Best of the Web
Free online access to databases related to many scientific disciplines including chemistry, biology, and physics.
Global Science Portal. WorldWideScience.org was developed by the Energy Department and the British Library, along with science and technology organizations in Australia, Brazil, Canada, Denmark, France, Germany, Japan and the Netherlands. It employs federated search technology a search method that simultaneously executes a query against an array of databases, then aggregates and ranks the results and gives users a single entry point for searching far-flung science portals in parallel with only one query.