Perhaps you should try some spelling variations:
"improving air performance review." » "improving air performance risk.", "improving air performance evidence.", "improving zur performance review.", "improving bar performance review.", "improving der performance review.", "improving _ performance review."
"improving sewer performance measures." » "improving power performance measures.", "improving sector performance measures.", "improving better performance measures.", "improving sewerage performance measures.", "improving sales performance measures."

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 air performance review.") or ("improving sewer performance measures."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving air performance review.") OR ("improving sewer performance measures.")).
• Removing quotes may allow a broader search: (( improving air performance review. ) or ( improving sewer performance measures. )).
• Adding a wildcard symbol may retrieve word variants: (("improving air performance review.") or ("improving sewer performance measures."))*.