Perhaps you should try some spelling variations:
"particle acceleration" » "particle accelerators"
"partially accelerated" » "partially correlated", "partially integrated", "partially averaged"
"particle accelerator" » "particle accelerators"
"naturally accelerate" » "naturally regenerated"
"particle accelerate" » "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 accelerate") OR ((("partially accelerated") OR ("naturally accelerate")))))).
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"particle accelerator\") or (\"particle acceleration\"))) or (((\"particle accelerate\") or (((\"partially accelerated\") OR (\"naturally accelerate\"))))))".
• Removing quotes may allow a broader search: (((( particle accelerator ) or ( particle acceleration ))) or ((( particle accelerate ) or ((( partially accelerated ) OR ( naturally accelerate )))))).
• Adding a wildcard symbol may retrieve word variants: (((("particle accelerator") or ("particle acceleration"))) or ((("particle accelerate") or ((("partially accelerated") OR ("naturally accelerate"))))))*.