Perhaps you should try some spelling variations:
"particle acceleration" » "particle accelerators"
"partially accelerated" » "partially integrated", "partially averaged", "partially degenerate"
"particle accelerator" » "particle accelerators"
"naturally accelerate" » "naturally regenerated"
"partially correlated" » "spatially correlated", "serially correlated", "partially connected"

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