Perhaps you should try some spelling variations:
"article and nonlinear physical" » "article and nonlinear physics", "article and nonlinear chemical", "article and nonlinear optical"
"article and nuclear material" » "article and nuclear materials", "article and nuclear matrix", "article and nuclear matter"

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: (("article and nuclear material") OR ("article and nonlinear physical"))*.
• Removing quotes may allow a broader search: (( article and nuclear material ) or ( article and nonlinear physical ))*.