全文获取类型
收费全文 | 2662篇 |
免费 | 274篇 |
国内免费 | 261篇 |
专业分类
化学 | 315篇 |
晶体学 | 6篇 |
力学 | 140篇 |
综合类 | 66篇 |
数学 | 1800篇 |
物理学 | 870篇 |
出版年
2023年 | 23篇 |
2022年 | 34篇 |
2021年 | 41篇 |
2020年 | 69篇 |
2019年 | 70篇 |
2018年 | 61篇 |
2017年 | 74篇 |
2016年 | 84篇 |
2015年 | 43篇 |
2014年 | 116篇 |
2013年 | 205篇 |
2012年 | 147篇 |
2011年 | 137篇 |
2010年 | 136篇 |
2009年 | 188篇 |
2008年 | 193篇 |
2007年 | 177篇 |
2006年 | 145篇 |
2005年 | 134篇 |
2004年 | 134篇 |
2003年 | 125篇 |
2002年 | 111篇 |
2001年 | 91篇 |
2000年 | 71篇 |
1999年 | 73篇 |
1998年 | 70篇 |
1997年 | 60篇 |
1996年 | 65篇 |
1995年 | 42篇 |
1994年 | 35篇 |
1993年 | 23篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 23篇 |
1989年 | 19篇 |
1988年 | 13篇 |
1987年 | 13篇 |
1986年 | 13篇 |
1985年 | 16篇 |
1984年 | 11篇 |
1983年 | 7篇 |
1982年 | 11篇 |
1981年 | 4篇 |
1980年 | 8篇 |
1979年 | 11篇 |
1978年 | 8篇 |
1977年 | 3篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1936年 | 2篇 |
排序方式: 共有3197条查询结果,搜索用时 281 毫秒
51.
We propose a minimum mean absolute error linear interpolator (MMAELI), based on theL
1 approach. A linear functional of the observed time series due to non-normal innovations is derived. The solution equation
for the coefficients of this linear functional is established in terms of the innovation series. It is found that information
implied in the innovation series is useful for the interpolation of missing values. The MMAELIs of the AR(1) model with innovations
following mixed normal andt distributions are studied in detail. The MMAELI also approximates the minimum mean squared error linear interpolator (MMSELI)
well in mean squared error but outperforms the MMSELI in mean absolute error. An application to a real series is presented.
Extensions to the general ARMA model and other time series models are discussed.
This research was supported by a CityU Research Grant and Natural Science Foundation of China. 相似文献
52.
In this paper,the authors obtain the Backlund transformation on time-like surfaces with constant mean curvature in R2,1.Using this transformation,families of surfaces with constant mean curvature from known ones can be constructed. 相似文献
53.
54.
Yuzo Maruyama 《Journal of multivariate analysis》2004,88(2):320-334
We consider estimation of a multivariate normal mean vector under sum of squared error loss.We propose a new class of minimax admissible estimator which are generalized Bayes with respect to a prior distribution which is a mixture of a point prior at the origin and a continuous hierarchical type prior. We also study conditions under which these generalized Bayes minimax estimators improve on the James–Stein estimator and on the positive-part James–Stein estimator. 相似文献
55.
56.
57.
Periodica Mathematica Hungarica - Let X 1,X 2,... be a sequence of independent and identically distributed random variables, and put % MATHTYPE!MTEF!2!1!+-%... 相似文献
58.
B.E. Rhoades 《Journal of Mathematical Analysis and Applications》2003,277(1):375-378
We modify some of the conditions of the theorem to make it more applicable. 相似文献
59.
Another generalization of the Mitrinovic-Djokovic inequality is proved by elementarymeans. 相似文献
60.
Qiji J. Zhu 《Set-Valued Analysis》1998,6(2):171-185
Several different basic tools are used for studying subdifferentials. They are a nonlocal fuzzy sum rule in (Borwein et al., 1996; Zhu, 1996), a multidirectional mean value theorem in (Clarke and Ledyaev, 1994; Clarke et al., 1998), local fuzzy sum rules in (Ioffe, 1984, 1990) and an extremal principle in (Kruger and Mordukhovich, 1980; Mordukhovich, 1976, 1980, 1994). We show that all these basic results are equivalent and discuss some interesting consequences of this equivalence. 相似文献