Perhaps you should try some spelling variations:
"improving country performance review." » "improving country performance risk.", "improving country performance evidence.", "improving voluntary performance review.", "importing country performance review.", "borrowing country performance review."
"improving poor performance series." » "improving poor performance metrics.", "improving poor performance reviews.", "improving poor performance targets.", "improving export performance series.", "improving sector performance series.", "improving _ performance series.", "improving power performance series.", "improving food performance series.", "improving indoor 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 country performance review.") or ("improving poor performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving country performance review.") OR ("improving poor performance series.")).
• Removing quotes may allow a broader search: (( improving country performance review. ) or ( improving poor performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving country performance review.") or ("improving poor performance series."))*.