全文获取类型
收费全文 | 10002篇 |
免费 | 517篇 |
国内免费 | 223篇 |
专业分类
化学 | 5937篇 |
晶体学 | 89篇 |
力学 | 350篇 |
综合类 | 25篇 |
数学 | 1810篇 |
物理学 | 2531篇 |
出版年
2023年 | 88篇 |
2022年 | 204篇 |
2021年 | 238篇 |
2020年 | 228篇 |
2019年 | 247篇 |
2018年 | 253篇 |
2017年 | 202篇 |
2016年 | 328篇 |
2015年 | 331篇 |
2014年 | 358篇 |
2013年 | 679篇 |
2012年 | 618篇 |
2011年 | 715篇 |
2010年 | 428篇 |
2009年 | 420篇 |
2008年 | 524篇 |
2007年 | 467篇 |
2006年 | 460篇 |
2005年 | 406篇 |
2004年 | 354篇 |
2003年 | 314篇 |
2002年 | 275篇 |
2001年 | 203篇 |
2000年 | 172篇 |
1999年 | 137篇 |
1998年 | 107篇 |
1997年 | 101篇 |
1996年 | 117篇 |
1995年 | 84篇 |
1994年 | 117篇 |
1993年 | 88篇 |
1992年 | 102篇 |
1991年 | 86篇 |
1990年 | 71篇 |
1989年 | 52篇 |
1988年 | 55篇 |
1987年 | 47篇 |
1986年 | 55篇 |
1985年 | 77篇 |
1984年 | 78篇 |
1983年 | 46篇 |
1982年 | 76篇 |
1981年 | 66篇 |
1980年 | 66篇 |
1979年 | 61篇 |
1978年 | 66篇 |
1977年 | 62篇 |
1976年 | 54篇 |
1975年 | 44篇 |
1973年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 453 毫秒
971.
Le Thi Phuong Ngoc Nguyen Anh Triet Nguyen Thanh Long 《Nonlinear Analysis: Theory, Methods & Applications》2010,72(3-4):1865-1885
The paper is devoted to the study of a linear wave equation with a nonlinear boundary condition of viscoelastic type. The existence of a weak solution is proved by using the Faedo–Galerkin method. The uniqueness, regularity and asymptotic expansion of the solution are also discussed. 相似文献
972.
Zhongdi Cen Aimin Xu Anbo Le 《Journal of Computational and Applied Mathematics》2010,234(12):3445-3457
A system of coupled singularly perturbed initial value problems with two small parameters is considered. The leading term of each equation is multiplied by a small positive parameter, but these parameters may have different magnitudes. The solution of the system has boundary layers that overlap and interact. The structure of these layers is analyzed, and this leads to the construction of a piecewise-uniform mesh that is a variant of the usual Shishkin mesh. On this mesh a hybrid finite difference scheme is proved to be almost second-order accurate, uniformly in both small parameters. Numerical results supporting the theory are presented. 相似文献
973.
974.
975.
We compute the angular distribution of lepton pairs at fixed transverse momentum using soft-gluon resummation. Theoretical predictions are compared with the recent NA10 experimental data. We also give predictions in the case ofZ 0 production. 相似文献
976.
We predict a nonvanishing baryon asymmetry of the proton sea at low x. It is expected to be about 7% and nearly x-independent at x < 0.5 × 10-3. The asymmetry arises from the baryon-antibaryon component of the Pomeron, rather than from the valence quarks of the proton, which are wide believed carriers of baryon number. Experimental study of x-distribution of the baryon asymmetry of the proton sea can be performed in ep or γp interactions at HERA, where x ~ 10-5 are reachable, smaller than at any of existing or planned proton colliders. 相似文献
977.
978.
Boris S. Kruglikov 《manuscripta mathematica》2003,111(1):51-69
In this paper we prove that only pseudoholomorphic curves appear as J-invariant submanifolds of generic almost complex manifolds (M,J). We also prove there exist no non-trivial automorphisms or submersions of such manifolds. On the other hand we show that
abundance of 1-jets of PH-submanifolds, automorphisms or submersions implies integrability of the almost complex structure.
Received: 19 April 2002 / Revised version: 10 October 2002
Published online: 14 February 2003 相似文献
979.
Barthelemy Le Gac 《Indagationes Mathematicae》2006,17(2):221-230
Let H be a separable complex Hilbert space, A a von Neumann algebra in ?(H),a faithful, normal state on A. We prove that if a sequence (Xn: n ≥ 1) of uncorrelated operators in A is bundle convergent to some operator X in A and Σ∞n=1n−2 Var(Xn) log2(n + 1) < ∞, then X is proportional to the identity operator on H. We also prove an analogous theorem for certain uncorrelated vectors in the completion L2=L2(A,φ) of A given by the Gelfand-Naimark-Segal representation theorem. Both theorems were motivated by a recent one proved by Etemadi and Lenzhen in the classical commutative setting. 相似文献
980.
The structure of the semiconducting glassy As2Se3Hgx system was investigated in a composition range x = 0.005?0.12. An explanation of the anomalous behaviour of the macroscopic density is proposed, based on the analysis of radial electron density distribution curves. A formula is given which correlates quantitatively the magnitude of coordination spheres with the experimental macroscopic density. 相似文献