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