Perhaps you should try some spelling variations:
"improving maternal performance metrics." » "improving materials performance metrics.", "improving external performance metrics.", "improving managerial performance metrics.", "improving maternal performance measures.", "improve maternal performance metrics.", "improving water performance metrics."
"improving national performance risks." » "improving regional performance risks.", "improving operational performance risks.", "improving educational performance risks.", "improving natural performance risks.", "improve national performance risks.", "improving national 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 maternal performance metrics.") or ("improving national performance risks."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving maternal performance metrics.") OR ("improving national performance risks.")).
• Removing quotes may allow a broader search: (( improving maternal performance metrics. ) or ( improving national performance risks. )).
• Adding a wildcard symbol may retrieve word variants: (("improving maternal performance metrics.") or ("improving national performance risks."))*.