全文获取类型
收费全文 | 30659篇 |
免费 | 3997篇 |
国内免费 | 2518篇 |
专业分类
电工技术 | 1630篇 |
综合类 | 4015篇 |
化学工业 | 2938篇 |
金属工艺 | 2762篇 |
机械仪表 | 1625篇 |
建筑科学 | 7128篇 |
矿业工程 | 894篇 |
能源动力 | 671篇 |
轻工业 | 1331篇 |
水利工程 | 1500篇 |
石油天然气 | 907篇 |
武器工业 | 330篇 |
无线电 | 2034篇 |
一般工业技术 | 5641篇 |
冶金工业 | 1260篇 |
原子能技术 | 168篇 |
自动化技术 | 2340篇 |
出版年
2024年 | 162篇 |
2023年 | 473篇 |
2022年 | 793篇 |
2021年 | 1015篇 |
2020年 | 1181篇 |
2019年 | 1135篇 |
2018年 | 1093篇 |
2017年 | 1363篇 |
2016年 | 1377篇 |
2015年 | 1351篇 |
2014年 | 1906篇 |
2013年 | 2151篇 |
2012年 | 2231篇 |
2011年 | 2455篇 |
2010年 | 1722篇 |
2009年 | 1798篇 |
2008年 | 1806篇 |
2007年 | 1915篇 |
2006年 | 1763篇 |
2005年 | 1444篇 |
2004年 | 1189篇 |
2003年 | 993篇 |
2002年 | 833篇 |
2001年 | 790篇 |
2000年 | 669篇 |
1999年 | 607篇 |
1998年 | 497篇 |
1997年 | 429篇 |
1996年 | 331篇 |
1995年 | 315篇 |
1994年 | 252篇 |
1993年 | 215篇 |
1992年 | 218篇 |
1991年 | 144篇 |
1990年 | 103篇 |
1989年 | 123篇 |
1988年 | 64篇 |
1987年 | 62篇 |
1986年 | 27篇 |
1985年 | 38篇 |
1984年 | 19篇 |
1983年 | 22篇 |
1982年 | 19篇 |
1981年 | 15篇 |
1980年 | 28篇 |
1979年 | 23篇 |
1978年 | 3篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
71.
Storozhuk V. N. Romashchenko V. A. Lepikhin P. P. Zhurakhovskii S. V. 《Strength of Materials》2002,34(3):300-304
Large deflections of pulse-loaded elliptic and round plates made of hardenable elastoplastic materials are investigated analytically using an energy-based approach. Formulas that are convenient for engineering design have been derived. 相似文献
72.
The bond strength and slip of epoxy-coated reinforcing bars in concrete have been evaluated by carrying out single pullout and double pullout tests. In extended single pullout tests, slip measurements were made while tensile force was applied to reinforcing bars embedded in concrete. In double pullout tests, 20 cycles of load were applied at levels of steel stress between zero and 0·5 times characteristic steel strength. Strains were measured by electrical resistance strain gauges glued inside the bars. Both epoxy-coated and uncoated bars were used in the investigation, to obtain comparative results. The strain gradient along the bar was found to be less for the coated reinforcement. In general, the epoxy coating was found to increase slip in bond and thereby reduce the bond performance of coated bars. 相似文献
73.
彩色PDP用玻璃基板 总被引:4,自引:0,他引:4
本文讨论了彩色PDP现用钠钙玻璃的热稳定性,指出由于这种玻璃在热处理过程中易变形和收缩,因而不适合作大面积彩色PDP基板材料,介绍了彩色PDP基板玻璃的制造方法和特点。最后介绍了日本旭硝子公司和美国康宁公司各自为彩色PDP新开发的玻璃基板材料PD200和CS25。 相似文献
74.
Motoharu Fujigaki In Hong Yang Yoshiharu Morimoto Eung Kyo Han 《NDT & E International》1996,29(4):197-203
There is no good method to measure the shape and the strain distributions of a structure changing with time. We have previously proposed the Fourier transform grid method (FTGM) to measure the three-dimensional shape and surface strain distributions of stationary objects by analysing the two-dimensional grating images recorded with two cameras. In the stereoscopic method, it is very important to determine the accurate geometric parameters of the camera system. In this paper, the positions and the directions of cameras are accurately determined using the FTGM applied to images of a reference object on which a two-dimensional grating is drawn. Applications for analysing shape and strain distributions of vibrating rubber plates and a moving human skin are shown. 相似文献
75.
76.
Results of metal testing in impact tension–compression and indentation are analyzed. As the analysis of these data demonstrates, the strength of metals increases greatly with strain rates and at moderate indentation rates. At high indentation rates, a decrease in the specific energy (per unit volume of a displaced material) necessary for the formation of a conical cavity was observed. The account of the effects of viscosity, temperature increase upon plastic deformation and its localization can be used to explain the above phenomena. 相似文献
77.
P. I. Stetsyuk 《Cybernetics and Systems Analysis》2006,42(1):54-64
New quadratic models are proposed to improve the upper-bound estimates in the maximum weighted cut problem. They are found
by two original methods for deriving redundant quadratic constraints. A well-known linear model is shown to follow from the
models proposed. Recommendations on how to develop its strengthened analogs are given.
This study is partially sponsored from the grant UM2-2574-KV-03 (CRDF Cooperative Grants Program).
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 1, pp. 63—75, January–February 2006. 相似文献
78.
R. P. Okatov F. K. Nizametdinov B. N. Tsai T. T. Bondarenko 《Journal of Mining Science》2003,39(2):139-142
Using the synthesis of the kinetic concept on solid strength and the Coulomb - Mohr strength theory as the base, the failure conditions taking into account the time and temperature factors are obtained. 相似文献
79.
制作了2种形式的铟凸点:即直接蒸发沉积的铟柱和将铟柱回流得到的铟球。同时对比了铟柱和铟球2种凸点的剪切强度,测试结果表明铟球剪切强度为5.6MPa,铟柱的剪切强度为1.9MPa,前者约为后者的2.9倍。对铟凸点微观结构的X光衍射分析发现:铟柱剪切强度低是织构弱化所致;铟球剪切强度高是由于回流破坏了铟柱的理想(101)丝织构模式,从而提高了铟球的剪切强度。 相似文献
80.
The relation between the initial unbalance and the output signal of bridge circuits when acted upon simultaneously by the
physical factor being measured and the temperature of the surroundings when the bridge is supplied from a voltage or current
source is investigated. Analytic relations are obtained which explain the temperature dependence of the useful output voltage
under external physical action.
__________
Translated from Izmeritel’naya Tekhnika, No. 1, pp. 48–49, 2007. 相似文献