Perhaps you should try some spelling variations:
"improving tool performance series." » "improving tool performance studies.", "improving tool performance size.", "improving total performance series.", "improving school performance series.", "improving model performance series.", "improving food performance series.", "improving toilet performance series."
"growing global performance series." » "growing global performance studies.", "growing global performance size.", "growing total performance series.", "growing regional performance series.", "growing general performance series.", "going global performance series."

Try widening your search to All Fields.

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("improving tool performance series.") or ("growing global performance series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improving tool performance series.") OR ("growing global performance series.")).
• Removing quotes may allow a broader search: (( improving tool performance series. ) or ( growing global performance series. )).
• Adding a wildcard symbol may retrieve word variants: (("improving tool performance series.") or ("growing global performance series."))*.