Perhaps you should try some spelling variations:
"improving sector performance studies." » "improving sector performance audits.", "improving sector performance audit.", "improving sector performance standards.", "improve sector performance studies.", "improving eco performance studies.", "improving sewer performance studies."
"improve 5 performance review." » "improve 5 performance risk.", "improve 5 performance evidence.", "improve 2 performance review.", "improve 3 performance review.", "improve _ performance review.", "improve a performance review.", "improve my performance review."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("improve 5 performance review.") OR ("improving sector performance studies."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improve 5 performance review.\") OR (\"improving sector performance studies.\"))*".
• Removing quotes may allow a broader search: (( improve 5 performance review. ) OR ( improving sector performance studies. ))*.