Perhaps you should try some spelling variations:
"improving urban performance reviews." » "improving urban performance review.", "improving urban performance reports.", "improving urban performance risks.", "improving bank performance reviews.", "improving loan performance reviews.", "improving human performance reviews."
"improving crop performance series." » "improving crop performance studies.", "improving crop performance size.", "improving group performance series.", "improving top performance series.", "improving do performance series.", "improving co performance series.", "improving pro performance series.", "improving macro 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 urban performance reviews.") or ("improving crop performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving urban performance reviews.") OR ("improving crop performance series.")).
• Removing quotes may allow a broader search: (( improving urban performance reviews. ) or ( improving crop performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving urban performance reviews.") or ("improving crop performance series."))*.