首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   296442篇
  免费   6027篇
  国内免费   1862篇
电工技术   5667篇
技术理论   5篇
综合类   1195篇
化学工业   48730篇
金属工艺   11643篇
机械仪表   8398篇
建筑科学   7747篇
矿业工程   1726篇
能源动力   6321篇
轻工业   30376篇
水利工程   3195篇
石油天然气   6130篇
武器工业   247篇
无线电   29951篇
一般工业技术   55467篇
冶金工业   55692篇
原子能技术   5784篇
自动化技术   26057篇
  2021年   3265篇
  2020年   2322篇
  2019年   2726篇
  2018年   4719篇
  2017年   4685篇
  2016年   5072篇
  2015年   3759篇
  2014年   5847篇
  2013年   13775篇
  2012年   9762篇
  2011年   12141篇
  2010年   9647篇
  2009年   10032篇
  2008年   11086篇
  2007年   10987篇
  2006年   9487篇
  2005年   8262篇
  2004年   7504篇
  2003年   6952篇
  2002年   6872篇
  2001年   6709篇
  2000年   6300篇
  1999年   6387篇
  1998年   15505篇
  1997年   11134篇
  1996年   8324篇
  1995年   6159篇
  1994年   5629篇
  1993年   5486篇
  1992年   4141篇
  1991年   3946篇
  1990年   4024篇
  1989年   3960篇
  1988年   3703篇
  1987年   3171篇
  1986年   3219篇
  1985年   3607篇
  1984年   3481篇
  1983年   3197篇
  1982年   2841篇
  1981年   3053篇
  1980年   2789篇
  1979年   2967篇
  1978年   2848篇
  1977年   3003篇
  1976年   4057篇
  1975年   2548篇
  1974年   2363篇
  1973年   2389篇
  1972年   2028篇
排序方式: 共有10000条查询结果,搜索用时 9 毫秒
111.
The TELEMAC project brings new methodologies from the Information and Science Technologies field to the world of water treatment. TELEMAC offers an advanced remote management system which adapts to most of the anaerobic wastewater treatment plants that do not benefit from a local expert in wastewater treatment. The TELEMAC system takes advantage of new sensors to better monitor the process dynamics and to run automatic controllers that stabilise the treatment plant, meet the depollution requirements and provide a biogas quality suitable for cogeneration. If the automatic system detects a failure which cannot be solved automatically or locally by a technician, then an expert from the TELEMAC Control Centre is contacted via the internet and manages the problem.  相似文献   
112.
Polystyrene packaging material taint was sensorily evaluated in cocoa powder for drinks and chocolate flakes using short-cut signal detection measures on differences between control and test samples and on recognition of styrene. No differences were observed in cocoa powder for drinks and plain chocolate flakes treated with 0.5 dm2 polystyrene of 1 mm thickness. However, differences were detected in milk chocolate flakes and plain chocolate flakes, which were in contact with a larger area or thicker polystyrene packaging material. The latter results were confirmed by the styrene recognition test, so polystyrene is a potential source of off-flavour for chocolate products. The amount of residual styrene in the polystyrene used was about 320 ppm, while the amounts of styrene ranged from 7 to 132 ppb in cocoa drinks and from 414 to 1447 ppb in chocolate flakes.  相似文献   
113.
114.
Technology is developed for preparing refractory components made of partially stabilized zirconium dioxide using an isostatic compaction press. Technology is provided for manufacturing dispensing nozzles using combined and separately stabilized zirconium dioxide, and also indices of the refractories obtained and imported materials are compared. __________ Translated from Novye Ogneupory, No. 3, pp. 127–131, March 2008.  相似文献   
115.
Compositions have been developed for nonshrinking vibrocast thermally insulating light refractory concretes with densities of 1.0, 1.3, 1.5, and 1.8 g/cm3 for temperatures of use up to 1400°C. The structure and properties have been examined for the concrete of density 1.3 g/cm3. __________ Translated from Novye Ogneupory, No. 4, pp. 29–32, April, 2008.  相似文献   
116.
Methods are proposed for designing interpolation models for the preliminary determination and subsequent forecasting of general and fractional breakthrough coefficients for dust used with granular filters, as employed in energy-saving and high-performance dust trapping from technological gases and ventilation discharges in refractory production. The models are supplied with nomograms, which makes them widely suitable for experts working in environmental protection at refractory-producing organizations. The main factors are identified that influence the performance. The results are of interest to experts in related areas of industry such as building materials and engineering ceramics and so on. Translated from Novye Ogneupory, No. 4, pp. 64–67, April, 2008.  相似文献   
117.
Results are presented on the corrosion resistance of chromium-bearing refractories of granular structure acted on by corrosive molten slags, metals, and glasses. It is possible to recommend these refractories to customers for particular conditions of use. Chromium-bearing refractories increase the working lives of furnaces considerably. __________ Translated from Novye Ogneupory, No. 1, pp. 55–61, January, 2008.  相似文献   
118.
The aggregate stability of submicron and nanosized ZrO2 aqueous sols of different origins and different dispersities at pH 3–10 in the KCl concentration range 10?3–10?1 M is investigated by flow ultramicroscopy and photometry. The results obtained are analyzed in the framework of the extended Derjaguin-Landau-Verwey-Overbeek theory and the Muller-Martynov theory of reversible aggregation. The extension of boundary layers of water near the surface of the ZrO2 particles is estimated.  相似文献   
119.
120.
Results are provided for a study of the microstructure of ceramics from four different producers by means of a scanning electron microscope and x-ray microanalysis. Results show that ceramic specimens often do not correspond to claimed parameters. The main disadvantages are ceramic structural inhomogeneity, presence of phases of a different nature, intergranular pores and cracks, and alkali impurities. The ceramics of only one producer correspond to the main parameters for this class, and this is provided by high production technology and starting material quality. Translated from Novye Ogneupory, No. 7, pp. 31–35, July 2008.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号