Perhaps you should try some spelling variations:
"dynamischen systems" » "dynamischen systemen", "dynamischer systeme", "dynamische systeme"
"economic systems" » "economic sectors"
"dynamics system" » "dynamical system", "dynamisches system"
"dynamic systems" » "dynamical systems"
"dynamic system" » "dynamical system"

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: (("dynamical systems") OR ((((((((("dynamic systems") OR ("economic systems"))) OR ("dynamischen systems"))) OR ("dynamic system"))) OR ("dynamics system")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"dynamical systems\") or (((((((((\"dynamic systems\") OR (\"economic systems\"))) or (\"dynamischen systems\"))) or (\"dynamic system\"))) or (\"dynamics system\"))))".
• Removing quotes may allow a broader search: (( dynamical systems ) or ((((((((( dynamic systems ) OR ( economic systems ))) or ( dynamischen systems ))) or ( dynamic system ))) or ( dynamics system )))).
• Adding a wildcard symbol may retrieve word variants: (("dynamical systems") or ((((((((("dynamic systems") OR ("economic systems"))) or ("dynamischen systems"))) or ("dynamic system"))) or ("dynamics system"))))*.