Perhaps you should try some spelling variations:
"article and nuclear optical" » "article and nuclear option", "article and nonlinear optical"
"articles and nuclear medical" » "articles and nuclear medicine", "articles and nuclear material"

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