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 based.", "improving basic performance _.", "improving air performance risk.", "improve basic performance risk.", "improving public performance risk."
"improving birth performance risk." » "improving firm performance risk.", "improving high performance risk.", "improving port performance risk.", "improving birth performance size.", "improving birth performance based.", "improving birth performance _.", "improving air performance risk.", "improving health performance risk.", "improving growth performance risk."

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