Perhaps you should try some spelling variations:
der mathematical » her mathematical, mer mathematical, order mathematical
other surveys » other survey, other surgeons
oder surveys » der surveys, cover surveys, our surveys
user surveys » use surveys, user survey, cluster surveys
und ihrer » und ihr

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