Perhaps you should try some spelling variations:
"particle nuclear test ban treaty" » "particle number test ban treaty", "particles nuclei test ban treaty", "particle nucleation test ban treaty", "particle nuclear west bank treaty", "particle nuclear test bed treaty"
"particle nuclear test a treaty" » "particle number test a treaty", "particles nuclei test a treaty", "particle nucleation test a treaty", "particle nuclear test _ treaty", "particle nuclear test act treaty"
"particles nuclear test ban treaty" » "particles nuclear west bank treaty", "particles nuclear test bed treaty"

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 nuclear test ban treaty") OR ("particle nuclear test a treaty"))) OR ("particles nuclear test ban treaty")).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"particle nuclear test ban treaty\") OR (\"particle nuclear test a treaty\"))) or (\"particles nuclear test ban treaty\"))".
• Removing quotes may allow a broader search: (((( particle nuclear test ban treaty ) OR ( particle nuclear test a treaty ))) or ( particles nuclear test ban treaty )).
• Adding a wildcard symbol may retrieve word variants: (((("particle nuclear test ban treaty") OR ("particle nuclear test a treaty"))) or ("particles nuclear test ban treaty"))*.