umls-concept:C0220806 | skos:definition | CSP: tree section heading for terms covering drugs, reagents, biomolecules, and other chemical compounds.,NCI: A substance with a defined atomic or molecular structure that results from, or takes part in, reactions involving changes in its structure, composition, or properties.,NCI: A substance made up of elements, such as hydrogen or sodium.,HL7V3.0: <p>A substance that is fully defined by an organic or inorganic chemical formula, includes mixtures of other chemical substances. Refine using, e.g., IUPAC codes.</p> | lld:umls |