Perhaps you should try some spelling variations:
"central basic research data series." » "central based research data series.", "central asia research data series.", "central bajio research data series.", "neutral basic research data series.", "central basic research data services.", "central basic research data queries.", "central basic research data species."
"central a research team surveys." » "central a research firm surveys.", "central a research from surveys.", "central a research team success.", "central 2 research team surveys.", "central la research team surveys.", "central _ research team surveys.", "central 1 research team surveys."

Try widening your search to All Fields.

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

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