全文获取类型
收费全文 | 7741篇 |
免费 | 232篇 |
专业分类
化学 | 4182篇 |
晶体学 | 45篇 |
力学 | 136篇 |
数学 | 1619篇 |
物理学 | 1991篇 |
出版年
2023年 | 60篇 |
2021年 | 102篇 |
2020年 | 116篇 |
2019年 | 95篇 |
2018年 | 167篇 |
2017年 | 189篇 |
2016年 | 407篇 |
2015年 | 269篇 |
2014年 | 309篇 |
2013年 | 713篇 |
2012年 | 377篇 |
2011年 | 493篇 |
2010年 | 299篇 |
2009年 | 249篇 |
2008年 | 249篇 |
2007年 | 179篇 |
2006年 | 153篇 |
2005年 | 86篇 |
2004年 | 91篇 |
2003年 | 104篇 |
2002年 | 120篇 |
2001年 | 103篇 |
2000年 | 81篇 |
1999年 | 102篇 |
1998年 | 92篇 |
1997年 | 94篇 |
1996年 | 95篇 |
1995年 | 81篇 |
1994年 | 74篇 |
1993年 | 68篇 |
1992年 | 72篇 |
1991年 | 64篇 |
1989年 | 59篇 |
1988年 | 67篇 |
1987年 | 70篇 |
1986年 | 66篇 |
1985年 | 93篇 |
1984年 | 83篇 |
1983年 | 75篇 |
1982年 | 69篇 |
1981年 | 71篇 |
1980年 | 84篇 |
1979年 | 77篇 |
1978年 | 81篇 |
1977年 | 84篇 |
1976年 | 64篇 |
1974年 | 71篇 |
1973年 | 75篇 |
1966年 | 64篇 |
1965年 | 66篇 |
排序方式: 共有7973条查询结果,搜索用时 0 毫秒
1.
We study condensation of ethanol-hexanol vapour by numerical solution of kinetic equations. The number of droplets formed
in unit volume is computed within self-consistent classical model. It is shown that formation of ethanol-rich droplets prevails
at the initial stage of nucleation process, but in the stationary state formation of droplets near the saddle point (on cluster
formation energy surface) plays the dominant role.
Presented at the 6th Joint Seminar “Development of Materials Science in Research and Education”, Karlštejn, Czech Republic,
17–19 September 1996.
This work was supported by Grant No. A1010615 of the Grant Agency of the Academy of Sciences of the Czech Republic. 相似文献
2.
The purpose of this paper is to give the Reid ``Roundabout Theorem' for quadratic functionals with general boundary conditions.
In particular, we describe the so-called coupled point and regularity condition introduced in [16] in terms of Riccati equation
solutions.
Accepted 27 February 1996 相似文献
3.
On‐line coupling of LC and ICP‐MS has been used for fractionation and detection of species of Cu, Fe, I, Se and Zn in human serum. It has been shown that anion exchange chromatography provided better separation capability (both intra‐ and inter‐element) than size‐exclusion chromatography. The mobile phases for ion exchange chromatography consisted of Tris–HNO3 buffer and ammonium salt (nitrate, acetate or formate). Formate was found to be the best mobile phase counter ion, enabling good chromatographic separation, and is acceptable for mass spectrometry too. The quantitative evaluation of element concentrations adhering to individual fractions was performed by the peak area normalization method. The repeatability of results ranged from 3 to 15% (depending on the element concentration level) and represented the main part of the result uncertainty. The accuracy of Cu and Zn fraction determinations was confirmed by comparison with the isotope dilution technique. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献
4.
The complete set of self-consistent parameters of nominally undoped LiNbO3 crystals of congruent composition that describe the electro-optic, piezoelectric, elasto-optic, elastic, and dielectric response
has been determined by numerically evaluating available measurements. The parameters were determined at room temperature and
consist of the low-frequency clamped dielectric constants εS
ij, elastic stiffness constants at constant electric field CE
ijkl, piezoelectric stress coefficients eijk, elasto-optic constants at constant electric field pE
ijkl, and clamped electro-optic coefficients rS
ijk. It is shown that the complete set is required for calculating the effective electro-optic coefficients and dielectric constants
in photorefractive applications of LiNbO3.
Received: 4 January 2002 / Revised version: 1 February 2002 / Published online: 14 March 2002 相似文献
5.
Summary The paper addresses the problem of the implementation of nonhomogeneous essential Dirichlet type boundary conditions in thep-version of the finite element method.Partially supported by the Office of Naval Research under Grant N-00014-85-K-0169Research partially supported by the Air Force Office of Scientific Research, Air Force Systems Command, USAF, under Grant Number AFOSR 85-0322 相似文献
6.
7.
8.
The rate-dependent effects in metallic ferromagnetic materials with magnetization processes attributed to domain-walls motion were studied. The experimental method for eddy-current relaxation time determination was proposed. Some discrepancies between the data and theoretical predictions were observed and discussed. The origin of these discrepancies is accounted for by the decrease of viscous-type relaxation process as the rate of change of averaged magnetization is approaching zero. 相似文献
9.
Július Korbaš 《Acta Mathematica Hungarica》2004,105(1-2):129-137
We prove new results about the vector field problem on the real flag manifolds O(n)/O(1) x O(1) x O(n - 2). For some infinite families of these manifolds, we completely solve the vector field problem. 相似文献
10.
Given disjoint setsP
1,P
2, ...,P
d
inR
d
withn points in total, ahamsandwich cut is a hyperplane that simultaneously bisects theP
i
. We present algorithms for finding ham-sandwich cuts in every dimensiond>1. Whend=2, the algorithm is optimal, having complexityO(n). For dimensiond>2, the bound on the running time is proportional to the worst-case time needed for constructing a level in an arrangement
ofn hyperplanes in dimensiond−1. This, in turn, is related to the number ofk-sets inR
d−1
. With the current estimates, we get complexity close toO(n
3/2
) ford=3, roughlyO(n
8/3
) ford=4, andO(n
d−1−a(d)
) for somea(d)>0 (going to zero asd increases) for largerd. We also give a linear-time algorithm for ham-sandwich cuts inR
3 when the three sets are suitably separated.
A preliminary version of the results of this paper appeared in [16] and [17]. Part of this research by J. Matoušek was done
while he was visiting the School of Mathematics, Georgia Institute of Technology, Atlanta, and part of his work on this paper
was supported by a Humboldt Research Fellowship. W. Steiger expresses gratitude to the NSF DIMACS Center at Rutgers, and his
research was supported in part by NSF Grants CCR-8902522 and CCR-9111491. 相似文献