Perhaps you should try some spelling variations:
"improving maternal performance review." » "improving materials performance review.", "improving external performance review.", "improving national performance review.", "improve maternal performance review.", "improving water performance review.", "improving maternal performance risk.", "improving maternal performance evidence."
"improving rural performance metrics." » "improving rural performance measures.", "improving euract performance metrics.", "improving larval performance metrics.", "improving pupil performance metrics."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving rural performance metrics.") OR ("improving maternal performance review."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving rural performance metrics.\") OR (\"improving maternal performance review.\"))*".
• Removing quotes may allow a broader search: (( improving rural performance metrics. ) OR ( improving maternal performance review. ))*.