Perhaps you should try some spelling variations:
"natural and built environment resources." » "natural and built environment resource.", "natural and built environment sources.", "natural and built environmental resource."
"Natural and key environmental resources." » "Natural and 2 environmental resources.", "Natural and policy environmental resources."

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

• Performing a fuzzy search may retrieve terms with similar spellings: (("Natural and key environmental resources.") OR ("natural and built environment resources."))~.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"Natural and key environmental resources.\") OR (\"natural and built environment resources.\"))".
• Removing quotes may allow a broader search: (( Natural and key environmental resources. ) OR ( natural and built environment resources. )).
• Adding a wildcard symbol may retrieve word variants: (("Natural and key environmental resources.") OR ("natural and built environment resources."))*.