Perhaps you should try some spelling variations:
"Improving human performance contract." » "Improving human performance contracts.", "Improving loan performance contract.", "Improving thermal performance contract.", "Improving chain performance contract."
"Improving human performance metrics." » "Improving human performance measures.", "Improving loan performance metrics.", "Improving thermal performance metrics.", "Improving chain performance metrics."

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 metrics.") OR ("Improving human performance contract."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"Improving human performance metrics.\") OR (\"Improving human performance contract.\"))*".
• Removing quotes may allow a broader search: (( Improving human performance metrics. ) OR ( Improving human performance contract. ))*.