Perhaps you should try some spelling variations:
"improving urban performance series." » "improving urban performance metrics.", "improving urban performance reviews.", "improving urban performance review.", "improving bank performance series.", "improving loan performance series.", "improving can performance series."
"improving poor performance series." » "improving poor performance metrics.", "improving poor performance reviews.", "improving poor performance review.", "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 urban performance series.") or ("improving poor performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving urban performance series.") OR ("improving poor performance series.")).
• Removing quotes may allow a broader search: (( improving urban performance series. ) or ( improving poor performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving urban performance series.") or ("improving poor performance series."))*.