Perhaps you should try some spelling variations:
"improving air performance review." » "improving air performance risk.", "improving zur performance review.", "improving bar performance review.", "improving der performance review.", "improving _ performance review."
"improving civic performance evidence." » "improving music performance evidence.", "improving basic performance evidence.", "improving specific performance evidence.", "improving civil performance evidence.", "improving living 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 review.") or ("improving civic performance evidence."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving air performance review.") OR ("improving civic performance evidence.")).
• Removing quotes may allow a broader search: (( improving air performance review. ) or ( improving civic performance evidence. )).
• Adding a wildcard symbol may retrieve word variants: (("improving air performance review.") or ("improving civic performance evidence."))*.