Perhaps you should try some spelling variations:
"improving firms performance metrics." » "improving firms performance measures.", "improving firm performance metrics.", "improving firm performances metrics.", "improving funds performance metrics.", "improving farmers performance metrics.", "importing firms performance metrics.", "improving air performance metrics."
"improving lead performance _." » "improving end performance _.", "improving esd performance _.", "improving reward performance _.", "improving legal performance _.", "improving land performance _.", "improving eap performance _."

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