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"Science.gov searches over 60 databases and over 2200 selected websites from 15 federal agencies, offering 200 million pages of authoritative U.S. government science information including research and development results."
SciTech Connect is a portal to free, publicly-available DOE-sponsored R&D results including technical reports, bibliographic citations, journal articles, conference papers, books, multimedia and data information. SciTech Connect is a consolidation of two core DOE search engines, the Information Bridge and the Energy Citations Database. SciTech Connect incorporates all of the R&D information from these two products into one search interface. SciTech Connect was developed by the U.S. Department of Energy (DOE) Office of Scientific and Technical Information (OSTI) to increase access to science, technology, and engineering research information from DOE and its predecessor agencies.
The USGS is a science organization that provides impartial information on the health of our ecosystems and environment, the natural hazards that threaten us, the natural resources we rely on, the impacts of climate and land-use change, and the core science systems that help us provide timely, relevant, and usable information.
These are general-use maps at medium scales that present elevation (contour lines), hydrography, geographic place names, and a variety of cultural features. Current-generation topographic maps are created from digital GIS databases, and are branded "US Topo." Historic maps originally published as paper documents in the period 1884-2006 are available as scanned images.