*Chemistry

"Science.gov searches over 60 databases and over 2,200 scientific websites to provide users with access to more than 200 million pages of authoritative federal science information including research and development results. "

"arXiv is a free distribution service and an open-access archive for 2,158,138 scholarly articles in the fields of physics, mathematics, computer science, quantitative biology, quantitative finance, statistics, electrical engineering and systems science, and economics. Materials on this site are not peer-reviewed by arXiv. "

"Founded in 2002 by Nobel Laureate Carl Wieman, the PhET Interactive Simulations project at the University of Colorado Boulder creates free interactive math and science simulations. PhET sims are based on extensive education research and engage students through an intuitive, game-like environment where students learn through exploration and discovery."

Unpublished preprints in chemistry (not peer reviewed)

"Virtual Chemistry created, designed & maintained by final year MChem research students in the Department of Chemistry, University of Oxford Copyright 1996-2005"

"Polymer Database "PoLyInfo" systematically provides various data required for polymeric material design. The main data source is academic literature on polymers. Information on polymers including properties, chemical structures, IUPAC names, processing methods of measured samples, measurement conditions, used monomers and polymerization methods are stored in a object database. About 100 types of properties including thermal, electrical and mechanical properties are covered. Homopolymers, copolymers, furthermore polymer blends, composites and compounds that consist of homopolymers and copolymers are open to the public. "

"ChemSynthesis is a freely accessible database of chemicals. This website contains substances with their synthesis references and physical properties such as melting point, boiling point and density. There are currently more than 40,000 compounds and more than 45,000 synthesis references in the database."

"This site provides thermochemical, thermophysical, and ion energetics data compiled by NIST under the Standard Reference Data Program."

"SDBS is an integrated spectral database system for organic compounds,which includes 6 different types of spectra under a directory of the compounds"

Collection of various types of calculators, from math to finance to fitness.

Online conversions calculator for a variety of unit measurements featuring natural language queries.

Trigonometry, matrices, complex numbers, unit conversion and more.

"iScienceSearch is a federated search service that retrieves chemical compound information from a wide variety of databases (sources) on the Internet. It is a two step process. If the users starts with a structure, identifier (synonym, CAS #, AKos number, SMILES, etc.) iScienseSearch tries to find in two sources alternative synonyms, and identifiers. When the user clicks on "SEARCH", we start in the background parallel sometimes several hundred searches. In spite of this you get answers quickly, and you don't have to wait until all the results are presented. "

"ChemSpider is a free chemical structure database providing fast text and structure search access to over 100 million structures from hundreds of data sources."

"Students, teachers and researchers in an academic settings can—at no charge—download BIOVIA Draw for rapidly drawing chemical structures and chemically intelligent queries."

"Free Software for Drawing Chemical Structures ChemSketch is our popular structure drawing software with over 2 million downloads worldwide."

"UCSF ChimeraX (or simply ChimeraX) is the next-generation molecular visualization program from the Resource for Biocomputing, Visualization, and Informatics (RBVI), following UCSF Chimera. ChimeraX can be downloaded free of charge for academic, government, nonprofit, and personal use."

"Open Babel is a chemical toolbox designed to speak the many languages of chemical data. It's an open, collaborative project allowing anyone to search, convert, analyze, or store data from molecular modeling, chemistry, solid-state materials, biochemistry, or related areas."

"Pybel provides convenience functions and classes that make it simpler to use the Open Babel libraries from Python, especially for file input/output and for accessing the attributes of atoms and molecules. The Atom and Molecule classes used by Pybel can be converted to and from the OBAtom and OBMol used by the openbabel module. These features are discussed in more detail below."

"With CellPAINT, you can create dynamic illustrations of the inner molecular structure of viruses and living cells. CellPAINT pictures are based on experimental results from many different laboratories. The size and shape of each molecule is based on atomic structures determined by x-ray crystallography, NMR spectroscopy and electron microscopy, and key interactions, such as the embedding of proteins in membranes, are enforced as you create your pictures."

"Created in 2000 by Pesticide Action Network (PAN) North America, the Pesticide Info database is a one-of-a-kind resource that combines publicly available data to create an interactive, searchable database of every chemical and product related to pesticide use and application. This unique online tool brings together a diverse array of information on pesticides from many sources, providing human toxicity (chronic and acute), ecotoxicity and regulatory information and more for about 15,300 pesticide active ingredients and their transformation products, including solvents and other additives used in pesticide products."

"The NBI Knowledgebase is intended to offer industry, academia, the general public, and regulatory agencies a mechanism to rationally inquire for unbiased interpretation of nanomaterial exposure effects in biological systems."

"Rapid access to internationally peer reviewed information on chemicals published through the International Programme on Chemical Safety (IPCS). All types of chemicals from the full range of exposure situations (environment, food, occupational) are included. Searching across all collections or within individual collections is available."

"Columbia University's Center for the History and Ethics of Public Health, located at its Mailman School of Public Health, and the City University of New York's Graduate Center are proud to jointly present ToxicDocs. This dataset and website contain millions of pages of previously secret documents about toxic substances. They include secret internal memoranda, emails, slides, board minutes, unpublished scientific studies, and expert witness reports -- among other kinds of documents -- that emerged in recent toxic tort litigation."

"DSSTox provides a high quality public chemistry resource for supporting improved predictive toxicology. A distinguishing feature of this effort is the accurate mapping of bioassay and physicochemical property data associated with chemical substances to their corresponding chemical structures.  "

"CAMEO Chemicals is a database of hazardous chemical datasheets that emergency responders and planners can use to get response recommendations and predict hazards—such as explosions or toxic fumes."

"The Agency for Toxic Substances and Disease Registry (ATSDR), based in Atlanta, Georgia, is a federal public health agency of the U.S. Department of Health and Human Services. ATSDR protects communities from harmful health effects related to exposure to natural and man-made hazardous substances."

"The CompTox Chemicals Dashboard is a part of a suite of databases and web applications developed by the US Environmental Protection Agency. These databases and apps support EPA's research efforts to develop and apply new approach methods (NAMs) to EPA researchers integrate advances in biology, bioinformatics, biotechnology, chemistry, and computer science to identify important biological processes that may be disrupted by the chemicals."

"free resource for searching databases on toxicology, hazardous chemicals, and environmental health."