Perhaps you should try some spelling variations:
ihrer grenzgebiete » ihren grenzgebieten, der grenzgebiete, deren grenzgebiete
mathematical union » mathematical function, mathematical question, mathematical solution
ihre grenzgebiete » ihren grenzgebieten, die grenzgebiete, im grenzgebiet
mathematical und » mathematica und, mathematical using, mathematical user
modern surveys » modern purveyors, modern surgery, models survey
modern survey » modern surgery, models survey, model survey
oder surveys » der surveys, other surveys, cover surveys

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 ((mathematical und) OR (mathematical union)) ((ihrer grenzgebiete) OR (ihre grenzgebiete)). 2. folge, a series of ((((modern surveys) OR (oder surveys))) OR (modern survey)) in mathematics.
• The words AND, OR and NOT may confuse the search; try adding quotes: "ergebnisse der ((mathematical und) or (mathematical union)) ((ihrer grenzgebiete) or (ihre grenzgebiete)). 2. folge, a series of ((((modern surveys) OR (oder surveys))) or (modern survey)) in mathematics".
• Adding a wildcard symbol may retrieve word variants: ergebnisse der ((mathematical und) or (mathematical union)) ((ihrer grenzgebiete) or (ihre grenzgebiete)). 2. folge, a series of ((((modern surveys) OR (oder surveys))) or (modern survey)) in mathematics*.