全文获取类型
收费全文 | 404篇 |
免费 | 14篇 |
国内免费 | 3篇 |
专业分类
化学 | 146篇 |
力学 | 11篇 |
数学 | 151篇 |
物理学 | 113篇 |
出版年
2023年 | 3篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 3篇 |
2016年 | 14篇 |
2015年 | 16篇 |
2014年 | 13篇 |
2013年 | 23篇 |
2012年 | 17篇 |
2011年 | 12篇 |
2010年 | 15篇 |
2009年 | 23篇 |
2008年 | 21篇 |
2007年 | 27篇 |
2006年 | 19篇 |
2005年 | 17篇 |
2004年 | 12篇 |
2003年 | 14篇 |
2002年 | 12篇 |
2001年 | 6篇 |
2000年 | 10篇 |
1999年 | 4篇 |
1998年 | 6篇 |
1997年 | 8篇 |
1996年 | 10篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 8篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 6篇 |
1985年 | 2篇 |
1983年 | 4篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 2篇 |
1979年 | 3篇 |
1978年 | 6篇 |
1977年 | 4篇 |
1976年 | 3篇 |
1975年 | 6篇 |
1974年 | 4篇 |
1968年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有421条查询结果,搜索用时 0 毫秒
21.
22.
A rare case of thermodynamic miscibility has been demonstrated in the amorphous state (quenched glass as well as molten state) of a ternary blend system formed by poly(ether imide) and semicrystalline poly(ethylene terephthalate) and poly-(butylene terephthalate). A single glass transition temperature (Tg) in the ternary blends was observed using differential scanning calorimetry and dynamic mechanical analysis. 相似文献
23.
Felix Finster Joel Smoller Shing-Tung Yau 《Communications in Mathematical Physics》1999,205(2):249-262
We consider for j=?, … a spherically symmetric, static system of (2j+1) Dirac particles, each having total angular momentum j. The Dirac particles interact via a classical gravitational and electromagnetic field.
The Einstein–Dirac–Maxwell equations for this system are derived. It is shown that, under weak regularity conditions on the
form of the horizon, the only black hole solutions of the EDM equations are the Reissner–Nordstr?m solutions. In other words,
the spinors must vanish identically. Applied to the gravitational collapse of a “cloud” of spin-?-particles to a black hole,
our result indicates that the Dirac particles must eventually disappear inside the event horizon.
Received: 2 November 1998 / Accepted: 23 February 1999 相似文献
24.
On the curvature of compact Hermitian manifolds 总被引:3,自引:0,他引:3
Shing-Tung Yau 《Inventiones Mathematicae》1974,25(3-4):213-239
25.
We consider random d‐regular graphs on N vertices, with degree d at least (log N)4. We prove that the Green's function of the adjacency matrix and the Stieltjes transform of its empirical spectral measure are well approximated by Wigner's semicircle law, down to the optimal scale given by the typical eigenvalue spacing (up to a logarithmic correction). Aside from well‐known consequences for the local eigenvalue distribution, this result implies the complete (isotropic) delocalization of all eigenvectors and a probabilistic version of quantum unique ergodicity.© 2017 Wiley Periodicals, Inc. 相似文献
26.
Inspired by Durfee Conjecture in singularity theory, Yau formulated the Yau number theoretic conjecture(see Conjecture 1.3) which gives a sharp polynomial upper bound of the number of positive integral points in an n-dimensional(n≥3) polyhedron. It is well known that getting the estimate of integral points in the polyhedron is equivalent to getting the estimate of the de Bruijn function ψ(x, y), which is important and has a number of applications to analytic number theory and cryptography. We prove the Yau number theoretic conjecture for n = 6. As an application, we give a sharper estimate of function ψ(x, y) for 5≤y 17, compared with the result obtained by Ennola. 相似文献
27.
In relativity, the energy of a moving particle depends on the observer, and the rest mass is the minimal energy seen among all observers. The Wang–Yau quasi-local mass for a surface in spacetime introduced in Wang and Yau (Phys Rev Lett 102(2):021101, 2009 ; Commun Math Phys 288(3):919–942, 2009) is defined by minimizing quasi-local energy associated with admissible isometric embeddings of the surface into the Minkowski space. A critical point of the quasi-local energy is an isometric embedding satisfying the Euler–Lagrange equation. In this article, we prove results regarding both local and global minimizing properties of critical points of the Wang–Yau quasi-local energy. In particular, under a condition on the mean curvature vector we show a critical point minimizes the quasi-local energy locally. The same condition also implies that the critical point is globally minimizing among all axially symmetric embedding provided the image of the associated isometric embedding lies in a totally geodesic Euclidean 3-space. 相似文献
28.
Abstract This article presents the empirical study of a heat pipe heat exchanger that was directly experiencing the ambient tropical air in its evaporator section. The performance of the heat pipe heat exchanger was monitored during two weeks of operation to determine the performance curves. The temperature of return air was controlled at about 22°C as the representative temperature of inside air, and a face velocity of 2 m/s on the heat pipe heat exchanger coil was established for this purpose. It was found that for the present investigation, the heat pipe heat exchanger can pay for itself in 1.5 years. 相似文献
29.
Bruno?NachtergaeleEmail author Horng-Tzer?Yau 《Communications in Mathematical Physics》2003,243(3):485-540
We derive the Euler equations from quantum dynamics for a class of fermionic many-body systems. We make two types of assumptions. The first type are physical assumptions on the solution of the Euler equations for the given initial data. The second type are a number of reasonable conjectures on the statistical mechanics and dynamics of the Fermion Hamiltonian.©2003 B. Nachtergaele and H.-T. Yau. This article may be reproduced in its entirety for non-commercial purposes.Research partially supported by NSF # DMS-0070774.Research partially supported by NSF # DMS-0072098, the Veblen Fund from the Institute for Advanced Study and a Fellowship from the MacArthur Foundation. 相似文献
30.
Tang L.C. Chang C.C. Chen T.C. Yau H.F. Ye P.X. 《Optical and Quantum Electronics》2002,34(12):1241-1249
We propose a novel geometry for a self-pumped phase conjugator that uses a +c-face incident configuration in a photorefractive pentagon-shaped 0°-cut BaTiO3 crystal for obtaining fast response in phase conjugation. A steady phase-conjugate output with a fast response time 0.4 s is obtained when the incident beam has a 4 W/cm2 intensity. The influences of position and angle on the temporal phase-conjugate response are also investigated. The advantage of this phase conjugator using this novel configuration is improved resolution of a phase-distorted image with a value as high as 128 lp/mm. 相似文献