Perhaps you should try some spelling variations:
heilkunde 1991 » heilkunde 15.15, heilkunde 1, heilkunde 10
heilkunde 11 » heilkunde 1, heilkunde 10, heilkunde 16
\"verh.bern.dt.gel.hno- » \"ver.bern.dt.gel.hno-, \"vers.bern.dt.gel.hno-, \"verb.bern.dt.gel.hno-, \"verh.been.dt.gel.hno-, \"verh.ben.dt.gel.hno-
\"verh.born.dt.gels.hno-heilkunde » \"ver.born.dt.gels.hno-heilkunde, \"vers.born.dt.gels.hno-heilkunde, \"verb.born.dt.gels.hno-heilkunde, \"verh.born.dt.gets.hno-heilkunde
\"very.born.dt.gels.hno-heilkunde » \"very.born.dt.gets.hno-heilkunde
\"very.born.dt.geld.hno-heilkunde » \"very.born.dt.gold.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 1991) OR (heilkunde 11))\") or ((\"verh.born.dt.gels.hno-heilkunde OR (\"very.born.dt.gels.hno-heilkunde or \"very.born.dt.geld.hno-heilkunde)) 1991\"))".
• The words AND, OR and NOT may confuse the search; try adding quotes: "\"((\\"verh.bern.dt.gel.hno-((heilkunde 1991) OR (heilkunde 11))\\") or ((\\"verh.born.dt.gels.hno-heilkunde or (\\"very.born.dt.gels.hno-heilkunde or \\"very.born.dt.geld.hno-heilkunde)) 1991\\"))\"".
• Removing quotes may allow a broader search: (( verh.bern.dt.gel.hno-((heilkunde 1991) OR (heilkunde 11)) ) or (( verh.born.dt.gels.hno-heilkunde or ( very.born.dt.gels.hno-heilkunde or very.born.dt.geld.hno-heilkunde)) 1991 )).