Perhaps you should try some spelling variations:
"improving food performance contract." » "improving food performance contracts.", "improving good performance contract.", "improving poor performance contract.", "improving fund performance contract.", "improving land performance contract."
"improving human performance metrics." » "improving human performance contracts.", "improving human performance measures.", "improving loan performance metrics.", "improving thermal performance metrics.", "improving company performance metrics.", "improving urban performance metrics.", "improving rural performance metrics."

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