全文获取类型
收费全文 | 5012篇 |
免费 | 610篇 |
国内免费 | 433篇 |
专业分类
化学 | 942篇 |
晶体学 | 25篇 |
力学 | 1334篇 |
综合类 | 55篇 |
数学 | 1879篇 |
物理学 | 1820篇 |
出版年
2024年 | 6篇 |
2023年 | 64篇 |
2022年 | 82篇 |
2021年 | 104篇 |
2020年 | 132篇 |
2019年 | 114篇 |
2018年 | 123篇 |
2017年 | 146篇 |
2016年 | 178篇 |
2015年 | 173篇 |
2014年 | 233篇 |
2013年 | 431篇 |
2012年 | 245篇 |
2011年 | 343篇 |
2010年 | 240篇 |
2009年 | 269篇 |
2008年 | 277篇 |
2007年 | 305篇 |
2006年 | 304篇 |
2005年 | 262篇 |
2004年 | 245篇 |
2003年 | 216篇 |
2002年 | 201篇 |
2001年 | 177篇 |
2000年 | 192篇 |
1999年 | 145篇 |
1998年 | 122篇 |
1997年 | 103篇 |
1996年 | 96篇 |
1995年 | 77篇 |
1994年 | 62篇 |
1993年 | 44篇 |
1992年 | 44篇 |
1991年 | 55篇 |
1990年 | 25篇 |
1989年 | 28篇 |
1988年 | 21篇 |
1987年 | 22篇 |
1986年 | 19篇 |
1985年 | 13篇 |
1984年 | 21篇 |
1983年 | 9篇 |
1982年 | 17篇 |
1981年 | 13篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 5篇 |
1977年 | 10篇 |
1976年 | 6篇 |
1973年 | 5篇 |
排序方式: 共有6055条查询结果,搜索用时 15 毫秒
1.
2.
3.
Volker Elling. 《Mathematics of Computation》2006,75(256):1721-1733
A particular case of initial data for the two-dimensional Euler equations is studied numerically. The results show that the Godunov method does not always converge to the physical solution, at least not on feasible grids. Moreover, they suggest that entropy solutions (in the weak entropy inequality sense) are not well posed.
4.
Shunlong Luo 《Foundations of Physics》2002,32(11):1757-1772
We formulate an elementary statistical game which captures the essence of some fundamental quantum experiments such as photon polarization and spin measurement. We explore and compare the significance of the principle of maximum Shannon entropy and the principle of minimum Fisher information in solving such a game. The solution based on the principle of minimum Fisher information coincides with the solution based on an invariance principle, and provides an informational explanation of Malus' law for photon polarization. There is no solution based on the principle of maximum Shannon entropy. The result demonstrates the merits of Fisher information, and the demerits of Shannon entropy, in treating some fundamental quantum problems. It also provides a quantitative example in support of a general philosophy: Nature intends to hide Fisher information, while obeying some simple rules. 相似文献
5.
姜德元 《浙江大学学报(理学版)》2003,30(5):499-502
研究了NA序列重对数律收敛速度的一般形式,把Davis和Gut的结果推广到了NA的情形,并使梁汉营等人关于对数律一个结果成为特例;作为推论,得到了关于NA序列重对数律收敛速度的充分条件. 相似文献
6.
F. Prez-Willard C. Sürgers H. Von Lhneysen P. Pfundstein 《Physica E: Low-dimensional Systems and Nanostructures》2004,22(4):872-880
The electronic transport through nanostructured bismuth nanobridges has been investigated at low temperatures (T<2 K) and in magnetic fields B up to 8.5 T. The samples show reproducible resistance fluctuations as a function of B, superimposed on a large magnetoresistance of up to 50%. In addition, time-dependent resistance fluctuations in zero magnetic field demonstrate the presence of bistable scatterers in the constriction region of our samples, which are described by two-level systems. Their dynamics are shown to be sensitive to subtle modifications of the static scatterer configuration in their vicinity, which cannot be detected in the sample magnetofingerprint. 相似文献
7.
通过用毛细管测量纯水表面张力系数实验,得到管内径d与接触角θ的相对误差之间的关系曲线,由此说明实验测得的表面张力系数α和理论公式相比呈现一定的偏差,并简单地讨论了实验的理想状态与实际情况的差别. 相似文献
8.
Rachel L. McSwain Alison R. Markowitz Kenneth R. Shull 《Journal of Polymer Science.Polymer Physics》2004,42(20):3809-3821
To develop a greater understanding of interfacial interactions between a semicrystalline polymer and a glassy polymer, adhesion tests were performed on very thin layers of poly(ethylene oxide) (PEO) sandwiched between two layers of poly(tetramethyl bisphenol A polycarbonate) (TMPC). The tests were designed to provide intimate contact between the surfaces while they were heated above the melting point of the PEO and cooled back to room temperature. A contact mechanics approach, based on the Johnson, Kendall, and Roberts theory, was used to determine values of the energy release rate describing the energetic driving force for crack propagation within the interfacial region. The ability to measure crack propagation at large values of the energy release rate was limited by rupture of the silicone elastomer that was used to provide a sufficiently compliant matrix for the adhesion experiment. By cycling the tensile stress at relatively low loading levels, we were able to measure fatigue crack propagation at values of the energy release rate that did not result in failure of the elastomer. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3809–3821, 2004 相似文献
9.
Becky Lavi Abraham Marmur 《Colloids and surfaces. A, Physicochemical and engineering aspects》2004,250(1-3):409-414
An equation for the kinetics of partial drop spreading is proposed. This equation was empirically derived from experimental data for the spreading kinetics of partially wetting liquids in terms of the wet area versus time. The equation has the form of an exponential power law (EPL), and transforms into the well-known power law for complete wetting, when the equilibrium contact angle approaches zero. The EPL fits very well available experimental data. To lend additional support to the validity of this generalized equation, it will be demonstrated that when it is transformed to present the dynamic contact angle (DCA), it fits very well DCA experimental data for other wetting processes, such as capillary flow and tape coating. 相似文献
10.
A. Bourgeat O. Gipouloux E. Marui‐Paloka 《Mathematical Methods in the Applied Sciences》2004,27(4):381-403
In this paper, we study the global behaviour of an underground waste disposal in order to have an accurate upscaled model suitable for the computations involved in safety assessment processes. We start from a detailed model describing the transport of pollutant leaking from a high number of units. Using the method of homogenization, going to the limit, we obtain first a macroscopic model where the sources are now appearing globally. Then we compute a first‐order matched asymptotic expansion and we give the error estimates for this approximation. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献