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Library of Congress
The Library of Congress. The Library of Congress is the nation\'s oldest federal cultural institution, and it serves as the research arm of Congress. It is also the largest library in the world, with more than 120 million items. The collections include books, sound recordings, motion pictures, photographs, maps, and manuscripts
点击进入 - 2015-03-20 - 收藏
Welcome to the USGS - U.S. Geological Survey
Federal source for science about the Earth, its natural and living resources, natural hazards, and the environment.
点击进入 - 2014-02-04 - 收藏
Khan Academy
Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.
点击进入 - 2014-05-22 - 收藏
Huffington Post
The destination for news, blogs and original content offering coverage of US politics, entertainment, style, world news, technology and comedy - Huffington Post
点击进入 - 2015-09-03 - 收藏
MetroLyrics
MetroLyrics is a searchable lyrics database featuring 1,000,000+ song lyrics from 20,000 artists. Use MetroLyrics to find your forite song lyrics.
点击进入 - 2014-11-28 - 收藏
TechCrunch科技
TechCrunch is a leading technology media property, dedicated to obsessively profiling startups, reviewing new Internet products, and breaking tech news.
点击进入 - 2013-11-17 - 收藏
