Perhaps you should try some spelling variations:
"central basic research _ series." » "central based research _ series.", "central asia research _ series.", "central bajio research _ series.", "neutral basic research _ series."
"central nodes research project survey." » "central modest research project survey.", "central does research project survey.", "central roles research project survey.", "central node research project survey.", "centrale des research project survey.", "central body research project survey.", "central nodes research projects survey."

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