Perhaps you should try some spelling variations:
"central led research project risk." » "central field research project risk.", "central based research project risk.", "central food research project risk.", "centrally led research project risk.", "central de research project risk.", "central la research project risk."
"central tax research project ii." » "central 2 research project ii.", "central 2.1 research project ii.", "central 2.2 research project ii.", "central taxes research project ii.", "central bank research project ii.", "central tax research project id.", "central tax research projekt ii.", "central tax research project ifd."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("central led research project risk.") or ("central tax research project ii."))~.
• If you are trying to use Boolean operators, they must be ALL CAPS: (("central led research project risk.") OR ("central tax research project ii."))*.
• Removing quotes may allow a broader search: (( central led research project risk. ) or ( central tax research project ii. ))*.