Perhaps you should try some spelling variations:
"improving contract performance evidence." » "improving country performance evidence.", "improving court performance evidence.", "improving economic performance evidence.", "improve contract performance evidence.", "improving central performance evidence.", "improve contrast performance evidence."
"improving larval performance series." » "improving level performance series.", "improving thermal performance series.", "improving maximal performance series.", "improving larval performance studies.", "improving larval performance size.", "improving local performance series.", "improving legal performance series.", "improving land 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 contract performance evidence.") or ("improving larval performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving contract performance evidence.") OR ("improving larval performance series.")).
• Removing quotes may allow a broader search: (( improving contract performance evidence. ) or ( improving larval performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving contract performance evidence.") or ("improving larval performance series."))*.