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

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: (("article and nuclear medical") OR ((("article and nonlinear physical") OR ("article and nonlinear optical")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"article and nuclear medical\") or (((\"article and nonlinear physical\") OR (\"article and nonlinear optical\"))))".
• Removing quotes may allow a broader search: (( article and nuclear medical ) or ((( article and nonlinear physical ) OR ( article and nonlinear optical )))).
• Adding a wildcard symbol may retrieve word variants: (("article and nuclear medical") or ((("article and nonlinear physical") OR ("article and nonlinear optical"))))*.