Perhaps you should try some spelling variations:
"particle acceleration" » "particle accelerators"
"particle acceleratord" » "particle accelerators", "particle accelerator", "particle acceleraton"
"particle accelerate" » "particles accelerated", "particle accelerator", "particle acceleraton"

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 acceleration") OR ((("particle accelerate") OR ("particle acceleratord")))).
• Removing quotes may allow a broader search: (( particle acceleration ) or ((( particle accelerate ) or ( particle acceleratord )))).
• Adding a wildcard symbol may retrieve word variants: (("particle acceleration") or ((("particle accelerate") or ("particle acceleratord"))))*.