Perhaps you should try some spelling variations:
verh.bern.dt.gel.hno-heilkunde » ver.bern.dt.gel.hno-heilkunde, vers.bern.dt.gel.hno-heilkunde, verm.bern.dt.gel.hno-heilkunde, verh.been.dt.gel.hno-heilkunde, verh.ben.dt.gel.hno-heilkunde
vera.bern.dt.gel.hno-heilkunde » vera.been.dt.gel.hno-heilkunde, vera.ben.dt.gel.hno-heilkunde, ver.bern.dt.gel.hno-heilkunde, vers.bern.dt.gel.hno-heilkunde
verb.born.dt.gels.hno-heilkunde » ver.born.dt.gels.hno-heilkunde, vers.born.dt.gels.hno-heilkunde, verb.born.dt.gets.hno-heilkunde, verb.born.dt.geld.hno-heilkunde
very.born.dt.gels.hno-heilkunde » very.born.dt.gets.hno-heilkunde, very.born.dt.geld.hno-heilkunde

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: (( (verh.bern.dt.gel.hno-heilkunde OR vera.bern.dt.gel.hno-heilkunde) 1991 ) OR (( verb.born.dt.gels.hno-heilkunde OR very.born.dt.gels.hno-heilkunde) 1991 )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( (verh.bern.dt.gel.hno-heilkunde OR vera.bern.dt.gel.hno-heilkunde) 1991 ) or (( verb.born.dt.gels.hno-heilkunde or very.born.dt.gels.hno-heilkunde) 1991 ))".
• Adding a wildcard symbol may retrieve word variants: (( (verh.bern.dt.gel.hno-heilkunde OR vera.bern.dt.gel.hno-heilkunde) 1991 ) or (( verb.born.dt.gels.hno-heilkunde or very.born.dt.gels.hno-heilkunde) 1991 ))*.