Perhaps you should try some spelling variations:
"improving bank performance series." » "improving bank performance metrics.", "improving bank performance reviews.", "improving bank performance review.", "improving market performance series.", "improving _ performance series.", "improving firm performance series.", "improving land performance series.", "improving urban performance series.", "improving basic performance series."
"improving human performance risk." » "improving loan performance risk.", "improving thermal performance risk.", "improving company performance risk.", "improving human performance size.", "improving human performance based.", "improving human performance _.", "improving urban performance risk.", "improving rural performance risk."

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