全文获取类型
收费全文 | 901篇 |
免费 | 19篇 |
国内免费 | 10篇 |
专业分类
化学 | 561篇 |
晶体学 | 6篇 |
力学 | 7篇 |
数学 | 56篇 |
物理学 | 300篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 4篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 15篇 |
2013年 | 29篇 |
2012年 | 50篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 39篇 |
2008年 | 39篇 |
2007年 | 40篇 |
2006年 | 43篇 |
2005年 | 43篇 |
2004年 | 37篇 |
2003年 | 33篇 |
2002年 | 42篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 10篇 |
1998年 | 10篇 |
1997年 | 9篇 |
1996年 | 14篇 |
1995年 | 16篇 |
1994年 | 24篇 |
1993年 | 8篇 |
1992年 | 10篇 |
1991年 | 6篇 |
1990年 | 8篇 |
1989年 | 13篇 |
1988年 | 13篇 |
1987年 | 11篇 |
1986年 | 7篇 |
1985年 | 20篇 |
1984年 | 6篇 |
1983年 | 11篇 |
1982年 | 8篇 |
1981年 | 12篇 |
1980年 | 6篇 |
1979年 | 12篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1975年 | 9篇 |
1974年 | 7篇 |
1973年 | 9篇 |
1972年 | 13篇 |
排序方式: 共有930条查询结果,搜索用时 703 毫秒
101.
Strain concentrations associated with the presence of a microvascular network in a polymer matrix are measured using fluorescent
digital image correlation (FDIC). The accuracy of the measurement technique is established for a specimen containing only
a single microchannel. The influence of localized particle reinforcement around the channel is also investigated using this
simplified geometry. Three-dimensional network specimens with different structural designs were fabricated and loaded in uniaxial
tension. The resulting strain concentrations are compared as a function of channel spacing and location. As expected, decreasing
channel spacing leads to increased strain local to the channels. In addition, the three-dimensional nature of the channel
architecture influences the resulting strain. The results provide insight into the mechanical behavior of microvascular networks
and demonstrate the utility of FDIC as a characterization tool at these length scales. 相似文献
102.
103.
104.
We propose the IIPS framework for specifying inductive inference problems. Unlike the specification outline given in [1], the IIPS framework is formally defined and can specify problems where the inducer influences the presentation order of the examples. The framework is suited to specifying machine-discovery problems. 相似文献
105.
D. H. Hamilton 《Journal d'Analyse Mathématique》1994,63(1):333-348
Research supported in part by the National Science Foundation. 相似文献
106.
107.
108.
In 1974 J.A. Thas constructed a class of maximal arcs in certain translation planes of order q2. We characterise these as being exactly those (non-trivial) maximal arcs that are stabilised by an homology of order q– 1.The first author gratefully acknowledges the support of an Australian Postgraduate Research Award. 相似文献
109.
Mazzocchi C Grzywacz R Liddick SN Rykaczewski KP Schatz H Batchelder JC Bingham CR Gross CJ Hamilton JH Hwang JK Ilyushkin S Korgul A Królas W Li K Page RD Simpson D Winger JA 《Physical review letters》2007,98(21):212501
An alpha-decay branch of (1.4+/-0.4) x 10(-4) has been discovered in the decay of 109I, which predominantly decays via proton emission. The measured Q(alpha) value of 3918+/-21 keV allows the indirect determination of the Q value for proton emission from 105Sb of 356+/-22 keV, which is approximately of 130 keV more bound than previously reported. This result is relevant for the astrophysical rapid proton-capture process, which would terminate in the 105Sn(p,gamma)106Sb(p,gamma)107Te(alpha decay)103Sn cycle at the densities expected in explosive hydrogen burning scenarios, unless unusually strong pairing effects result in a 103Sn(p,gamma)104Sb(p,gamma)105Te(alpha decay)101Sn) cycle. 相似文献
110.
Previous experimental and finite element studies have shown the influence of both soil initial conditions and blade operating conditions on cutting forces. However, most of these finite element analyses (FEA) are limited to small blade displacements to reduce element distortion which can cause solution convergence problems. In this study a dynamic three-dimensional FEA of soil–tool interaction was carried out based on predefined failure surfaces to investigate the effect of cutting speed and angle on cutting forces over large blade displacements. Sandy soil was considered in this study and modeled using the hypoplastic constitutive model implemented in the commercial FEA package, ABAQUS. Results reveal the validity of the concept of predefined failure surfaces in simulating soil–tool interaction and the significant effect of cutting acceleration on cutting forces. 相似文献