Perhaps you should try some spelling variations:
"improving human performance measures." » "improving loan performance measures.", "improving thermal performance measures.", "improving chain performance measures."
"improving firms performance risks." » "improving firm performance risks.", "improving firm performances risks.", "improving funds performance risks.", "improving firms performance risk.", "improving farmers performance risks.", "importing firms performance risks.", "improving air performance risks."

You may be able to get more results by adjusting your search query.

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving human performance measures.") OR ("improving firms performance risks."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving human performance measures.\") OR (\"improving firms performance risks.\"))*".
• Removing quotes may allow a broader search: (( improving human performance measures. ) OR ( improving firms performance risks. ))*.