PubChem

**Semantic type:** Intellectual Product

**Definition:** Maintained by the National Center for Biotechnology Information (NCBI). Provides information on the chemical activity of small molecules and encompasses three primary databases: PCSubstance, which contains over 10 million records of substance information; PCCompound, which contains over 5 million unique component structures, and PCBioAssay, which contains over 190 million bioassays and bioactivity data.