Perhaps you should try some spelling variations:
"particles acceleration" » "particle acceleration", "parallel acceleration", "particles preparation"
"principles application" » "principles applications"
"particles application" » "particular application", "partial application"
"particle accelerator" » "particle acceleration"
"particle accelerators" » "particle accelerations", "particle accelerated", "particle accelerate", "particle accelerating"

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