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   395075篇
  免费   3210篇
  国内免费   469篇
电工技术   6365篇
综合类   277篇
化学工业   61344篇
金属工艺   24417篇
机械仪表   15113篇
建筑科学   7319篇
矿业工程   4833篇
能源动力   6688篇
轻工业   18305篇
水利工程   6358篇
石油天然气   16918篇
武器工业   31篇
无线电   34320篇
一般工业技术   95143篇
冶金工业   54638篇
原子能技术   14031篇
自动化技术   32654篇
  2021年   3524篇
  2019年   3466篇
  2018年   11790篇
  2017年   12160篇
  2016年   10659篇
  2015年   4192篇
  2014年   6900篇
  2013年   14319篇
  2012年   11339篇
  2011年   17067篇
  2010年   14792篇
  2009年   14735篇
  2008年   15229篇
  2007年   16208篇
  2006年   9086篇
  2005年   9872篇
  2004年   9099篇
  2003年   8830篇
  2002年   7917篇
  2001年   7330篇
  2000年   7223篇
  1999年   6572篇
  1998年   13032篇
  1997年   9986篇
  1996年   7479篇
  1995年   5920篇
  1994年   5421篇
  1993年   5613篇
  1992年   4658篇
  1991年   4755篇
  1990年   4861篇
  1989年   4672篇
  1988年   4567篇
  1987年   4433篇
  1986年   4362篇
  1985年   4563篇
  1984年   4404篇
  1983年   4292篇
  1982年   4019篇
  1981年   4210篇
  1980年   4141篇
  1979年   4424篇
  1978年   4735篇
  1977年   4798篇
  1976年   5755篇
  1975年   4338篇
  1974年   4388篇
  1973年   4465篇
  1972年   4054篇
  1971年   3688篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Filled fibrous sorbents modified with transition metal ferro- and ferricyanides capable to recover americium(III) and rare-earth metals(III) from nitric acid solutions were prepared. The most complete and rapid recovery is attained on complex-forming and cation-exchange sorbents (as filled fibrous materials) saturated with nickel ions. The sorbents are characterized by good kinetic properties and can be used for recovery of the above metals.  相似文献   
942.
A range of refractories is presented for handling steel outside a furnace, which are produced by the Borovichi Refractories Corporation. The refractory characteristics and working features are given. Translated from Novye Ogneupory, No. 9, pp. 29–35, September, 2008.  相似文献   
943.
Production methods used to prepare graphite crucibles with high operating properties are considered: use as a filler of good graphitizing acicular coke, vibration molding of the original coke mix, use of production cycles for impregnation with medium temperature coal-tar pitch — firing, firing of compacted billets in metal containers, graphitization of fired billets in graphite cylinders. The last two production methods make it possible to reduce the temperature drop throughout the volume of a billet during heat treatment, and as a consequence to reduce crack development to a minimum as a result of reducing thermal stresses. All of the production methods recommended may be entirely accomplished in existing electrode plants and may be used to increase markedly the quality crucible graphite. It is possible to achieve a quality for these materials at the best world level. Translated from Novye Ogneupory, No. 8, pp. 28–33, August 2008.  相似文献   
944.
Research results are given on magnesian box-type components in the tuyere belt of horizontal converters at Ufalei Nickel Corporation. The purpose has been to eliminate the zoning in them by impregnation with nickel or copper mattes to relieve thermal stresses during use. Components impregnated with matte show improved physicomechanical and thermophysical properties. A technology has been developed and tested for impregnating standard components under conditions found at Ufalei Nickel Corporation. Translated from Novye Ogneupory, No. 5, pp. 44–47, May, 2008.  相似文献   
945.
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   
946.
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   
947.
Secondary aluminum waste products, and processes that occur during heating and mineral formation on introducing fine periclase powder into the composition of waste products are studied. It is demonstrated that secondary aluminum production waste may be used as a raw material for synthesizing aluminomagnesia spinels. Translated from Novye Ogneupory, No. 6, pp. 15–18, June 2008.  相似文献   
948.
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   
949.
Nanocrystalline LaFeO3 is prepared by the dehydration of coprecipitated lanthanum and iron(III) hydroxides. It is shown that the behavior of the samples during heating and the size distribution of LaFeO3 nanocrystals can be considerably different depending on the scheme used for coprecipitation of lanthanum and iron hydroxides; independently of the method employed for coprecipitation of the initial compounds, sintering of the samples at 950°C leads to the formation of lanthanum orthoferrite crystals up to 100 nm in size.  相似文献   
950.
The composition and physicochemical properties of Gorlovsk Basin anthracite are studied, with a view to expanding its metallurgical use. In industrial tests, anthracite is employed in smelting hot metal in cupola furnaces, in the production of carbonized products and briquets, in ferroalloy production, in sintering iron ore, and in batch for foundry coke.  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