Perhaps you should try some spelling variations:
"improving maternal performance review." » "improving national performance review.", "improving thermal performance review.", "improving lanterns performance review.", "improve maternal performance review.", "improving water performance review.", "improving maternal performance risk.", "improving maternal performance evidence."
"improving rural performance series." » "improving rural performance metrics.", "improving rural performance reviews.", "improving rural performance targets.", "improving pupil performance series.", "improving thermal performance series.", "improving overall performance series.", "improving urban performance series.", "improving social performance series."

Try widening your search to All Fields.

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