Perhaps you should try some spelling variations:
mittelbar » mittelbare, unmittelbar, ermittelbar
ermittelbare » ermittelbaree, erunmittelbare, erermittelbare, ermittelbar, mittelbare, vermittelbar
unmittelbare » unmittelbaree, ununmittelbare, unermittelbare, unmittelbar, ermittelbar

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 (ermittelbare OR unmittelbare)).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(mittelbar or (ermittelbare OR unmittelbare))".
• Adding a wildcard symbol may retrieve word variants: (mittelbar or (ermittelbare OR unmittelbare))*.