This page will outline how best to access regulations currently in effect on the Federal and State (Michigan) level. Regulations are the published, binding, primary law for Administrative Law research so they ought to be your guide. They are written and published via a process mandated by statute. The Federal statute describing this process is the Administrative Procedures Act, 5 U.S.C. § 500 et. seq., and Michigan's equivalent is also called the Administrative Procedures Act, MCL § 24.291 et seq.
After their publication, regulations are arranged in a continuously updated Code with a format similar to statutes. Federal regulations are published in the Code of Federal Regulations and Michigan regulations are published in the Michigan Administrative Code. While these Codes appear to simply arrange regulations by subject, they actually arrange them by agency. For instance, with Title 7 of the CFR (dealing with agriculture), Sections 210-299 are reserved for the Food and Nutrition Service, 300-399 are for the Animal and Plant Health Inspection Service, 400-499 are for the Federal Crop Insurance Program, and so forth. The Michigan Administrative Code takes this a step further with a formal top-level organization scheme built explicitly around the various Executive departments it represents rather than numeric citation (though such citation exists at the section level).
What this means in practice is that it is always preferable to understand what agency has regulatory authority over your issue so that you can proceed directly to their delegated section of the Code rather than trying to search the Code blind. This can be accomplished in a number of ways, most notably through the enabling statute. Note that while LexisNexis and Westlaw do provide copies of these Codes, they are not annotated in the way we expect with statutes, as regulations are prone to rapid change and rarely get enough analysis in the courts to generate such annotations.