Perhaps you should try some spelling variations:
"particle accelerations" » "particle accelerators", "particles acceleration", "particle concentrations", "particle acceleratorss"
"particle acceleration" » "particle accelerators"
"parallel acceleration" » "parallel generation", "parallel application"
"particle accelerator" » "particle accelerators"
"parallel operation" » "parallel generation", "parallel computation", "parallel repetition"

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