Perhaps you should try some spelling variations:
performance contract » performance contracts
performance series » performance studies, performance size
poor performance » sector performance
improving poor » improving power, improving food, improving peer
co performance » ceo performance, do performance, core performance
improving co » improving eco, improving crop, improving ict

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

• Performing a fuzzy search may retrieve terms with similar spellings: (( improving poor performance series. ) or ( improving co performance contract. ))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (( improving poor performance series. ) OR ( improving co performance contract. )).
• Adding a wildcard symbol may retrieve word variants: (( improving poor performance series. ) or ( improving co performance contract. ))*.