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."

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."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"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."))*.