全文获取类型
收费全文 | 26293篇 |
免费 | 556篇 |
国内免费 | 285篇 |
专业分类
化学 | 7633篇 |
晶体学 | 258篇 |
力学 | 1944篇 |
综合类 | 465篇 |
数学 | 8277篇 |
物理学 | 8557篇 |
出版年
2023年 | 40篇 |
2022年 | 78篇 |
2021年 | 107篇 |
2020年 | 96篇 |
2019年 | 16篇 |
2018年 | 1968篇 |
2017年 | 2313篇 |
2016年 | 987篇 |
2015年 | 651篇 |
2014年 | 515篇 |
2013年 | 717篇 |
2012年 | 1796篇 |
2011年 | 1079篇 |
2010年 | 48篇 |
2009年 | 154篇 |
2008年 | 109篇 |
2007年 | 104篇 |
2006年 | 113篇 |
2005年 | 5818篇 |
2004年 | 5644篇 |
2003年 | 3132篇 |
2002年 | 266篇 |
2001年 | 58篇 |
2000年 | 51篇 |
1999年 | 132篇 |
1998年 | 110篇 |
1997年 | 45篇 |
1996年 | 14篇 |
1995年 | 12篇 |
1994年 | 44篇 |
1993年 | 161篇 |
1992年 | 166篇 |
1991年 | 99篇 |
1990年 | 74篇 |
1989年 | 78篇 |
1988年 | 69篇 |
1987年 | 9篇 |
1986年 | 40篇 |
1984年 | 5篇 |
1972年 | 45篇 |
1971年 | 18篇 |
1970年 | 19篇 |
1969年 | 22篇 |
1968年 | 21篇 |
1967年 | 13篇 |
1966年 | 9篇 |
1965年 | 6篇 |
1963年 | 8篇 |
1961年 | 9篇 |
1959年 | 6篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
In this paper we construct an example of a word metric on an infinite cyclic subgroup. This example shows that subexponential
distortion does not obstruct non-trivial growth of connected radii. This answers a question of Gromov [6]. The constructed
metric has other pathological properies. Specifically, its asymptotic cone depends on the choice of ultrafilter and scaling
sequence.
The work has been partially supported by the Swiss National Science Foundation. 相似文献
2.
d 《European Journal of Combinatorics》2002,23(8):1079
Assume that d ≥ 4. Then there exists a d -dimensional dual hyperoval in PG(d + n, 2) for d + 1 ≤ n ≤ 3 d − 7. 相似文献
3.
4.
5.
6.
本文用凸函数的方法研究了概率测度的矩母函数和由C.J.Stone提出的拟对称性,并刻画了Martin边界的法向量.拟对称性在随机游动的比例极限定理中是一个重要的概念.这些结果可应用于Levy过程的研究. 相似文献
7.
We study a class of shape optimization problems for semi-linear elliptic equations with Dirichlet boundary conditions in smooth
domains in ℝ2. A part of the boundary of the domain is variable as the graph of a smooth function. The problem is equivalently reformulated
on a fixed domain. Continuity of the solution to the state equation with respect to domain variations is shown. This is used
to obtain differentiability in the general case, and moreover a useful formula for the gradient of the cost functional in
the case where the principal part of the differential operator is the Laplacian.
Online publication 23 January 2004. 相似文献
8.
9.
J. Kircher M. Cardona M. Alouani S. Gopalan O. Jepsen O. K. Andersen
E. Kaldis
J. Karpinski S. Rusieki 《Physica C: Superconductivity and its Applications》1992,200(3-4):413-417We report results of ellipsometric measurements of the dielectric tensor of YBa2Cu4O8 as well as calculations employing density functional theory in the local density approximation (LDA). For the computation of the one-electron eigenvalues and states the linear-muffin-tin-orbital method (LMTO) was used. Measured and calculated results show good agreement. In particular, the calculation predicts different band structures for YBa2Cu3O7 and YBa2Cu4O8 in the vicinity of the Fermi energy which lead to significant differences in the optical spectra. One such difference is a region of small ε2 in the near infrared which is a fingerprint of the high (relative to the top of the highest fully occupied band) Fermi energy as compared to the situation in YBa2Cu3O7. Our experimental results confirm the theoretical findings. 相似文献
10.
Auguet C. Martorell F. Moll F. Torra V: 《Journal of Thermal Analysis and Calorimetry》2002,70(1):277-290
The miniaturized calorimetric devices furnish a reduced working flat surface and permits measurements with extremely low-mass
quantities. The experimental sensitivity shows relevant position dependence with x-y surface coordinates and with z-distance. The device identification is realized via a 2-D model based in Fourier general equation.
Using the Marquardt method the experimental flat surface device can be identified and the fitted parameters used to simulate
the behavior of the experimental system. From the model, the effects of several dissipation configurations can be evaluated.
Also, via the RC-analogy, a way to 3-D experimental devices is roughly described.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献