Successful subject searching
In some instances, regulation can be used as part of the subject string eg Trade regulation or Foreign trade regulation
In other areas, it is best not to use it and just the more general term eg Antitrust law or Banking law or Government purchasing or Financial risk management
If you are interested in the regulation of a specific sectors try adding (according to which best reflect your research interests)
Law and legislation, Government policy, State supervision, Economic aspects, even perhaps Safety regulations to the sector or industry.
For example: Financial Services Industry -- law and legislation; Financial institutions -- law and legislation; International Finance law and legislation; Professional sports -- law and legislation; Public utilities -- Law and legislation; Public utilities -- Government policy; Public utilities -- Economic aspects; Public utilities --State supervision