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   1426篇
  免费   10篇
电工技术   12篇
化学工业   155篇
金属工艺   47篇
机械仪表   57篇
建筑科学   6篇
矿业工程   28篇
能源动力   9篇
轻工业   15篇
水利工程   11篇
石油天然气   59篇
无线电   299篇
一般工业技术   143篇
冶金工业   506篇
原子能技术   62篇
自动化技术   27篇
  2021年   15篇
  2019年   9篇
  2018年   12篇
  2017年   16篇
  2016年   18篇
  2015年   8篇
  2014年   22篇
  2013年   27篇
  2012年   25篇
  2011年   32篇
  2010年   31篇
  2009年   24篇
  2008年   21篇
  2007年   27篇
  2006年   19篇
  2005年   24篇
  2003年   21篇
  2002年   21篇
  2001年   64篇
  2000年   71篇
  1999年   63篇
  1998年   172篇
  1997年   140篇
  1996年   49篇
  1995年   27篇
  1994年   38篇
  1993年   28篇
  1992年   14篇
  1991年   21篇
  1990年   21篇
  1989年   12篇
  1988年   17篇
  1987年   14篇
  1986年   12篇
  1985年   13篇
  1984年   7篇
  1982年   13篇
  1981年   15篇
  1980年   10篇
  1979年   8篇
  1978年   11篇
  1977年   34篇
  1976年   55篇
  1975年   10篇
  1974年   13篇
  1973年   17篇
  1972年   15篇
  1971年   17篇
  1970年   9篇
  1967年   8篇
排序方式: 共有1436条查询结果,搜索用时 15 毫秒
41.
42.
Preliminary data analysis in the identification of multidimensional discrete–continuous processes is considered. A method is proposed for generating a working sample from an initial training sample consisting of normal operating data. The method somewhat resembles the bootstrap process. In the present case, the process begins with a training sample that reflects the properties of the object to be identified. By means of the proposed method, the unknown stochastic dependence at the limit of definition of the corresponding input–output variables for the object may be automatically derived. The identification of the oxygen-converter process in converter shop 2 at OAO EVRAZ ZSMK is considered in the case with insufficient available information and gaps in the observation sample. The model is based on a new working sample containing both the measurements and data generated by the proposed method. By using the working sample as a training sample, the precision of identification is doubled.  相似文献   
43.
44.
45.
46.
Russian Journal of Nondestructive Testing - To increase the speed of recording of echo signals and increase the speed of reconstruction of the image of reflectors, it is proposed to use a sparse...  相似文献   
47.
Absract The effect of electrical blast parameters is studied for grinding mineral materials by example of copper-nickel ore. It is shown that the average energy consumed by the electrical blasting is within 5–50 J/g. The particle disintegration mechanism has been considered at high and low electric conductivity of ore. It is established that grinding and separation of particles by size are possible to be performed conjointly in the same apparatus. __________ Translated from Fiziko-Tekhnicheskie Problemy Razrabotki Poleznykh Iskopaemykh, No. 1, pp. 100–107, January–February, 2007.  相似文献   
48.
High-temperature proton conductors based on acceptor-doped barium zirconate exhibit excellent chemical stability in atmospheres containing CO2 or H2O. However, due to their refractory nature, these conductors have a low grain growth rate, which negatively affects the overall electrical conductivity. A possible strategy for increasing the ionic conductivity of zirconates lies in the partial substitution of Zr-ions with other isovalent dopants. In this work, we carried out systematic studies of the crystal structure, microstructure, hydration capacity, transport, and thermal properties of BaZr0.8–xSnxSc0.2O3–δ (x = 0, 0.1, and 0.2). According to X-ray powder diffraction and scanning electron microscopy data, all studied ceramic samples have a cubic perovskite structure, whose average grain size decreases with tin doping. It is found that the composition with x = 0.1 exhibits the highest values in terms of total, ionic, grain, and grain-boundary conductivities. The complex analysis of the obtained data shows that a low-level substitution of Zr4+- with Sn4+-ions is a competent approach for designing new proton-conducting electrolytes attractive for high-temperature applications.  相似文献   
49.
Thermal conditions for the additive manufacture of components by melting metal and alloy wire are presented. In an experiment, a prototype 3D printer is used to print components in vacuum.  相似文献   
50.
The author analyzes certain parameters determining the structure of glasses, which ought to be taken into account in developing chemical compositions for microspheres, namely, the molar volume, the silicate modulus (for silicate glasses), the gas permeability coefficient, and the structure coherence factor. Furthermore, the parameter of internal porosity is proposed.  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