全文获取类型
收费全文 | 4713篇 |
免费 | 385篇 |
国内免费 | 483篇 |
专业分类
化学 | 1029篇 |
晶体学 | 13篇 |
力学 | 1082篇 |
综合类 | 95篇 |
数学 | 2066篇 |
物理学 | 1296篇 |
出版年
2024年 | 9篇 |
2023年 | 55篇 |
2022年 | 113篇 |
2021年 | 157篇 |
2020年 | 143篇 |
2019年 | 135篇 |
2018年 | 142篇 |
2017年 | 207篇 |
2016年 | 277篇 |
2015年 | 184篇 |
2014年 | 231篇 |
2013年 | 371篇 |
2012年 | 205篇 |
2011年 | 256篇 |
2010年 | 238篇 |
2009年 | 284篇 |
2008年 | 275篇 |
2007年 | 239篇 |
2006年 | 244篇 |
2005年 | 225篇 |
2004年 | 216篇 |
2003年 | 177篇 |
2002年 | 155篇 |
2001年 | 133篇 |
2000年 | 125篇 |
1999年 | 109篇 |
1998年 | 101篇 |
1997年 | 88篇 |
1996年 | 66篇 |
1995年 | 64篇 |
1994年 | 63篇 |
1993年 | 32篇 |
1992年 | 28篇 |
1991年 | 29篇 |
1990年 | 29篇 |
1989年 | 18篇 |
1988年 | 22篇 |
1987年 | 18篇 |
1986年 | 16篇 |
1985年 | 20篇 |
1984年 | 17篇 |
1982年 | 13篇 |
1981年 | 4篇 |
1980年 | 6篇 |
1979年 | 11篇 |
1978年 | 9篇 |
1977年 | 6篇 |
1976年 | 2篇 |
1974年 | 5篇 |
1973年 | 4篇 |
排序方式: 共有5581条查询结果,搜索用时 15 毫秒
31.
Peter Amrhein 《Annals of the Institute of Statistical Mathematics》1995,47(1):167-170
Although the theory of rank tests is rather complete in the one-sided case, it was not even known in 1959, whether the Wilcoxon two-sample test and other similar tests are unbiased against the two-sided alternatives (Lehmann (1959,Testing Statistical Hypotheses, p. 240, Wiley, New York)). A partial answer to this question was given by Sugiura in 1965, who found, that the test named above may be biased (Sugiura (1965,Ann. Inst. Statist. Math.,17, 261–263)). According to Lehmann (1986,Testing Statistical Hypotheses, 2nd ed., pp. 322–324, Wiley, New York) it seems to be still open, whether the same is true for the WILCOXON one-sample test, which is also known as WILCOXON signed rank test. This will be shown in the present paper. 相似文献
32.
Testing for additivity with B-splines 总被引:1,自引:0,他引:1
Regression splines are often used for fitting nonparametric functions, and they work especially well for additivity models. In this paper, we consider two simple tests of additivity: an adaptation of Tukey's one degree of freedom test and a nonparametric version of Rao's score test. While the Tukey-type test can detect most forms of the local non-additivity at the parametric rate of O(n-1/2), the score test is consistent for all alternative at a nonparametric rate. The asymptotic distribution of these test statistics is derived under both the null and local alternative hypotheses. A simulation study is conducted to compare their finite-sample performances with some existing kernel-based tests. The score test is found to have a good overall performance. 相似文献
33.
Endoscopic Observation of Tissue by Narrowband Illumination 总被引:6,自引:0,他引:6
Kazuhiro Gono Kenji Yamazaki Nobuyuki Doguchi Tetsuo Nonami Takashi Obi Masahiro Yamaguchi Nagaaki Ohyama Hirohisa Machida Yasushi Sano Shigeaki Yoshida Yasuo Hamamoto Takao Endo 《Optical Review》2003,10(4):211-215
We propose a new illumination method for a medical endoscope: narrow band imaging (NBI), in which the spectral bandwidth of the filtered light is narrowed. To confirm how the spectral specifications of the filtered light influence a reproduced image, an experiment was conducted observing the endoscopic images of the back mucosa of a human tongue. In addition, the effect of NBI on endoscopic images was investigated through preliminary clinical tests in colonoscopy and upper gastrointestinal endoscopy. It has been shown that NBI can enhance the capillary pattern and the crypt pattern on the mucosa. These patterns are useful features for diagnosing an early cancer. 相似文献
34.
Florence Newberger 《Geometriae Dedicata》2003,97(1):215-249
The goal of this paper is to provide a tool, the Global Measure Formula, that will facilitate the study of the limit set of discrete geometrically finite groups of isometries of the rank one symmetric spaces. We consider the shadow of a ball from a fixed reference point onto the boundary, and prove a formula that describes the measure of the shadow in terms of the center of the shadowed ball, generalizing a result from real hyperbolic geometry. 相似文献
35.
36.
SXDG—1型汽车前照灯全自动检测仪是用于检测汽车前照大灯光轴的偏斜情况及发光强度并进行定量检验的专用设备。它可以自动测出有关参数,并予以数字显示和打印输出。本文介绍了该仪器的主要性能、工作原理及微机控制系统(包括硬件结构和软件设计思想等)。 相似文献
37.
In this paper, a successive supersymmetric rank‐1 decomposition of a real higher‐order supersymmetric tensor is considered. To obtain such a decomposition, we design a greedy method based on iteratively computing the best supersymmetric rank‐1 approximation of the residual tensors. We further show that a supersymmetric canonical decomposition could be obtained when the method is applied to an orthogonally diagonalizable supersymmetric tensor, and in particular, when the order is 2, this method generates the eigenvalue decomposition for symmetric matrices. Details of the algorithm designed and the numerical results are reported in this paper. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
38.
物理实验课程考核、评估体系初探 总被引:4,自引:0,他引:4
对物理实验课程考核、评估方法进行了探讨,提出了物理实验课程考核、评估体系及实施细则.重点介绍了体系中的核心部分——正规的物理实验课程考试. 相似文献
39.
基于离差最大化原理的灰色综合评判方法及其应用 总被引:9,自引:0,他引:9
在灰色综合隶属度评价方法基础上,按照离差最大化原理,提出了一种品种区域试验的新的确定权重的方法.应用这种方法,对2002-2003年度国家黄淮南片小麦冬水组区域试验进行了分析.结果表明,这种分析方法克服了通常专家调查法和层次分析法主观随意性强的缺点,因而其分析结果更加客观、可靠.大面积生产实践也表明该方法具有一定可行性和有效性. 相似文献
40.
We consider goodness of fit tests for the Rayleigh distribution with grouped data. New Kolmogrov–Smirnov type tests are suggested and compared with the traditional chi-square and likelihood ratio tests. The results show that some of the suggested tests have a good power performance as compared with the traditional ones. 相似文献