Perhaps you should try some spelling variations:
ihren grenzgebieten » ihre grenzgebiete
22ergebnisse der » ergebnisse der, endergebnisse der, undergebnisse der
modern surveys » oder surveys, modern purveyors, models survey
modern surgery » open surgery, modern slavery
modern survey » models survey, model survey, modeling survey
12c a » 12c _
2c a » 2 a, c a, 20 a

Try widening your search to All Fields.

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: %22ergebnisse der (mathematik OR mathematical) und ((im grenzgebiet) OR (ihren grenzgebieten)). 2. folge%((2c a) OR (12c a)) series of ((((modern surveys) OR (modern surgery))) OR (modern survey)) in mathematics%22.
• The words AND, OR and NOT may confuse the search; try adding quotes: "%22ergebnisse der (mathematik or mathematical) und ((im grenzgebiet) or (ihren grenzgebieten)). 2. folge%((2c a) OR (12c a)) series of ((((modern surveys) or (modern surgery))) or (modern survey)) in mathematics%22".
• Adding a wildcard symbol may retrieve word variants: %22ergebnisse der (mathematik or mathematical) und ((im grenzgebiet) or (ihren grenzgebieten)). 2. folge%((2c a) OR (12c a)) series of ((((modern surveys) or (modern surgery))) or (modern survey)) in mathematics%22*.