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

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