全文获取类型
收费全文 | 300684篇 |
免费 | 3848篇 |
国内免费 | 1338篇 |
专业分类
电工技术 | 5104篇 |
综合类 | 554篇 |
化学工业 | 45399篇 |
金属工艺 | 11478篇 |
机械仪表 | 8836篇 |
建筑科学 | 7636篇 |
矿业工程 | 1671篇 |
能源动力 | 7526篇 |
轻工业 | 24130篇 |
水利工程 | 3242篇 |
石油天然气 | 5838篇 |
武器工业 | 43篇 |
无线电 | 35102篇 |
一般工业技术 | 60408篇 |
冶金工业 | 55038篇 |
原子能技术 | 7669篇 |
自动化技术 | 26196篇 |
出版年
2021年 | 2674篇 |
2020年 | 1937篇 |
2019年 | 2458篇 |
2018年 | 4069篇 |
2017年 | 4088篇 |
2016年 | 4493篇 |
2015年 | 2997篇 |
2014年 | 5032篇 |
2013年 | 13262篇 |
2012年 | 8109篇 |
2011年 | 11083篇 |
2010年 | 8510篇 |
2009年 | 9682篇 |
2008年 | 10150篇 |
2007年 | 10116篇 |
2006年 | 8663篇 |
2005年 | 7923篇 |
2004年 | 7881篇 |
2003年 | 7568篇 |
2002年 | 7223篇 |
2001年 | 7222篇 |
2000年 | 6797篇 |
1999年 | 7128篇 |
1998年 | 16963篇 |
1997年 | 12065篇 |
1996年 | 9302篇 |
1995年 | 7206篇 |
1994年 | 6347篇 |
1993年 | 6377篇 |
1992年 | 4644篇 |
1991年 | 4354篇 |
1990年 | 4323篇 |
1989年 | 4279篇 |
1988年 | 3945篇 |
1987年 | 3595篇 |
1986年 | 3604篇 |
1985年 | 3990篇 |
1984年 | 3663篇 |
1983年 | 3411篇 |
1982年 | 3215篇 |
1981年 | 3216篇 |
1980年 | 3185篇 |
1979年 | 3012篇 |
1978年 | 3020篇 |
1977年 | 3314篇 |
1976年 | 4308篇 |
1975年 | 2557篇 |
1974年 | 2493篇 |
1973年 | 2493篇 |
1972年 | 2106篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
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
102.
Yunlei Li Dick de Ridder Robert P.W. Duin Marcel J.T. Reinders 《Pattern recognition》2008,41(1):320-330
Samples can be measured with different precisions and reliabilities in different experiments, or even within the same experiment. These varying levels of measurement noise may deteriorate the performance of a pattern recognition system, if not treated with care. Here we seek to investigate the benefit of incorporating prior knowledge about measurement noise into system construction. We propose a kernel density classifier which integrates such prior knowledge. Instead of using an identical kernel for each sample, we transform the prior knowledge into a distinct kernel for each sample. The integration procedure is straightforward and easy to interpret. In addition, we show how to estimate the diverse measurement noise levels in a real world dataset. Compared to the basic methods, the new kernel density classifier can give a significantly better classification performance. As expected, this improvement is more obvious for small sample size datasets and large number of features. 相似文献
103.
V. Ya. Sakulin V. P. Migal’ A. P. Margishvili V. V. Bulin 《Refractories and Industrial Ceramics》2008,49(5):354-358
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
104.
I. D. Kashcheev S. N. Sychev M. N. Dunaeva L. A. Karpets P. A. Emel’yanov O. S. Ryakhova 《Refractories and Industrial Ceramics》2008,49(2):131-134
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
105.
A. A. Man’kov Yu. V. Krasovitskii E. V. Arkhangel’skaya S. L. Kabargin D. B. Troshchenko N. N. Lobacheva V. P. Dobrosotskii 《Refractories and Industrial Ceramics》2008,49(3):225-228
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
106.
107.
108.
B. L. Krasnyi V. P. Tarasovskii A. B. Krasnyi A. L. Kuteinikova 《Refractories and Industrial Ceramics》2008,49(1):57-62
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
109.
V. A. Mozhzherin V. Ya. Sakulin V. P. Migal’ A. P. Margishvili A. A. Konstantinov 《Refractories and Industrial Ceramics》2008,49(4):245-250
In the OAO Borovich Refractory Combine production has been assimilated for a complete set of refractories for continuous steel
casting, i.e. from a pipe for protecting a stream of metal to a submerged nozzle. In technical and life characteristics the
products correspond to that of world analogs, they provide accident free steel pouring, make it possible to reduce the specific
consumption of refractories per ton of steel, to increase CBCM productivity, to reduce billet scrap, and to reduce steel cost.
Translated from Novye Ogneupory, No. 8, pp. 4–9, August 2008. 相似文献
110.
Phase transitions are considered for silicon oxycarbide material between joints in hearth blocks under aluminum electrolyzer
operating conditions. It is established that in the electrolyzer there is formation of aluminum subcarbide, and also there
is conversion of silicon carbide polytypes as a result of impurities of aluminum, sodium, magnesium, copper and iron. Due
to phase transitions there is a reduction in joint strength, and therefore it is undesirable to use material based on corundum
and black silicon carbide in hearth joints between blocks for aluminum electrolyzers. Use of pure α-SiO2 free from impurities is recommended for this purpose.
Translated from Novye Ogneupory, No. 4, pp. 47–52, April 2008. 相似文献