Perhaps you should try some spelling variations:
"particle and nonlinear physical" » "particle and nonlinear physics", "particle and nonlinear chemical", "particle and nonlinear optical"
"article and nuclear physical" » "article and nuclear physics", "article and nuclear medical", "article and nuclear optical"

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: (("particle and nonlinear physical") OR ("article and nuclear physical")).
• Removing quotes may allow a broader search: (( particle and nonlinear physical ) or ( article and nuclear physical )).
• Adding a wildcard symbol may retrieve word variants: (("particle and nonlinear physical") or ("article and nuclear physical"))*.