"Civil online CO (the former netease civil online) is a civil engineering industry vertical sites, since founded in 2002, after years of development, has become the hvac, refrigeration, water supply and drainage, architectural, structural, electrical, landscape, environmental protection, water conservancy, road and bridge top ten channels in the industry's biggest exchange platform, covers all the small kind to civil engineering and construction industry. CO civil online civil online more than 17 million people registered users, users more than 100 enterprises, a large number of professionals and engineers are discussed in this engineering technology, cutting-edge technology, learning problems, such as BBS quantity more than 10000 daily post CO civil is the industry's biggest online information sharing platform, including drawings, paper, software, all kinds of industry standards, electronic books, recruitment, etc. HVAC channel is the main civil online classified channel, positioning in the HVAC industry professional database and professional technology exchange platform, strive to provide professional services and provide more accurate business opportunities for engineers and enterprises in the HVAC industry.