Perhaps you should try some spelling variations:
heilkunde 1991 » heilkunde 11, heilkunde 15.15, heilkunde 1
verh.bern.dt.god.hno-heilkunde » very.bern.dt.god.hno-heilkunde, ver.bern.dt.god.hno-heilkunde, verb.bern.dt.god.hno-heilkunde, verh.born.dt.god.hno-heilkunde, verh.ben.dt.god.hno-heilkunde, verh.bern.dt.good.hno-heilkunde
vers.been.dt.geld.hno-heilkunde » verso.been.dt.geld.hno-heilkunde, very.been.dt.geld.hno-heilkunde, ver.been.dt.geld.hno-heilkunde, vers.been.dt.gold.hno-heilkunde
vers.been.dt.gel.hno-heilkunde » verso.been.dt.gel.hno-heilkunde, very.been.dt.gel.hno-heilkunde, ver.been.dt.gel.hno-heilkunde
verse.been.dt.gel.hno-heilkunde » versoe.been.dt.gel.hno-heilkunde, verye.been.dt.gel.hno-heilkunde, vere.been.dt.gel.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.god.hno-heilkunde 1991 ) OR ( (vers.been.dt.geld.hno-heilkunde OR (vers.been.dt.gel.hno-heilkunde OR verse.been.dt.gel.hno-heilkunde)) 1991 )).
• The words AND, OR and NOT may confuse the search; try adding quotes: "(( verh.bern.dt.god.hno-heilkunde 1991 ) or ( (vers.been.dt.geld.hno-heilkunde or (vers.been.dt.gel.hno-heilkunde OR verse.been.dt.gel.hno-heilkunde)) 1991 ))".
• Adding a wildcard symbol may retrieve word variants: (( verh.bern.dt.god.hno-heilkunde 1991 ) or ( (vers.been.dt.geld.hno-heilkunde or (vers.been.dt.gel.hno-heilkunde OR verse.been.dt.gel.hno-heilkunde)) 1991 ))*.