Perhaps you should try some spelling variations:
"central basic research team series." » "central bank research team series.", "central asia research team series.", "central banks research team series.", "central basic research areas series.", "central basic research a series."
"central tax research firm surveys." » "central a research firm surveys.", "central bank research firm surveys.", "central _ research firm surveys.", "central tax research firm survey.", "central taxes research firm surveys."

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("central basic research team series.") OR ("central tax research firm surveys."))~.
• Removing quotes may allow a broader search: (( central basic research team series. ) or ( central tax research firm surveys. ))~.
• Adding a wildcard symbol may retrieve word variants: (("central basic research team series.") or ("central tax research firm surveys."))*.