Perhaps you should try some spelling variations:
"particle concentrations" » "particle concentration", "particle penetration", "trace concentrations"
"particle accelerations" » "particle acceleration", "particles acceleration", "particelle acceleratori"
"particle correlations" » "partial correlations", "partial correlation", "particle creation"
"particle accelerator" » "particle acceleration"
"particle accelerators" » "particle accelerations", "particle accelerated", "particle acceleration", "particle accelerating"
"particle accelerate" » "particles accelerated", "particle acceleraton", "particle acceleration"

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 accelerator") OR ((((((("particle accelerators") OR ("particle accelerations"))) OR ("particle accelerate"))) OR ((("particle accelerations") OR ((("particle concentrations") OR ("particle correlations")))))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"particle accelerator\") or (((((((\"particle accelerators\") or (\"particle accelerations\"))) or (\"particle accelerate\"))) or (((\"particle accelerations\") or (((\"particle concentrations\") OR (\"particle correlations\"))))))))".
• Removing quotes may allow a broader search: (( particle accelerator ) or ((((((( particle accelerators ) or ( particle accelerations ))) or ( particle accelerate ))) or ((( particle accelerations ) or ((( particle concentrations ) OR ( particle correlations )))))))).
• Adding a wildcard symbol may retrieve word variants: (("particle accelerator") or ((((((("particle accelerators") or ("particle accelerations"))) or ("particle accelerate"))) or ((("particle accelerations") or ((("particle concentrations") OR ("particle correlations"))))))))*.