Perhaps you should try some spelling variations:
"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."
"improving can performance evidence." » "improving bank performance evidence.", "improving loan performance evidence.", "improving care performance evidence.", "improving land performance evidence.", "improving tax performance evidence.", "improving co performance evidence."

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 can performance evidence."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving air performance risk.\") OR (\"improving can performance evidence.\"))*".
• Removing quotes may allow a broader search: (( improving air performance risk. ) OR ( improving can performance evidence. ))*.