Perhaps you should try some spelling variations:
"central cgiar research forum series." » "central cgiar research focus series.", "central cgiar research from series.", "central cgiar research firm series.", "central asia research forum series.", "central asian research forum series.", "central chile research forum series."
"central city research forum series." » "central city research focus series.", "central city research from series.", "central city research firm series.", "central society research forum series.", "central equity research forum series.", "central key research forum series.", "central cities research forum series."

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

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"central cgiar research forum series.\") OR (\"central city research forum series.\"))~".
• Removing quotes may allow a broader search: (( central cgiar research forum series. ) OR ( central city research forum series. ))~.
• Adding a wildcard symbol may retrieve word variants: (("central cgiar research forum series.") OR ("central city research forum series."))*.