Perhaps you should try some spelling variations:
"improving indoor performance series." » "improving indoor performance studies.", "improving indoor performance size.", "improving outdoor performance series.", "improving donor performance series.", "improving floor performance series.", "improving india's performance series.", "improving food performance series.", "improving gender performance series."
"improving poor performance series." » "improving poor performance studies.", "improving poor performance size.", "improving sector performance series.", "improving power performance series.", "improving food performance series.", "improving peer 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 indoor performance series.") OR ("improving poor performance series."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"improving indoor performance series.\") OR (\"improving poor performance series.\"))".
• Removing quotes may allow a broader search: (( improving indoor performance series. ) OR ( improving poor performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving indoor performance series.") OR ("improving poor performance series."))*.