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

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 OR ermittelbar) OR unmittelbare)).
• Adding a wildcard symbol may retrieve word variants: ((mittelbar or ermittelbare) or ((unmittelbare or ermittelbar) or unmittelbare))*.