首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   1831篇
  免费   154篇
  国内免费   175篇
  2024年   3篇
  2023年   38篇
  2022年   33篇
  2021年   39篇
  2020年   54篇
  2019年   83篇
  2018年   61篇
  2017年   72篇
  2016年   63篇
  2015年   75篇
  2014年   124篇
  2013年   114篇
  2012年   98篇
  2011年   113篇
  2010年   78篇
  2009年   104篇
  2008年   106篇
  2007年   107篇
  2006年   112篇
  2005年   67篇
  2004年   82篇
  2003年   70篇
  2002年   81篇
  2001年   51篇
  2000年   39篇
  1999年   28篇
  1998年   33篇
  1997年   16篇
  1996年   29篇
  1995年   21篇
  1994年   21篇
  1993年   22篇
  1992年   11篇
  1991年   12篇
  1990年   7篇
  1989年   9篇
  1988年   10篇
  1987年   3篇
  1986年   8篇
  1985年   11篇
  1984年   8篇
  1983年   5篇
  1982年   6篇
  1980年   12篇
  1979年   2篇
  1978年   5篇
  1977年   3篇
  1975年   2篇
  1974年   3篇
  1972年   3篇
排序方式: 共有2160条查询结果,搜索用时 15 毫秒
1.
Due to the fact that the flood data series of small drainage basins is relatively short, available data are often not sufficient for flood risk analysis. This presents the problem of risk analysis using very small data samples. One method that can be applied is to regard the available small samples as fuzzy information and optimize them using information diffusion technology to yield analytical results with greater reliability. In this article a risk analysis method based on information diffusion theory is applied to create a new flood risk analysis model. Application of the model is illustrated taking the Jinhuajiang and Qujiang drainage basins as examples. This is a new attempt at applying information diffusion theory in flood risk analysis. Computations based on this analytical flood risk model can yield an estimated flood damage value that is relatively accurate. This study indicates that the aforementioned model exhibits fairly stable analytical results, even when using a small set of sample data. The results also indicate that information diffusion technology is highly capable of extracting useful information and therefore improves system recognition accuracy. This method can be easily applied and the analytical results produced are easy to understand. Results are accurate enough to act as a guide in disaster situations.  相似文献   
2.
For the estimation of population mean in simple random sampling, an efficient regression-type estimator is proposed which is more efficient than the conventional regression estimator and hence than mean per unit estimator, ratio and product estimators and many other estimators proposed by various authors. Some numerical examples are included for illustration.  相似文献   
3.
Enzymes are remarkable molecules which make metabolism possible. Their processing powers are considerable for not only are they catalysts they also contribute to information processing, integration, coherence and memory in the cell. This complex of attributes suggests that a complementary perspective to enzyme nature and activity is needed related to what enzymes and verbs have in common. The value of this kind of thinking is that it shifts the focus from objects and mechanisms to processes and information. In order to support this idea a number of features which enzymes and verbs share are discussed including, context-dependence, occurrence, cases, voice, mood and glue/integrative capacities. The paper concludes with some reflections on the utility of a view of enzymes as verbs.  相似文献   
4.
5.
6.
7.
8.
Akaike's information criterion and the histogram   总被引:1,自引:0,他引:1  
TAYLOR  CHARLES C. 《Biometrika》1987,74(3):636-639
  相似文献   
9.
Adjustments to profile likelihood   总被引:1,自引:0,他引:1  
FRASER  D. A. S.; REID  N. 《Biometrika》1989,76(3):477-488
  相似文献   
10.
A note on a semiparametric estimator of mortality   总被引:1,自引:0,他引:1  
  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号