Perhaps you should try some spelling variations:
"improving social performance contract." » "improving social performance contracts.", "improving school performance contract.", "improving fiscal performance contract.", "improving financial performance contract."
"improving human performance series." » "improving human performance metrics.", "improving human performance reviews.", "improving human performance review.", "improving loan performance series.", "improving thermal performance series.", "improving company performance series.", "improving urban performance series.", "improving rural performance series."

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 series.") or ("improving social performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving human performance series.") OR ("improving social performance contract."))*.
• Removing quotes may allow a broader search: (( improving human performance series. ) or ( improving social performance contract. ))*.