Perhaps you should try some spelling variations:
"smart and sustainable built environment" » "smart and sustainable city environment", "smart and sustainable debt environment", "smart and sustainable buildings environment", "start and sustainable built environment"
"Smart and sustainable solid environment" » "Smart and sustainable society environment", "Smart and sustainable solutions environment", "Smart and sustainable policy environment", "Smart and sustainable world environment", "Smart and sustainable road environment"

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

• If you are trying to use Boolean operators, they must be ALL CAPS: (("smart and sustainable built environment") OR ("Smart and sustainable solid environment"))~.
• Removing quotes may allow a broader search: (( smart and sustainable built environment ) or ( Smart and sustainable solid environment ))~.
• Adding a wildcard symbol may retrieve word variants: (("smart and sustainable built environment") or ("Smart and sustainable solid environment"))*.