Perhaps you should try some spelling variations:
"random dynamical systems" » "quantum dynamical systems"
"quantum chemical system" » "quantum mechanical system", "quantum chemistry system", "quantum chemical systems", "quantum biochemical systems", "quantum 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: (("random dynamical systems") OR ("quantum chemical system")).
• Removing quotes may allow a broader search: (( random dynamical systems ) or ( quantum chemical system )).
• Adding a wildcard symbol may retrieve word variants: (("random dynamical systems") or ("quantum chemical system"))*.