Perhaps you should try some spelling variations:
"central basic research a series." » "central based research a series.", "central asia research a series.", "central bajio research a series.", "neutral basic research a series."
"central taxes research food survey." » "central tables research food survey.", "central tax research food survey.", "central wages research food survey.", "central banks research food survey.", "federal taxes research food survey.", "central taxes research from survey.", "central taxes research fund survey.", "central taxes research focus survey.", "central taxes research hold survey.", "central taxes research field survey.", "central taxes research food sources."

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