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

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