittelbaree
ermittelbare » erunmittelbare, erermittelbare, erunmittelbaree, ermittelbar, unmittelbare, vermittelbar
unmittelbaren » ununmittelbaren, unermittelbaren, ununmittelbareen, unmittelbare, unmittelbar
unmittelbaree » ununmittelbaree, unermittelbaree, ununmittelbareee, unmittelbare, unmittelbarer, unmittelbarem

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 (((mittelbare OR ermittelbare) OR unmittelbaren) OR unmittelbaree))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((mittelbar or mittelbach) or (((mittelbare OR ermittelbare) or unmittelbaren) or unmittelbaree))*".