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

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