Perhaps you should try some spelling variations:
"improving urban performance evidence." » "improving bank performance evidence.", "improving loan performance evidence.", "improving can performance evidence."
"improving air performance risk." » "improving air performance size.", "improving air performance based.", "improving air performance _.", "improving firm performance risk.", "improving a performance risk.", "improving ii performance risk.", "improving water performance risk.", "improving land performance risk.", "improving _ performance risk."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving air performance risk.") OR ("improving urban performance evidence."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving air performance risk.\") OR (\"improving urban performance evidence.\"))".
• Removing quotes may allow a broader search: (( improving air performance risk. ) OR ( improving urban performance evidence. )).
• Adding a wildcard symbol may retrieve word variants: (("improving air performance risk.") OR ("improving urban performance evidence."))*.