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   282987篇
  免费   5104篇
  国内免费   1852篇
电工技术   5718篇
技术理论   5篇
综合类   1201篇
化学工业   47136篇
金属工艺   11378篇
机械仪表   8147篇
建筑科学   7798篇
矿业工程   1755篇
能源动力   6148篇
轻工业   27453篇
水利工程   3077篇
石油天然气   6064篇
武器工业   243篇
无线电   29420篇
一般工业技术   53181篇
冶金工业   51181篇
原子能技术   5786篇
自动化技术   24252篇
  2021年   3004篇
  2020年   1986篇
  2019年   2522篇
  2018年   3886篇
  2017年   3793篇
  2016年   4275篇
  2015年   3319篇
  2014年   5256篇
  2013年   12659篇
  2012年   8757篇
  2011年   11563篇
  2010年   9087篇
  2009年   9606篇
  2008年   10516篇
  2007年   10547篇
  2006年   9273篇
  2005年   8057篇
  2004年   7323篇
  2003年   6784篇
  2002年   6699篇
  2001年   6701篇
  2000年   6237篇
  1999年   6228篇
  1998年   13528篇
  1997年   10029篇
  1996年   7670篇
  1995年   5883篇
  1994年   5410篇
  1993年   5270篇
  1992年   4181篇
  1991年   3924篇
  1990年   4055篇
  1989年   3999篇
  1988年   3723篇
  1987年   3203篇
  1986年   3253篇
  1985年   3637篇
  1984年   3511篇
  1983年   3256篇
  1982年   2878篇
  1981年   3062篇
  1980年   2778篇
  1979年   2996篇
  1978年   2876篇
  1977年   3004篇
  1976年   3898篇
  1975年   2592篇
  1974年   2398篇
  1973年   2411篇
  1972年   2066篇
排序方式: 共有10000条查询结果,搜索用时 11 毫秒
71.
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   
72.
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   
73.
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   
74.
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   
75.
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   
76.
77.
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   
78.
描述汽车显示器架构中的外部和内部接口及整合选型方案.  相似文献   
79.
Incremental data converters (IDCs) are useful in instrumentation and measurement applications, where low-frequency analog signals need to be converted into digital form with high accuracy and low power dissipation. They are particularly well suited for applications where a single analog-digital converter is multiplexed between many channels. This paper proposes an exact design methodology for IDCs, which optimizes the signal-to-noise ratio of the converter under practical design constraints. The process also allows the designer to apportion the noise budget in an arbitrary manner between thermal and quantization noise. The design process is illustrated by an example which describes the optimization of a third-order multiplexed IDC.  相似文献   
80.
This paper presents a new set of techniques for hardware implementations of Secure Hash Algorithm (SHA) hash functions. These techniques consist mostly in operation rescheduling and hardware reutilization, therefore, significantly decreasing the critical path and required area. Throughputs from 1.3 Gbit/s to 1.8 Gbit/s were obtained for the SHA implementations on a Xilinx VIRTEX II Pro. Compared to commercial cores and previously published research, these figures correspond to an improvement in throughput/slice in the range of 29% to 59% for SHA-1 and 54% to 100% for SHA-2. Experimental results on hybrid hardware/software implementations of the SHA cores, have shown speedups up to 150 times for the proposed cores, compared to pure software implementations.   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