Perhaps you should try some spelling variations:
mittelbar » mittelbare, unmittelbar, ermittelbar
unermittelbar » unermittelbare, unerunmittelbar, unerermittelbar, unvermittelbar, unvermittelbare, unmittelbar
unmittelbaren » unmittelbareen, ununmittelbaren, unermittelbaren, unmittelbare, unmittelbar
mittelbach » mittelbare

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 (unermittelbar OR unmittelbaren)).
• Adding a wildcard symbol may retrieve word variants: ((mittelbar or mittelbach) or (unermittelbar or unmittelbaren))*.