全文获取类型
收费全文 | 154880篇 |
免费 | 14413篇 |
国内免费 | 13961篇 |
专业分类
电工技术 | 13216篇 |
技术理论 | 1篇 |
综合类 | 17524篇 |
化学工业 | 17011篇 |
金属工艺 | 13365篇 |
机械仪表 | 9673篇 |
建筑科学 | 9621篇 |
矿业工程 | 5661篇 |
能源动力 | 3866篇 |
轻工业 | 16150篇 |
水利工程 | 4819篇 |
石油天然气 | 7873篇 |
武器工业 | 2301篇 |
无线电 | 14545篇 |
一般工业技术 | 11506篇 |
冶金工业 | 13086篇 |
原子能技术 | 3540篇 |
自动化技术 | 19496篇 |
出版年
2024年 | 815篇 |
2023年 | 2077篇 |
2022年 | 4748篇 |
2021年 | 6046篇 |
2020年 | 4278篇 |
2019年 | 2988篇 |
2018年 | 3211篇 |
2017年 | 3759篇 |
2016年 | 3311篇 |
2015年 | 5285篇 |
2014年 | 6791篇 |
2013年 | 7802篇 |
2012年 | 10042篇 |
2011年 | 13806篇 |
2010年 | 11422篇 |
2009年 | 9822篇 |
2008年 | 10007篇 |
2007年 | 9611篇 |
2006年 | 8512篇 |
2005年 | 7128篇 |
2004年 | 8744篇 |
2003年 | 5489篇 |
2002年 | 5280篇 |
2001年 | 4148篇 |
2000年 | 3094篇 |
1999年 | 2927篇 |
1998年 | 4168篇 |
1997年 | 2983篇 |
1996年 | 1786篇 |
1995年 | 1265篇 |
1994年 | 1068篇 |
1993年 | 2671篇 |
1992年 | 1804篇 |
1991年 | 1284篇 |
1990年 | 1246篇 |
1989年 | 962篇 |
1988年 | 610篇 |
1987年 | 398篇 |
1986年 | 294篇 |
1985年 | 174篇 |
1984年 | 89篇 |
1983年 | 73篇 |
1982年 | 85篇 |
1981年 | 83篇 |
1980年 | 150篇 |
1979年 | 83篇 |
1977年 | 176篇 |
1976年 | 285篇 |
1965年 | 60篇 |
1959年 | 69篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
PENG HongJian WU Qing LI XiaoBo &XIE YouQing School of Chemistry Chemical Engineering Central South University Changsha China School of Material Science Engineering 《中国科学:信息科学(英文版)》2011,(9)
In this paper,taking Nb-Mo alloy system as an example,the equations of concentration of characteristic atoms of alloys in BCC structure were obtained on the basis of the idea of systematic science of alloys and the number of coordination atoms.The concentrations of characteristic atoms in B2-NbMo type ordered alloys were calculated as functions of ordering degree(s) and composition xMo.When s=smax,the concentrations of characteristic atoms of stoichiometric B2-NbMo intermetallic compound are equal to that o... 相似文献
102.
ZHANG YuJun ZHANG WeiQing & YANG ChaoShuai State Key Laboratory of Geomechanics Geotechnical Engineering 《中国科学:信息科学(英文版)》2011,(7)
With the models of stress corrosion and pressure solution, by Yasuhara et al., two computation conditions were designed for a hypothetical nuclear waste repository in an unsaturated dual-porosity rock mass: (i) the fracture apertures are changed with the stress corrosion and pressure solution (the porosity of rock matrix is also a function of stress); (ii) the fracture apertures and the porosity of rock matrix are constants. Then the corresponding two-dimensional FEM analyses for the coupled thermohydro-mec... 相似文献
103.
YAO Yu & ZHANG JingZhou College of Energy Power Engineering Nanjing University of Aeronautics Astronautics Nanjing China 《中国科学:信息科学(英文版)》2011,(7)
Experimental and numerical researches were conducted to investigate the cooling performance of a single row of consoles (converging slot-hole) on a large-scale flat-plate model. The results show that the coolant flow from a row of consoles shows good lateral uniformity of adiabatic effectiveness, with regions of slightly enhanced cooling occurring between the consoles. For the console cooling geometry, the interaction between coolant jet from inclined console and the mainstream flow results in reasonable vo... 相似文献
104.
DALLY B B 《中国科学:信息科学(英文版)》2011,(2)
Moderate or intense low oxygen dilution(MILD)combustion plays a significant role in the mitigation of combustion-generated pollutants and greenhouse gases whilst meeting thermal efficiency needs.However,due to the lack of the fundamental knowledge on this combustion,there is a misconception that MILD combustion should be established by high preheating of the air,which has limited its application.Our research and development on this combustion has been performed for several years. We have found that the requ... 相似文献
105.
LEI Peng CHANG XiaoLin XIAO Feng ZHANG GuiJin & SU HuaiZhi School of Hydraulic Engineering Changsha University of Science Technology Changsha China College of Water Resources Hydroelectric Engineering Wuhan University.Wuhan Mid-south Design Research Institute China Hydropower Engineering Consulting Group Co Changsha College of Water Conservancy Hydropower Engineering Hohai University Nanjing 《中国科学:信息科学(英文版)》2011,(6)
Owing to the deficiency in early warning for high concrete dam,a formula was established to characterize the deformation behavior of high concrete dam as a whole.The early warning index of spatial deformation was calculated by low probability principle on the basis of the deformation entropy formula proposed.The steps were as follows.Firstly,the probability method was utilized to define the degree of order and degree of chaos for each survey point.Secondly,the weight distribution among the survey points was... 相似文献
106.
LIU JunFeng & FENG YuJie State Key Laboratory of Urban Water Resource Environment Harbin Institute of Technology Harbin China 《中国科学E辑(英文版)》2009,(6)
SnO2 electrodes have many advantages in the degradation of toxic or bio-refractory organic wastewater,and SnO2 is a kind of anode material which has the potential to be widely used.Electrocatalytic effi-ciency and service life of Ti\SnO2 electrodes are key factors that can influence its applications.In order to enhance the electrocatalytic characteristics of Ti\SnO2 electrodes,a type of electrocatalytic electrode with nanocoating was prepared by direct current(DC)electrodeposition method and thermal oxidati... 相似文献
107.
108.
109.
前文报道了外加磁场对吸附在硅胶表面上的芳砜光解反应的影响,本文报道外加磁场影响光化学反应的另一个例子——电子转移光敏化1,2-二苯乙烯的异构化。 近年来电子转移光敏化反应引起了有机光化学家们的极大注意。一些异构化、重排、裂解、氧化反应都可以通过电子转移机理敏化。电子转移光敏化的机理可以用(1)描述。图中A和D分别代表电子的受体和给体。 相似文献
110.
针对蜂窝与终端直通(Device-to-device,D2D)混合网络中的不完全信道状态信息(Channel state information,CSI),提出了一种基于不完全CSI的最优功率分配算法。利用拉格朗日乘数法推导出了最优功率分配解的闭式表达式。相对于传统的最大发送功率分配方案,该最优解受信道信息误差的影响较小,具有较好的鲁棒性。仿真结果表明,本文算法可以节约发送功率,并得到更大的接收信噪比。 相似文献