Perhaps you should try some spelling variations:
"particle and nuclear material" » "particle and nuclear matrix", "particle and nuclear matter"
"particle and nuclear materials" » "particle and nuclear matrixs", "particle and nuclear matters"
"particle and nuclear medical" » "particle 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: (("particle and nuclear medical") OR ((("particle and nuclear material") OR ("particle and nuclear materials")))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"particle and nuclear medical\") or (((\"particle and nuclear material\") OR (\"particle and nuclear materials\"))))".
• Removing quotes may allow a broader search: (( particle and nuclear medical ) or ((( particle and nuclear material ) OR ( particle and nuclear materials )))).
• Adding a wildcard symbol may retrieve word variants: (("particle and nuclear medical") or ((("particle and nuclear material") OR ("particle and nuclear materials"))))*.