Perhaps you should try some spelling variations:
"central cgiar research firm surveys." » "central asia research firm surveys.", "central asian research firm surveys.", "central chile research firm surveys.", "central cgiar research field surveys.", "central cgiar research final surveys.", "central cgiar research firm survey."
"central city research from series." » "central society research from series.", "central equity research from series.", "central key research from series.", "central cities research from series.", "central city research rom series.", "central city research from services.", "central city research forum series."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("central cgiar research firm surveys.") or ("central city research from series."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("central cgiar research firm surveys.") OR ("central city research from series.")).
• Removing quotes may allow a broader search: (( central cgiar research firm surveys. ) or ( central city research from series. )).
• Adding a wildcard symbol may retrieve word variants: (("central cgiar research firm surveys.") or ("central city research from series."))*.