Perhaps you should try some spelling variations:
"improve maternal performance metrics." » "improve national performance metrics.", "improve thermal performance metrics.", "improve lanterns performance metrics.", "improve maternal performance contracts.", "improve maternal performance measures.", "improve maternal performance contract.", "improving maternal performance metrics.", "improve water performance metrics."
"improving school performance targets." » "improving schools performance targets.", "improving preschool performance targets.", "improve school performance targets."

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

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