Perhaps you should try some spelling variations:
"key regulatory perspectives" » "key regulatory perspective", "key regulator perspectives", "key regulators perspectives", "3 regulatory perspectives"
"a regulatory properties" » "a regularity properties", "a regular properties", "a regulatory proteins"
"key regulatory peptides" » "key regulatory regimes", "key regulator peptides", "key regulators peptides", "3 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 perspectives") OR ("key regulatory peptides"))) OR ("a regulatory properties"))*.
• The words AND, OR and NOT may confuse the search; try adding quotes: "((((\"key regulatory perspectives\") OR (\"key regulatory peptides\"))) or (\"a regulatory properties\"))*".
• Removing quotes may allow a broader search: (((( key regulatory perspectives ) OR ( key regulatory peptides ))) or ( a regulatory properties ))*.