全文获取类型
收费全文 | 14802篇 |
免费 | 1465篇 |
国内免费 | 1496篇 |
专业分类
化学 | 2026篇 |
晶体学 | 26篇 |
力学 | 840篇 |
综合类 | 239篇 |
数学 | 11925篇 |
物理学 | 2707篇 |
出版年
2024年 | 39篇 |
2023年 | 184篇 |
2022年 | 185篇 |
2021年 | 276篇 |
2020年 | 321篇 |
2019年 | 381篇 |
2018年 | 380篇 |
2017年 | 438篇 |
2016年 | 504篇 |
2015年 | 360篇 |
2014年 | 631篇 |
2013年 | 1151篇 |
2012年 | 671篇 |
2011年 | 731篇 |
2010年 | 686篇 |
2009年 | 889篇 |
2008年 | 954篇 |
2007年 | 1018篇 |
2006年 | 903篇 |
2005年 | 843篇 |
2004年 | 705篇 |
2003年 | 628篇 |
2002年 | 652篇 |
2001年 | 566篇 |
2000年 | 514篇 |
1999年 | 526篇 |
1998年 | 416篇 |
1997年 | 380篇 |
1996年 | 300篇 |
1995年 | 215篇 |
1994年 | 183篇 |
1993年 | 136篇 |
1992年 | 130篇 |
1991年 | 107篇 |
1990年 | 80篇 |
1989年 | 64篇 |
1988年 | 59篇 |
1987年 | 55篇 |
1986年 | 52篇 |
1985年 | 79篇 |
1984年 | 71篇 |
1983年 | 27篇 |
1982年 | 54篇 |
1981年 | 30篇 |
1980年 | 43篇 |
1979年 | 37篇 |
1978年 | 26篇 |
1977年 | 25篇 |
1976年 | 17篇 |
1974年 | 10篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
241.
朱方生 《武汉大学学报(理学版)》1995,(3)
构造了线性二次型最优控制的并行算法,介绍了这个并行算法在武汉大学“WUDP91”并行分布式处理系统上试算的数值应用软件的框图.本软件适用于既定动态系统的平衡问题.对于经济系统,可通过政策控制变量来调节和改善其状态和响应.对于自治系统可找出最优控制使得消耗函数达到最小值.通过对一系列例子进行试算,结果证实,所构造的并行算法和相应的数值软件是有效的,其加速比约为7. 相似文献
242.
Lubomír Kubáček 《Mathematica Slovaca》2007,57(1):59-82
In some situations estimates of unknown parameters must be corrected by additional measurements. It is in principle no problem
to calculate the corrected estimates, however, it is of more interest to find formulae for correction itself. The formulae
enable us to design an additional experiment and to judge its usefulness.
The aim of the paper is to find such formulae for several situations.
Supported by the grant of the Council of Czech Government MSM 6 198 959 214. 相似文献
243.
244.
We investigate traces of functions, belonging to a class of functions with dominating mixed smoothness in ℝ3, with respect to planes in oblique position. In comparison with the classical theory for isotropic spaces a few new phenomenona
occur. We shall present two different approaches. One is based on the use of the Fourier transform and restricted to p = 2. The other one is applicable in the general case of Besov-Lizorkin-Triebel spaces and based on atomic decompositions. 相似文献
245.
Frédéric Mynard 《Topology and its Applications》2007,154(4):953-968
Two results on product of compact filters are shown to be the common principle behind a surprisingly large number of theorems. 相似文献
246.
Carlo Carlini Valentina De Luise Anna Maria Raspolli Galletti Glauco Sbrana 《Journal of polymer science. Part A, Polymer chemistry》2006,44(1):200-206
Novel catalytic systems, prepared in situ by the oxidative addition of 8‐hydroxyquinoline ligands to bis(1,5‐cyclooctadiene)nickel(0) and activated by methylaluminoxane, were studied in ethylene polymerization. When 8‐hydroxyquinoline was employed, only oligomeric products were obtained. On the contrary, 5,7‐dinitro‐8‐hydroxyquinoline gave linear polyethylene (PE), but with a modest activity. For the catalyst based on 5‐nitro‐8‐hydroxyquinoline, the productivity was largely dependent on the content of free trimethylaluminum (TMA) present in the commercial aluminoxane. The progressive optimization of the TMA/oligomeric methylaluminoxane ratio increased the productivity, which reached 700 kg of PE/(mol of Ni × h), by an order of magnitude. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 200–206, 2006 相似文献
247.
V. M. Murzina 《Algebra and Logic》2007,46(6):409-418
We study into the question whether calculi associated with Ershov topological spaces possess Craig’s interpolation property.
Supported by RFBR grant No. 06-01-00358, by INTAS grant No. 04-77-7080, and by the Council for Grants (under RF President)
and State Aid of Fundamental Science Schools, project NSh-4787.2006.1.
__________
Translated from Algebra i Logika, Vol. 46, No. 6, pp. 745–762, November–December, 2007. 相似文献
248.
Commutators of singular integrals on spaces of homogeneous type 总被引:1,自引:0,他引:1
In this work we prove some sharp weighted inequalities on spaces of homogeneous type for the higher order commutators of singular
integrals introduced by R. Coifman, R. Rochberg and G. Weiss in Factorization theorems for Hardy spaces in several variables,
Ann. Math. 103 (1976), 611–635. As a corollary, we obtain that these operators are bounded on L
p
(w) when w belongs to the Muckenhoupt’s class A
p
, p > 1. In addition, as an important tool in order to get our main result, we prove a weighted Fefferman-Stein type inequality
on spaces of homogeneous type, which we have not found previously in the literature. 相似文献
249.
建立了Littlewood—Paley g-函数在Heisenberg群上某些Herz型空间上的有界性. 相似文献
250.
Pavol Ševera 《Letters in Mathematical Physics》2006,75(3):273-277
We introduce an affine-invariant version of generating functions of symplectic transformations of affine symplectic spaces,
together with a generalization for other symmetric symplectic spaces. The composition of these functions has a nice connection
with the Moyal product. 相似文献