Perhaps you should try some spelling variations:
heilkunde 1991 » heilkunde 15.15, heilkunde 1, heilkunde 10
heilkunde 11 » heilkunde 1, heilkunde 10, heilkunde 18
heilkunde 16 » heilkunde 6, heilkunde 1, heilkunde 10
verh.born.dt.ges.hno- » very.born.dt.ges.hno-, ver.born.dt.ges.hno-, vers.born.dt.ges.hno-, verh.born.dt.gets.hno-, verh.born.dt.gels.hno-, verh.born.dt.gems.hno-

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.born.dt.ges.hno-((heilkunde 1991) OR (((heilkunde 11) OR (heilkunde 16)))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "verh.born.dt.ges.hno-((heilkunde 1991) or (((heilkunde 11) OR (heilkunde 16))))".
• Adding a wildcard symbol may retrieve word variants: verh.born.dt.ges.hno-((heilkunde 1991) or (((heilkunde 11) OR (heilkunde 16))))*.