Access requires a personal account CAS SciFindern includes reference, reaction, substance results, step-by-step procedures and protocols, citation mapping, biosequence searching, retrosynthetic analysis, touch-screen enabled structure drawing and much more.
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PubChem mostly contains small molecules, but also larger molecules such as nucleotides, carbohydrates, etc. Info on structures, identifiers, chemical and physical properties, biological activities, health, safety, toxicity, and others.