Perhaps you should try some spelling variations:
"dynamischen systems" » "dynamischen systemen", "dynamischer systeme", "dynamische systeme"
"economic systems" » "economic sectors"
"dynamics system" » "dynamic system", "dynamical system", "dynamisches 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 ((((("dynamischen systems") OR ("dynamics system"))) OR ((("dynamic systems") OR ("economic systems")))))).
• Removing quotes may allow a broader search: (( dynamical systems ) or ((((( dynamischen systems ) or ( dynamics system ))) or ((( dynamic systems ) or ( economic systems )))))).
• Adding a wildcard symbol may retrieve word variants: (("dynamical systems") or ((((("dynamischen systems") or ("dynamics system"))) or ((("dynamic systems") or ("economic systems"))))))*.