全文获取类型
收费全文 | 4374篇 |
免费 | 70篇 |
国内免费 | 102篇 |
专业分类
化学 | 332篇 |
晶体学 | 5篇 |
力学 | 123篇 |
综合类 | 23篇 |
数学 | 2961篇 |
物理学 | 1102篇 |
出版年
2024年 | 4篇 |
2023年 | 26篇 |
2022年 | 29篇 |
2021年 | 36篇 |
2020年 | 54篇 |
2019年 | 41篇 |
2018年 | 37篇 |
2017年 | 55篇 |
2016年 | 71篇 |
2015年 | 84篇 |
2014年 | 169篇 |
2013年 | 252篇 |
2012年 | 201篇 |
2011年 | 262篇 |
2010年 | 195篇 |
2009年 | 309篇 |
2008年 | 294篇 |
2007年 | 300篇 |
2006年 | 249篇 |
2005年 | 166篇 |
2004年 | 144篇 |
2003年 | 126篇 |
2002年 | 147篇 |
2001年 | 185篇 |
2000年 | 141篇 |
1999年 | 124篇 |
1998年 | 129篇 |
1997年 | 73篇 |
1996年 | 66篇 |
1995年 | 73篇 |
1994年 | 27篇 |
1993年 | 32篇 |
1992年 | 28篇 |
1991年 | 26篇 |
1990年 | 25篇 |
1989年 | 28篇 |
1988年 | 19篇 |
1987年 | 19篇 |
1986年 | 16篇 |
1985年 | 57篇 |
1984年 | 56篇 |
1983年 | 26篇 |
1982年 | 40篇 |
1981年 | 39篇 |
1980年 | 28篇 |
1979年 | 16篇 |
1978年 | 8篇 |
1977年 | 5篇 |
1976年 | 3篇 |
1974年 | 2篇 |
排序方式: 共有4546条查询结果,搜索用时 331 毫秒
1.
2.
Accuracy arguments are the en vogue route in epistemic justifications of probabilism and further norms governing rational belief. These arguments often depend on the fact that the employed inaccuracy measure is strictly proper. I argue controversially that it is ill-advised to assume that the employed inaccuracy measures are strictly proper and that strictly proper statistical scoring rules are a more natural class of measures of inaccuracy. Building on work in belief elicitation I show how strictly proper statistical scoring rules can be used to give an epistemic justification of probabilism.An agent's evidence does not play any role in these justifications of probabilism. Principles demanding the maximisation of a generalised entropy depend on the agent's evidence. In the second part of the paper I show how to simultaneously justify probabilism and such a principle. I also investigate scoring rules which have traditionally been linked with entropies. 相似文献
3.
Laser welding is one of the most precise welding processes in joining sheet metals. In laser welding, performing real time evaluation of the welding quality is very important to enhance the efficiency of the welding process. In this study, the plasma and spatter, which are generated during laser welding, are measured using UV and IR photodiodes. The factors that influence weld quality are classified into five categories; optimal heat input, slightly low heat input, low heat input, partial joining due to gap mismatch, and nozzle deviation. The data number deviated from reference signals and their standard deviations were also considered to evaluate the qualities. A system was also formulated to perform real time evaluations of the weld quality using a fuzzy multi-feature pattern recognition with the measured signals. 相似文献
4.
The radiation emitted by charged, scalar particles in a Schwarzschild field with maximal acceleration corrections is calculated classically and in the tree approximation of quantum field theory. In both instances the particles emit radiation that has characteristics similar to those of gamma-ray bursters. 相似文献
5.
自Tanaka等1982年提出模糊回归概念以来,该问题已得到广泛的研究。作为主要估计方法之一的模糊最小二乘估计以其与统计最小二乘估计的密切联系更受到人们的重视。本文依据适当定义的两个模糊数之间的距离,提出了模糊线性回归模型的一个约束最小二乘估计方法,该方法不仅能使估计的模糊参数的宽度具有非负性而且估计的模糊参数的中心线与传统的最小二乘估计相一致。最后,通过数值例子说明了所提方法的具体应用。 相似文献
6.
7.
Benjamin J. K. Evans Susan M. Scott Antony C. Searle 《General Relativity and Gravitation》2002,34(10):1675-1684
We have developed a new tool for numerical work in General Relativity: GRworkbench. We discuss how GRworkbench's implementation of a numerically-amenable analogue to Differential Geometry facilitates the development of robust and chart-independent numerical algorithms. We consider, as an example, geodesic tracing on two charts covering the exterior Schwarzschild space-time. 相似文献
8.
9.
10.
Piotr Garbaczewski 《Journal of statistical physics》2006,123(2):315-355
We analyze the functioning of Gibbs-type entropy functionals in the time domain, with emphasis on Shannon and Kullback-Leibler entropies of time-dependent continuous probability distributions. The Shannon entropy validity is extended to probability distributions inferred from L
2(R
n
) quantum wave packets. In contrast to the von Neumann entropy which simply vanishes on pure states, the differential entropy quantifies the degree of probability (de)localization and its time development. The associated dynamics of the Fisher information functional quantifies nontrivial power transfer processes in the mean, both in dissipative and quantum mechanical cases.
PACS NUMBERS: 05.45.+b, 02.50.-r, 03.65.Ta, 03.67.-a 相似文献