Perhaps you should try some spelling variations:
"improving do performance contract." » "improving do performance contracts.", "improving job performance contract.", "improving low performance contract.", "improving _ performance contract.", "improving co performance contract.", "improving food performance contract."
"improved land performance series." » "improved land performance metrics.", "improved land performance reviews.", "improved land performance review.", "improved plant performance series.", "improved bank performance series.", "improved loan performance series.", "improve 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: (("improved land performance series.") or ("improving do performance contract."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("improved land performance series.") OR ("improving do performance contract."))*.
• Removing quotes may allow a broader search: (( improved land performance series. ) or ( improving do performance contract. ))*.