全文获取类型
收费全文 | 2735篇 |
免费 | 429篇 |
国内免费 | 173篇 |
专业分类
化学 | 363篇 |
晶体学 | 32篇 |
力学 | 291篇 |
综合类 | 107篇 |
数学 | 1279篇 |
物理学 | 1265篇 |
出版年
2024年 | 6篇 |
2023年 | 29篇 |
2022年 | 78篇 |
2021年 | 72篇 |
2020年 | 56篇 |
2019年 | 66篇 |
2018年 | 52篇 |
2017年 | 113篇 |
2016年 | 123篇 |
2015年 | 82篇 |
2014年 | 171篇 |
2013年 | 178篇 |
2012年 | 128篇 |
2011年 | 160篇 |
2010年 | 155篇 |
2009年 | 176篇 |
2008年 | 201篇 |
2007年 | 180篇 |
2006年 | 162篇 |
2005年 | 157篇 |
2004年 | 102篇 |
2003年 | 116篇 |
2002年 | 89篇 |
2001年 | 87篇 |
2000年 | 92篇 |
1999年 | 71篇 |
1998年 | 62篇 |
1997年 | 45篇 |
1996年 | 50篇 |
1995年 | 45篇 |
1994年 | 31篇 |
1993年 | 32篇 |
1992年 | 29篇 |
1991年 | 26篇 |
1990年 | 19篇 |
1989年 | 16篇 |
1988年 | 24篇 |
1987年 | 13篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 14篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有3337条查询结果,搜索用时 31 毫秒
31.
V. N. Lopatin A. D. Aponasenko N. V. Shepelevich 《Journal of Applied Spectroscopy》1997,64(6):825-831
We investigate the possibilities of creating a method for estimating the optical constants, dimensions, and concentrations
of “soft” absorbing particles by applying a theoretical analysis of the angular dependence of the intergrated indicatrix,
overall characteristics of light scattering, and absorption on the phase shift and diffraction parameter of particles in the
brightening band region. We show that using the investigated optical characteristics, it is possible to determine the unknown
parameters of a suspension from experimental data.
Institute of Biophysics, Siberian Branch of the Russian Academy of Sciences, Akademgorodok, Krasnoyarsk, 660036, Russia. Translated
from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 6, pp. 807–812, November–December, 1997. 相似文献
32.
33.
提出了一种非刚性点匹配的算法并把其运用于医学图像配准.该算法采用信号滤波的方法来获得点集间的匹配信息,并运用松弛标记法将各点邻域关系对模糊的匹配信息进行迭代获得明确的匹配关系.在此基础上,利用高斯径向基函数来描述点模式间的弹性形变,在基本的迭代框架下实现问题的求解.实验结果显示在形变程度为5%、出格点比率50%和噪声标准差为5%的情况下该算法的匹配误差能控制在0.13以下,表明了该算法的鲁棒性和有效性,较好地解决了医学非刚性形变的点匹配问题. 相似文献
34.
A new Co–Fe-based ferromagnetic bulk metallic glass (BMG) was synthesized by copper mould casting method. The thermal stability and crystallization processes were investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The soft magnetic behavior was studied by DC magnetic measurements. The high glass formation ability was interpreted in terms of the effective suppression of nucleation and growth of the intermetallic compounds which appear in the multicomponent system during solidification. The high thermal stability indicates that the new Co–Fe-based BMG could be used as high-temperature magnetic material. The low coercivity which was as low as 8 A/m for the as-cast sample was found in the Co–Fe-based metallic glass cylinder with a diameter of 1.5 mm. 相似文献
35.
36.
For structural parameters with uncertainties, interval mathematics can, in the case where the probabilistic distribution density
of uncertain variables is unavailable, deal with the influence of uncertainties in structural parameters on the response of
structures. In order to evaluate the region containing natural frequencies of structures with interval parameters, the interval
parameter perturbation method is presented in this paper. The advantage of the present method is its computational efficiency
in evaluating the region containing natural frequencies. A numerical example is used to illustrate the efficiency of the method
proposed.
The project is supported by National Youth Natural Science Foundation of China and National Outstanding Youth Science Foundation
of China. 相似文献
37.
Boguslaw Zegarliński 《Journal of statistical physics》1986,43(3-4):687-705
We give a condition on a Gibbs measure for an attractive Markov specification, which assures extremality and the global Markov property. As an example of application we consider the class of attractive Markov specifications defined on a compact configuration space over a two-dimensional lattice by the interaction Hamiltonians (assumed to have a finite set of periodic ground configurations) satisfying Peierl's condition. We prove that each extremal Gibbs measure for such a specification, at sufficiently low temperature, has the global Markov property.On leave of absence from the Institute of Theoretical Physics, University of Wrocaw, Poland. 相似文献
38.
39.
The perfect matching vector and forcing and the Kekulé-vector of cata-benzenoids are defined. Two theorems are given which
set the sufficient and necessary conditions for HKZ-vector (Harary et al. J Math Chem 6:295, 1991) and Kekulé-vector in cata-benzenoids.
Additional two theorems are obtained which give sharp bounds for the modules of HKZ- and Kekulé vectors.
Dedicated to Professor Tadeusz Marek Krygowski on the happy occasion of his 70th birthday. 相似文献
40.
The Randić index of an organic molecule whose molecular graph is G is the sum of the weights (d(u)d(v))−1/2 of all edges uv of G, where d(u) and d(v) are the degrees of the vertices u and v in G. We give a sharp lower bound on the Randić index of conjugated trees (trees with a perfect matching) in terms of the number
of vertices. A sharp lower bound on the Randić index of trees with a given size of matching is also given
Mei Lu: Partially supported by NNSFC (No. 60172005)
Lian-zhu Zhang: Partially supported by NNSFC (No. 10271105)
Feng Tian: Partially supported by NNSFC (No. 10431020) 相似文献