Perhaps you should try some spelling variations:
ihrer grenzgebiete » ihre grenzgebiete, ihren grenzgebieten, der grenzgebiete
modern purveyors » modern purgatory, power purveyor
modern surveys » oder surveys, modern surgery, models survey
modern survey » modern surgery, models survey, model survey
other surveys » other survey, other surgeons
user surveys » use surveys, user survey, cluster surveys
2c a » 12c a, 2 a, c a

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: %ergebnisse der mathematik und ((ihrer grenzgebiete) OR (im grenzgebiet)). 2. folge%2c a series of ((((modern surveys) OR (((modern purveyors) OR (modern survey))))) OR (((user surveys) OR (other surveys)))) in mathematics%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%ergebnisse der mathematik und ((ihrer grenzgebiete) or (im grenzgebiet)). 2. folge%2c a series of ((((modern surveys) or (((modern purveyors) OR (modern survey))))) or (((user surveys) or (other surveys)))) in mathematics%22".
• Adding a wildcard symbol may retrieve word variants: %ergebnisse der mathematik und ((ihrer grenzgebiete) or (im grenzgebiet)). 2. folge%2c a series of ((((modern surveys) or (((modern purveyors) OR (modern survey))))) or (((user surveys) or (other surveys)))) in mathematics%22*.