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 port performance series." » "improving port performance studies.", "improving port performance size.", "improving export performance series.", "improving court performance series.", "improving plant performance series.", "improving post performance series.", "improving poor 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 port performance series.") OR ("improving frs performance contract."))~.
• Removing quotes may allow a broader search: (( improving port performance series. ) or ( improving frs performance contract. ))~.
• Adding a wildcard symbol may retrieve word variants: (("improving port performance series.") or ("improving frs performance contract."))*.