"Clinical" means direct patient contact, whether you are talking about neurology, cardiology, endocrinology, or any other specialty. The other major branch of such specialties would be neurology research, cardiology research, etc. I work in a group of research pathology laboratories. At the same hospital there is a group of clinical pathology laboratories, involved in patient testing and diagnosis, using techniques originally developed in research laboratories.
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Clinical is like relating to a clinic or hospital. Regular neurology could be about researching neurology or teaching it.