Scopus
Indexes most peer reviewed journals in science, technology, and medicine, and many in the social sciences, arts, and humanities. Scopus also includes a number of trade publications and conference papers, and can perform author and affiliation searching.
Holdings: 1823-present, although most records are from 1996 or later.

Reaxys
Reaxys is one of the largest handbooks of substances, their properties, and their reactions, combining data from three sources, the Beilstein Handbook of Organic Chemistry, the Gmelin Handbook of Inorganic Chemistry, and the Elsevier Patent Chemistry Database. It includes organic, inorganic, and organometallic substances and indexes more than 800 different physical and chemical properties, many of which have values available directly in the database. Reactions include reagents, catalysts and conditions, and all records link back to articles in the primary literature. The Synthesis Planner feature allows researchers to generate a synthetic procedure and organize the articles that report the various steps in a single place.