Perhaps you should try some spelling variations:
"3 regulatory perspectives" » "3 regulatory perspective", "3 regulation perspectives"
"key regulatory peptides" » "key regulatory regimes", "key regulator peptides", "key regulators peptides", "4 regulatory peptides"

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: (("key regulatory peptides") OR ("3 regulatory perspectives"))*.
• Removing quotes may allow a broader search: (( key regulatory peptides ) or ( 3 regulatory perspectives ))*.