Perhaps you should try some spelling variations:
"improving basic performance risk." » "improving based performance risk.", "improving bank performance risk.", "improving past performance risk.", "improving basic performance size.", "improving basic performance _.", "improving basic performance data.", "improving air performance risk.", "improve basic performance risk.", "improving public performance risk."
"improving port performance based." » "improving port performance measures.", "improving export performance based.", "improving court performance based.", "improving plant performance based.", "improving poverty performance based.", "improving birth performance based."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving basic performance risk.") or ("improving port performance based."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving basic performance risk.") OR ("improving port performance based.")).
• Removing quotes may allow a broader search: (( improving basic performance risk. ) or ( improving port performance based. )).
• Adding a wildcard symbol may retrieve word variants: (("improving basic performance risk.") or ("improving port performance based."))*.