全文获取类型
收费全文 | 331315篇 |
免费 | 2638篇 |
国内免费 | 672篇 |
专业分类
电工技术 | 4793篇 |
综合类 | 2407篇 |
化学工业 | 51616篇 |
金属工艺 | 19831篇 |
机械仪表 | 13035篇 |
建筑科学 | 6320篇 |
矿业工程 | 4318篇 |
能源动力 | 4992篇 |
轻工业 | 13213篇 |
水利工程 | 5319篇 |
石油天然气 | 13344篇 |
武器工业 | 28篇 |
无线电 | 29276篇 |
一般工业技术 | 78529篇 |
冶金工业 | 34688篇 |
原子能技术 | 11385篇 |
自动化技术 | 41531篇 |
出版年
2021年 | 2802篇 |
2019年 | 2755篇 |
2018年 | 19591篇 |
2017年 | 18776篇 |
2016年 | 15841篇 |
2015年 | 3659篇 |
2014年 | 5554篇 |
2013年 | 10294篇 |
2012年 | 10396篇 |
2011年 | 18140篇 |
2010年 | 15421篇 |
2009年 | 13544篇 |
2008年 | 14817篇 |
2007年 | 15496篇 |
2006年 | 6491篇 |
2005年 | 6745篇 |
2004年 | 6574篇 |
2003年 | 6448篇 |
2002年 | 5667篇 |
2001年 | 5049篇 |
2000年 | 5119篇 |
1999年 | 4309篇 |
1998年 | 7227篇 |
1997年 | 5861篇 |
1996年 | 4465篇 |
1995年 | 3669篇 |
1994年 | 3436篇 |
1993年 | 3635篇 |
1992年 | 3233篇 |
1991年 | 3386篇 |
1990年 | 3481篇 |
1989年 | 3372篇 |
1988年 | 3279篇 |
1987年 | 3262篇 |
1986年 | 3161篇 |
1985年 | 3317篇 |
1984年 | 3256篇 |
1983年 | 3151篇 |
1982年 | 2993篇 |
1981年 | 3048篇 |
1980年 | 3072篇 |
1979年 | 3258篇 |
1978年 | 3495篇 |
1977年 | 3467篇 |
1976年 | 3921篇 |
1975年 | 3212篇 |
1974年 | 3297篇 |
1973年 | 3347篇 |
1972年 | 2987篇 |
1971年 | 2757篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
V. S. -Kh. Kim V. A. Samoilov E. M. Sherysheva Chen Yun 《Chemical and Petroleum Engineering》1993,29(8):355-358
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 8, pp. 9–11, August, 1993. 相似文献
993.
994.
995.
Composite materials of steel sheets joined by interlayers of zinc or lead- tin, show very good impact and corrosion resistance properties. Resistance spot-weld characteristics of these composite materials made of steel sheets and non-ferrous metals have been tested. Spot welds of composites with both zinc and lead- tin interlayers present good behaviour in peeling tests. Shear tests of the welds also show very high strength, probably as a consequence of simultaneous brazing because of the alloyed layer of non-ferrous material around the weld spot. This good welding behaviour enhances the possibilities of application of this composite. 相似文献
996.
V.I. Fabrikant 《International Journal of Engineering Science》1996,34(15):1753-1765
Two mathematically equivalent problems are solved exactly and in terms of elementary functions. An. external circular crack in a transversely isotropic elastic space is interacting with arbitrarily located point forces, applied in such a way, that the tangential displacements in the crack neck vanish. The problem of finding the tangential stress produced by such loading is solved exactly and in closed form. The second problem is that of interaction of an arbitrary point force inside the transversely isotropic elastic half-space and a flexible punch. The method of solution is based on the previously published results of the author. The results are of fundamental value, since they effectively give the Green's functions for solving any relevant problem of interaction. 相似文献
997.
S. V. Shvets 《Strength of Materials》1996,28(3):228-233
A simple method has been devised for determining the length of a deformation wave in a solid. The method is based on the phenomenon of metalcutting and makes use of the interference of coherent waves. A hypothesis regarding the wave propagation of mechanical and thermal energy is proven experimentally, and it is established that the frequency of these oscillations increases with an increase in deformation rate.Translated from Problemy Prochnosti, No. 3, pp. 88–95, March, 1996. 相似文献
998.
A method is proposed for calculating an electric field in a thin piezoelectric wafer taking into account the injection of
electrons from a metal electrode into an insulator. The static current-voltage characteristic of a metal-insulator-metal structure
is given, along with the results of a comparison of calculations and experiment.
Translated from Izmeritel'naya Tekhnika, No. 1, pp. 46–48, January, 1996. 相似文献
999.
Results are presented from a model (numerical) experiment performed to check the efficiency of three groups of direct data-analysis
algorithms to be used in satellite location of ground or ocean sources of radiation. The methodology behind the experiment
is also explained.
Translated from Izmeritel'naya Tekhnika, No. 12, pp. 40–44, December, 1996. 相似文献
1000.
A generalized mathematical model of the interaction between hydrogen and structural defects in metals is analyzed. The temporal dependence of hydrogen permeation flow is examined for three typical cases. The approximations to the general equation for hydrogen permeation flow obtained enable one to determine the interaction from experimental data. The extreme values of permeation flow are analyzed. A method for determining the kinetic parameters of interaction for a given permeation flow is suggested. The conclusion is made that, within the framework of the generalized model, it is possible to establish the mechanism of hydrogen trapping.Dnepropetrovsk Institute of Chemical Engineering, Dnepropetrovsk. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 29, No. 5, pp. 25–29, September–October, 1993. 相似文献