Perhaps you should try some spelling variations:
"nuclear physical" » "nuclear physics", "nonlinear physical"
"nuclear optical" » "nuclear option", "nonlinear optical"
"nuclear medical" » "nuclear medicine", "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: (((("nuclear physical") OR ("nuclear optical"))) OR ("nuclear medical")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"nuclear physical\") OR (\"nuclear optical\"))) or (\"nuclear medical\"))".
• Removing quotes may allow a broader search: (((( nuclear physical ) OR ( nuclear optical ))) or ( nuclear medical )).
• Adding a wildcard symbol may retrieve word variants: (((("nuclear physical") OR ("nuclear optical"))) or ("nuclear medical"))*.