全文获取类型
收费全文 | 2359篇 |
免费 | 210篇 |
国内免费 | 382篇 |
专业分类
化学 | 196篇 |
晶体学 | 9篇 |
力学 | 210篇 |
综合类 | 52篇 |
数学 | 1946篇 |
物理学 | 538篇 |
出版年
2024年 | 7篇 |
2023年 | 21篇 |
2022年 | 35篇 |
2021年 | 50篇 |
2020年 | 53篇 |
2019年 | 62篇 |
2018年 | 62篇 |
2017年 | 68篇 |
2016年 | 55篇 |
2015年 | 48篇 |
2014年 | 83篇 |
2013年 | 333篇 |
2012年 | 80篇 |
2011年 | 113篇 |
2010年 | 94篇 |
2009年 | 108篇 |
2008年 | 164篇 |
2007年 | 159篇 |
2006年 | 152篇 |
2005年 | 106篇 |
2004年 | 113篇 |
2003年 | 124篇 |
2002年 | 113篇 |
2001年 | 107篇 |
2000年 | 93篇 |
1999年 | 89篇 |
1998年 | 95篇 |
1997年 | 67篇 |
1996年 | 58篇 |
1995年 | 47篇 |
1994年 | 43篇 |
1993年 | 22篇 |
1992年 | 17篇 |
1991年 | 16篇 |
1990年 | 20篇 |
1989年 | 13篇 |
1988年 | 11篇 |
1987年 | 8篇 |
1986年 | 11篇 |
1985年 | 4篇 |
1984年 | 12篇 |
1983年 | 1篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1972年 | 1篇 |
1971年 | 2篇 |
1936年 | 2篇 |
排序方式: 共有2951条查询结果,搜索用时 15 毫秒
101.
Canonical correlation analysis (CCA) is one of popular statistical methodologies in multivariate analysis, especially, in studying relation of two sets of variables. However, if sample sizes are smaller than the maximum of the dimensions of two sets of variables, it is not plausible to construct canonical coefficient matrices due to failure of inverting sample covariance matrices. In this article, we develop a two step procedure of CCA implemented in such situation. For this, seeded dimension reduction is adapted into CCA. Numerical studies confirm the approach, and two real data analyses are presented. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
102.
Vasudevan Lakshminarayanan Cindhuja Chockalingam Dr. Eduardo Mendes Dr. Prof. Jan H. van Esch 《Chemphyschem》2021,22(21):2256-2261
Properties such as shear modulus, gelation time, structure of supramolecular hydrogels are strongly dependent on self-assembly, gelation triggering mechanism and processes used to form the gel. In our work we extend reported rheology analysis methodologies to pH-triggered supramolecular gels to understand structural insight using a model system based on N−N’ Dibenzoyl-L-Cystine pH-triggered hydrogelator and Glucono-δ-Lactone as the trigger. We observed that Avrami growth model when applied to time-sweep rheological data of gels formed at lower trigger concentrations provide estimates of fractal dimension which agree well compared with visualization of the microstructure as seen via Confocal Laser Scanning Microscopy, for a range of gelator concentrations. 相似文献
103.
李玉山 《原子与分子物理学报》2015,32(6)
基于Thomas-Fermi半经典近似方法研究了谐振子势阱约束下任意维理想玻色气体的玻色-爱因斯坦凝聚(BEC).导出了玻色气体的BEC转变温度、基态粒子占据比例、内能和热容量等物理量的解析表达式,讨论了空间维度和谐振子势阱的影响.以二维和三维玻色系统为例,数值计算了上述热力学量,并与解析结果进行了对比,二者获得了较好的吻合. 相似文献
104.
This paper aims to determine the minimal dimensions and super-dimensions of faithful representations for Heisenberg Lie superalgebras over an algebraically closed field of characteristic zero. 相似文献
105.
106.
Teng Xia Ju 《数学学报(英文版)》2009,25(5):831-844
In this paper, we show that if H is a finite-dimensional Hopf algebra such that H and H^* are semisimple, then gl.dim(A#σH)=gl.dim(A), where a is a convolution invertible cocycle. We also discuss the relationship of global dimensions between the crossed product A^#σH and the algebra A, where A is coacted by H. Dually, we give a sufficient condition for a finite dimensional coalgebra C and a finite dimensional semisimple Hopf algebra H such that gl.dim(C α H)=gl.dim(C). 相似文献
107.
Abigail C. Bailey 《代数通讯》2017,45(6):2662-2672
We extend the definition of a piecewise Noetherian ring to the noncommutative case, and investigate various properties of such rings. In particular, we show that a ring with Krull dimension is piecewise Noetherian. Certain fully bounded piecewise Noetherian rings have Gabriel dimension and exhibit the Gabriel correspondence between prime ideals and indecomposable injective modules. 相似文献
108.
109.
PARK Kyewon Koh 《中国科学 数学(英文版)》2011,(3):531-538
We introduce the notion of entropy generating sequence for infinite words and define its dimension when it exists. We construct an entropy generating sequence for each symbolic example constructed by Cassaigne such that the dimension of the sequence is the same as its topological entropy dimension. Hence the complexity can be measured via the dimension of an entropy generating sequence. Moreover, we construct a weakly mixing example with subexponential growth rate. 相似文献
110.