全文获取类型
收费全文 | 24851篇 |
免费 | 3955篇 |
国内免费 | 2806篇 |
专业分类
化学 | 17510篇 |
晶体学 | 215篇 |
力学 | 1471篇 |
综合类 | 251篇 |
数学 | 2952篇 |
物理学 | 9213篇 |
出版年
2024年 | 9篇 |
2023年 | 513篇 |
2022年 | 492篇 |
2021年 | 657篇 |
2020年 | 1032篇 |
2019年 | 974篇 |
2018年 | 771篇 |
2017年 | 769篇 |
2016年 | 1099篇 |
2015年 | 1003篇 |
2014年 | 1291篇 |
2013年 | 1735篇 |
2012年 | 2153篇 |
2011年 | 2207篇 |
2010年 | 1505篇 |
2009年 | 1460篇 |
2008年 | 1660篇 |
2007年 | 1505篇 |
2006年 | 1433篇 |
2005年 | 1180篇 |
2004年 | 957篇 |
2003年 | 847篇 |
2002年 | 742篇 |
2001年 | 620篇 |
2000年 | 549篇 |
1999年 | 604篇 |
1998年 | 475篇 |
1997年 | 424篇 |
1996年 | 436篇 |
1995年 | 404篇 |
1994年 | 361篇 |
1993年 | 336篇 |
1992年 | 296篇 |
1991年 | 245篇 |
1990年 | 232篇 |
1989年 | 169篇 |
1988年 | 126篇 |
1987年 | 68篇 |
1986年 | 85篇 |
1985年 | 61篇 |
1984年 | 25篇 |
1983年 | 33篇 |
1982年 | 34篇 |
1981年 | 17篇 |
1980年 | 7篇 |
1979年 | 5篇 |
1976年 | 1篇 |
1957年 | 5篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
The authors consider the short time existence for Ricci-Bourguignon flow on manifolds with boundary. If the initial metric has constant mean curvature and satisfies some compatibility conditions, they show the short time existence of the Ricci-Bourguignon flow with constant mean curvature on the boundary. 相似文献
2.
A type of infinite horizon forward-backward doubly stochastic differential equations is studied.Under some monotonicity assumptions,the existence and uniqueness results for measurable solutions are established by means of homotopy method.A probabilistic interpretation for solutions to a class of stochastic partial differential equations combined with algebra equations is given.A significant feature of this result is that the forward component of the FBDSDEs is coupled with the backward variable. 相似文献
3.
Wang Muhan Lin Haifeng Mu Ruizhen Zhu Wenzhang Xiong Feibing 《Journal of Russian Laser Research》2021,42(4):494-500
Journal of Russian Laser Research - We report a single- and triple-wavelength Nd:GGG laser operating in the 1.3 μm wavelength range with 880 nm laser diode pumping directly into the 4F3/2... 相似文献
4.
Zhang Lei Xu Chao Guo Yaohao Zhu Guangpu Cai Shiyu Wang Xin Jing Wenlong Sun Hai Yang Yongfei Yao Jun 《Transport in Porous Media》2021,140(3):713-725
Transport in Porous Media - Pore scale immiscible displacement is crucial in oil industry. The surface roughness of throat is an important factor affecting water–oil interface movement. In... 相似文献
5.
Mechanics of Composite Materials - Aiming at the phenomenon of delamination and serious tool wear when processing carbon-carbon composite materials by traditional mechanical tools, an abrasive... 相似文献
6.
Ma Xiyuan Wang Chaonan Li Zexi Zhu Hongfeng 《International Journal of Theoretical Physics》2021,60(4):1328-1338
International Journal of Theoretical Physics - Security, efficiency and universality are the major concerns in distributed computation for how to communicate securely as there are a large number of... 相似文献
7.
Jackson Crane Xian Shi Jonathan T. Lipkowicz Andreas M. Kempf Hai Wang 《Proceedings of the Combustion Institute》2021,38(3):3585-3593
A geometric model with a low computational complexity capable of simulating detonation behavior in physical systems is proposed. In support of the geometric model development, a series of cylindrical 1D simulations with a variable size initiation kernel are performed in hydrogen-oxygen mixtures. From these 1D simulations a detonation cell stabilization mechanism is identified. The stabilization mechanism is predicated on the size of the gap between the pressure and temperature fronts at the point where the average pressure front velocity along one cell length is equal to the CJ velocity. This gap, in a multidimensional detonation, is the ignition kernel of a subsequent blast, and dictates the formation of the subsequent cell. Serial analysis of blasts in this context leads to a unique stable blast kernel size for any mixture, which, within the uncertainty of the initial kernel state, can predict the experimental cell length for mixtures considered in this study. Using a tabulation of the 1D simulations as an input, a formulation and sample results of the geometric model are shown. The geometric model can reproduce both qualitative and quantitative features of experimental detonation cellular structure. 相似文献
8.
Acta Mathematicae Applicatae Sinica, English Series - So far there have been few results presented on the exponential stability for time-changed stochastic differential equations. The main aim of... 相似文献
9.
Liu Zhu Sun Wen-Yang Fan Xiao-Gang Wang Dong Ye Liu 《International Journal of Theoretical Physics》2021,60(7):2412-2422
International Journal of Theoretical Physics - In this paper, we investigate Einstein-Podolsky-Rosen steering, Bell non-locality, first-order coherence and concurrence in the spin- $\frac {1}{2}$... 相似文献
10.
本文基于CO2溶于水形成碳酸的原理,提出生物质电厂烟气强化水洗法,对生物质中水不溶AAEM(如有机AAEM、CaCO3及CaSO4等)进行有效脱除,从而抑制其燃烧过程的结渣沾污.实验结果表明,烟气强化水洗对生物质中Na、P、S、Cl、K、Ca等无机元素均有很好的脱除效果,且明显优于传统水洗,K和Ca的脱除率分别达到87%和40%.烟气强化水洗明显抑制了生物质燃烧过程中灰的熔融结渣现象,灰的软化温度从原料灰的982℃提高到了1034℃.所以,烟气强化水洗是一种有效的抑制生物质燃烧过程中结渣沾污的方法.而且,此方法也提出了一条生物质电厂烟气资源化利用的新途径. 相似文献