Perhaps you should try some spelling variations:
mittelbar » mittelbare, ermittelbar, unmittelbare
unmittelbar » unmittelbare, unermittelbar, ununmittelbare
unmittelbaren » unmittelbareen, unermittelbaren, ununmittelbareen, unmittelbare
unmittelbareen » unmittelbareeen, unermittelbareen, ununmittelbareeen, unmittelbarsten, unmittelbare, unmittelbarer
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 (unmittelbar OR (unmittelbaren OR unmittelbareen))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((mittelbar or mittelbach) or (unmittelbar or (unmittelbaren OR unmittelbareen)))".
• Adding a wildcard symbol may retrieve word variants: ((mittelbar or mittelbach) or (unmittelbar or (unmittelbaren OR unmittelbareen)))*.