Perhaps you should try some spelling variations:
"quantum dynamical system" » "quantum dynamics system", "quantum chemical system", "quantum dynamical systems"
"random dynamic systems" » "random dynamical systems", "random economic systems", "random dynamics systems", "freedom dynamic systems"

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: (("quantum dynamical system") OR ("random dynamic systems")).
• Removing quotes may allow a broader search: (( quantum dynamical system ) or ( random dynamic systems )).
• Adding a wildcard symbol may retrieve word variants: (("quantum dynamical system") or ("random dynamic systems"))*.