Perhaps you should try some spelling variations:
"particle accelerations" » "particle acceleration", "particles acceleration", "particle concentrations"
"particle penetration" » "particle generation", "particle concentration", "particle separation"
"particle accelerators" » "particle accelerations", "particle accelerated", "particle accelerate", "particle acceleration"
"particle accelerator" » "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 accelerators") OR ((("particle accelerations") OR ("particle penetration"))))) OR ("particle accelerator")).
• Removing quotes may allow a broader search: (((( particle accelerators ) or ((( particle accelerations ) or ( particle penetration ))))) or ( particle accelerator )).
• Adding a wildcard symbol may retrieve word variants: (((("particle accelerators") or ((("particle accelerations") or ("particle penetration"))))) or ("particle accelerator"))*.