Perhaps you should try some spelling variations:
"improving firms performance contract." » "improving firms performance contracts.", "improving firm performance contract.", "improving firm performances contract.", "improving funds performance contract.", "improving farmers performance contract.", "improving air performance contract.", "improving birth performance contract."
"improving loan performance review." » "improving loan performance risk.", "improving loan performance evidence.", "improving poor performance review.", "improving bank performance review.", "improving _ performance review.", "improving local performance review.", "improving land performance review.", "improving road performance review."

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