Perhaps you should try some spelling variations:
"improving frs performance contract." » "improving frs performance contracts.", "improving firms performance contract.", "improving mfis performance contract.", "improving als performance contract.", "improving ers performance contract.", "improving fast performance contract."
"improving past performance series." » "improving past performance studies.", "improving past performance size.", "improving plant performance series.", "improving port performance series.", "improving transit performance series.", "improving fast performance series.", "improving post performance series."

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: (("improving past performance series.") OR ("improving frs performance contract."))~.
• Removing quotes may allow a broader search: (( improving past performance series. ) or ( improving frs performance contract. ))~.
• Adding a wildcard symbol may retrieve word variants: (("improving past performance series.") or ("improving frs performance contract."))*.