全文获取类型
收费全文 | 87629篇 |
免费 | 7355篇 |
国内免费 | 5504篇 |
专业分类
化学 | 24250篇 |
晶体学 | 1848篇 |
力学 | 7309篇 |
综合类 | 425篇 |
数学 | 21939篇 |
物理学 | 44717篇 |
出版年
2023年 | 236篇 |
2022年 | 351篇 |
2021年 | 470篇 |
2020年 | 848篇 |
2019年 | 1125篇 |
2018年 | 1106篇 |
2017年 | 841篇 |
2016年 | 722篇 |
2015年 | 600篇 |
2014年 | 1377篇 |
2013年 | 2237篇 |
2012年 | 1528篇 |
2011年 | 2135篇 |
2010年 | 2678篇 |
2009年 | 7244篇 |
2008年 | 8265篇 |
2007年 | 6777篇 |
2006年 | 6226篇 |
2005年 | 4401篇 |
2004年 | 4136篇 |
2003年 | 4342篇 |
2002年 | 5536篇 |
2001年 | 4046篇 |
2000年 | 3791篇 |
1999年 | 3599篇 |
1998年 | 3020篇 |
1997年 | 2119篇 |
1996年 | 1898篇 |
1995年 | 2324篇 |
1994年 | 2243篇 |
1993年 | 1671篇 |
1992年 | 1205篇 |
1991年 | 911篇 |
1990年 | 737篇 |
1989年 | 637篇 |
1988年 | 590篇 |
1987年 | 432篇 |
1985年 | 974篇 |
1984年 | 638篇 |
1983年 | 512篇 |
1982年 | 650篇 |
1981年 | 799篇 |
1980年 | 725篇 |
1979年 | 563篇 |
1978年 | 583篇 |
1977年 | 542篇 |
1976年 | 541篇 |
1975年 | 319篇 |
1974年 | 355篇 |
1973年 | 464篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
何先应 《南昌大学学报(理科版)》2004,28(4):338-340
设G是有限群。H是G的一个正规子群。P是|H|的一个素因子。P是H的一个Sylow p-子群。若下列条件之一满足。则H是p-幂零:1)P的极大子群都是G的CAP-子群且(|H|,P-1)=1;2)P的二次极大子群都是G的CAP-子群且(|H|,P^2-1)=1。特别地,若进一步假设G/H为P-幂零且(|G|,P-1)=1或(|G|,P^2-1)=1。则G自身亦为P-幂零。 相似文献
192.
摘要:本文在L_[0.1]~p空间给出了 Durrmeyer型修正的shepard算子D_n(f,x),对 f∈L_[0.1]~p,(p≥1),得到了下列的Jackson型估计:││D)n(f)-f││_p≤ C_(pλω)(f,n~(-1))p,λ≥2, Cω(f,n~(-1)logn)p,λ=2, C_(pλω)(f,n~(-1))p,1<λ<2, 相似文献
193.
We derive the Friedmann-like equations in braneworld cosmology by imposing the first law of thermodynamics and Bekenstein's area-entropy formula on the apparent horizon of a Friedmann–Robertson–Walker universe in both Randall–Sundrum II gravity and Dvali–Gabadadze–Porrati gravity models. Israel's boundary condition plays an important role in our calculations in both cases, besides the first law of thermodynamics and Bekenstein's area-entropy formula. The results indicate that thermodynamics on the brane world knows the behaviors of gravity. 相似文献
194.
Band bending at the Ni/Si(100)-2×1 interface has been monitored by using Si 2p core level photoemission spectra. Two nickel-induced Si 2p components appear in the initial interaction between Ni and Si(100)-2×1, which is confined at the top surface and the first subsurface layers. At Ni coverage less than 0.0375 ML, Ni atoms prefer the adamantane interstitial sites on the first subsurface, but switch to the pedestal sites on Si dimer rows at higher Ni coverage. The change in the preferred occupation sites of Ni atoms on the Si(100)-2×1 surface strongly affects the amount of band bending shift. The shift towards higher binding energy, when Ni atoms occupy the adamantane interstitial sites, is attributed to metal-induced-gap states. While Ni atoms occupy the pedestal sites, the band bending shift is reduced which is attributed to the passivation of surface states. 相似文献
195.
Abstract. We propose a general approach to deal with nonlinear, nonconvex variational problems based on a reformulation of the problem
resulting in an optimization problem with linear cost functional and convex constraints. As a first step we explicitly explore
these ideas to some one-dimensional variational problems and obtain specific conclusions of an analytical and numerical nature. 相似文献
196.
曾六川 《高等学校计算数学学报(英文版)》2003,12(1)
The purpose of this paper is to investigate the problem of approximating fixed points of non-Lipschitizian asymptotically pseudocontractive mappings in an arbitrary real Banach space by the modified Ishikawa iterative sequences with errors. 相似文献
197.
H.L. Xu A. Persson S. Svanberg 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,23(2):233-236
New radiative lifetime measurements based on time-resolved laser-induced fluorescence techniques are reported for 18 even-parity
levels belonging to the 4f5d26p and 4f
25d
2 configurations of Ce I and 6 even-parity levels belonging to the 5d26s, 4f5d6p, and 4f6s6p configurations of Ce II. Free neutral and singly ionized cerium atoms were produced by laser ablation. The Ce I and Ce II
levels range in energy from 26 545 to 29 102 cm-1, and 42 573 to 48 152 cm-1, respectively.
Received 25 September 2002 Published online 4 March 2003 相似文献
198.
Roland Glowinski Jiwen He Jacques Rappaz Joël Wagner 《Comptes Rendus Mathematique》2003,337(10):679-684
In this paper we present a method to solve numerically elliptic problems with multi-scale data using multiple levels of not necessarily nested grids. The method consists in calculating successive corrections to the solution in patches whose discretizations are not necessarily conforming. It resembles the FAC method (see Math. Comp. 46 (174) (1986) 439–456) and its convergence is obtained by a domain decomposition technique (see Math. Comp. 57 (195) (1991) 1–21). However it is of much more flexible use in comparison to the latter. To cite this article: R. Glowinski et al., C. R. Acad. Sci. Paris, Ser. I 337 (2003). 相似文献
199.
Miklós Csörgő 《Periodica Mathematica Hungarica》2005,50(1-2):1-27
Summary This article provides a glimpse of some of the highlights of the joint work of Endre Csáki and Pál Révész since 1979. The topics of this short exploration of the rich stochastic milieu of this inspiring collaboration revolve around Brownian motion, random walks and their long excursions, local times and additive functionals, iterated processes, almost sure local and global central limit theorems, integral functionals of geometric stochastic processes, favourite sites--favourite values and jump sizes for random walk and Brownian motion, random walking in a random scenery, and large void zones and occupation times for coalescing random walks. 相似文献
200.
Alessandro Conflitti 《Finite Fields and Their Applications》2003,9(4):423-431
We propose a probabilistic algorithm to reduce computing the greatest common divisor of m polynomials over a finite field (which requires computing m−1 pairwise greatest common divisors) to computing the greatest common divisor of two polynomials over the same field. 相似文献