全文获取类型
收费全文 | 8913篇 |
免费 | 893篇 |
国内免费 | 686篇 |
专业分类
化学 | 426篇 |
晶体学 | 3篇 |
力学 | 872篇 |
综合类 | 183篇 |
数学 | 7552篇 |
物理学 | 1456篇 |
出版年
2024年 | 16篇 |
2023年 | 94篇 |
2022年 | 127篇 |
2021年 | 192篇 |
2020年 | 219篇 |
2019年 | 211篇 |
2018年 | 231篇 |
2017年 | 249篇 |
2016年 | 306篇 |
2015年 | 177篇 |
2014年 | 393篇 |
2013年 | 633篇 |
2012年 | 403篇 |
2011年 | 490篇 |
2010年 | 441篇 |
2009年 | 550篇 |
2008年 | 586篇 |
2007年 | 538篇 |
2006年 | 515篇 |
2005年 | 444篇 |
2004年 | 399篇 |
2003年 | 364篇 |
2002年 | 489篇 |
2001年 | 284篇 |
2000年 | 324篇 |
1999年 | 275篇 |
1998年 | 243篇 |
1997年 | 206篇 |
1996年 | 145篇 |
1995年 | 118篇 |
1994年 | 103篇 |
1993年 | 91篇 |
1992年 | 90篇 |
1991年 | 93篇 |
1990年 | 66篇 |
1989年 | 44篇 |
1988年 | 36篇 |
1987年 | 23篇 |
1986年 | 33篇 |
1985年 | 38篇 |
1984年 | 31篇 |
1983年 | 13篇 |
1982年 | 31篇 |
1981年 | 27篇 |
1980年 | 25篇 |
1979年 | 11篇 |
1978年 | 16篇 |
1977年 | 12篇 |
1976年 | 15篇 |
1975年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 62 毫秒
1.
Marcus Carlsson 《Expositiones Mathematicae》2021,39(1):149-157
von Neumann’s inequality in matrix theory refers to the fact that the Frobenius scalar product of two matrices is less than or equal to the scalar product of the respective singular values. Moreover, equality can only happen if the two matrices share a joint set of singular vectors, and this latter part is hard to find in the literature. We extend these facts to the separable Hilbert space setting, and provide a self-contained proof of the “latter part”. 相似文献
2.
3.
Rong Yin Jihui Zhang Xudong Shang 《Mathematical Methods in the Applied Sciences》2020,43(15):8736-8752
This paper is dedicated to studying the following Schrödinger–Poisson system Under some different assumptions on functions V(x), K(x), a(x) and f(u), by using the variational approach, we establish the existence of positive ground state solutions. 相似文献
4.
This paper deals with the Cauchy–Dirichlet problem for the fractional Cahn–Hilliard equation. The main results consist of global (in time) existence of weak solutions, characterization of parabolic smoothing effects (implying under proper condition eventual boundedness of trajectories), and convergence of each solution to a (single) equilibrium. In particular, to prove the convergence result, a variant of the so-called ?ojasiewicz–Simon inequality is provided for the fractional Dirichlet Laplacian and (possibly) non-analytic (but ) nonlinearities. 相似文献
5.
In this paper, we investigate the evolution of joint invariants under invariant geometric flows using the theory of equivariant moving frames and the induced invariant discrete variational complex. For certain arc length preserving planar curve flows invariant under the special Euclidean group , the special linear group , and the semidirect group , we find that the induced evolution of the discrete curvature satisfies the differential‐difference mKdV, KdV, and Burgers' equations, respectively. These three equations are completely integrable, and we show that a recursion operator can be constructed by precomposing the characteristic operator of the curvature by a certain invariant difference operator. Finally, we derive the constraint for the integrability of the discrete curvature evolution to lift to the evolution of the discrete curve itself. 相似文献
6.
In this paper, we consider a viscoelastic wave equation of variable coefficients in the presence of past history with nonlinear damping and delay in the internal feedback and dynamic boundary conditions. Under suitable assumptions, we establish an explicit and general decay rate result without imposing restrictive assumption on the behavior of the relaxation function at infinity by Riemannian geometry method and Lyapunov functional method. 相似文献
7.
M.A. Tawhid 《Journal of Optimization Theory and Applications》2002,113(1):149-164
In this paper, we give some sufficient conditions for the local uniqueness of solutions to nonsmooth variational inequalities where the underlying functions are H-differentiable and the underlying set is a closed convex set/polyhedral set/box/polyhedral cone. We show how the solution of a linearized variational inequality is related to the solution of the variational inequality. These results extend/unify various similar results proved for C
1 and locally Lipschitzian variational inequality problems. When specialized to the nonlinear complementarity problem, our results extend/unify those of C
2 and C
1 nonlinear complementarity problems. 相似文献
8.
Matt Visser Carlos Barceló Stefano Liberati 《General Relativity and Gravitation》2002,34(10):1719-1734
Condensed matter systems, such as acoustics in flowing fluids, light in moving dielectrics, or quasiparticles in a moving superfluid, can be used to mimic aspects of general relativity. More precisely these systems (and others) provide experimentally accessible models of curved-space quantum field theory. As such they mimic kinematic aspects of general relativity, though typically they do not mimic the dynamics. Although these analogue models are thereby limited in their ability to duplicate all the effects of Einstein gravity they nevertheless are extremely important—they provide black hole analogues (some of which have already been seen experimentally) and lead to tests of basic principles of curved-space quantum field theory. Currently these tests are still in the realm of gedanken-experiments, but there are plausible candidate models that should lead to laboratory experiments in the not too distant future. 相似文献
9.
10.
Michel Weber 《Transactions of the American Mathematical Society》2006,358(2):911-936
We apply a majorizing measure theorem of Talagrand to obtain uniform bounds for sums of random variables satisfying increment conditions of the type considered in Gál-Koksma Theorems. We give some applications.