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

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