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   847篇
  免费   54篇
管理学   122篇
民族学   9篇
人才学   1篇
人口学   51篇
丛书文集   2篇
理论方法论   111篇
综合类   4篇
社会学   499篇
统计学   102篇
  2023年   10篇
  2022年   9篇
  2021年   8篇
  2020年   22篇
  2019年   35篇
  2018年   39篇
  2017年   46篇
  2016年   46篇
  2015年   37篇
  2014年   35篇
  2013年   180篇
  2012年   32篇
  2011年   44篇
  2010年   24篇
  2009年   32篇
  2008年   34篇
  2007年   27篇
  2006年   21篇
  2005年   16篇
  2004年   16篇
  2003年   13篇
  2002年   14篇
  2001年   16篇
  2000年   12篇
  1999年   10篇
  1998年   8篇
  1997年   4篇
  1996年   4篇
  1995年   4篇
  1994年   11篇
  1993年   5篇
  1992年   9篇
  1991年   9篇
  1990年   5篇
  1989年   4篇
  1988年   5篇
  1987年   7篇
  1986年   3篇
  1985年   3篇
  1984年   3篇
  1983年   5篇
  1982年   5篇
  1981年   5篇
  1980年   6篇
  1979年   3篇
  1978年   2篇
  1977年   3篇
  1976年   2篇
  1973年   2篇
  1968年   1篇
排序方式: 共有901条查询结果,搜索用时 15 毫秒
1.
As part of the celebration of the 40th anniversary of the Society for Risk Analysis and Risk Analysis: An International Journal, this essay reviews the 10 most important accomplishments of risk analysis from 1980 to 2010, outlines major accomplishments in three major categories from 2011 to 2019, discusses how editors circulate authors’ accomplishments, and proposes 10 major risk-related challenges for 2020–2030. Authors conclude that the next decade will severely test the field of risk analysis.  相似文献   
2.
Presidential elections are often seen as referendums on the health of the economy; however, little evidence exists on the president's ability to influence gross domestic product (GDP). This study examines the effect of the incentive to be reelected and the resulting increase in presidential effort on GDP growth. Growth is found to rise in reelection years for first‐term presidents after 1932 and to fall in election years before 1932, when reelection was uncommon, and for second‐term presidents generally. This effect is largest for high‐quality presidents—who probably have the highest return to effort—and is spread across multiple sectors of the economy. (JEL D78, D72, E32, J24)  相似文献   
3.
Extensive sibling conflict is predictive of multiple poor adjustment outcomes during adolescence and early adulthood, but the frequency and developmental impact of such conflict may be conditional on ineffective parenting. Thus, sibling conflict may add to or amplify the negative effects of ineffective parenting on adolescent boys' adjustment. Hypotheses in this study were that: (a) multiple informant measures of problematic parent–child relationships and of sibling conflict would form distinct constructs rather than a single negative family process construct, and (b) ineffective parenting, sibling conflict, and their interaction measured at ages 10 to 12 would predict boys' concurrent status and developmental trajectories for antisocial behavior and peer adjustment across a 4‐year span from ages 12 to 16. Confirmatory factor and latent growth modeling analyses were consistent with these hypotheses, demonstrating the important developmental impact of sibling conflict.  相似文献   
4.
5.
6.
In non-experimental research, data on the same population process may be collected simultaneously by more than one instrument. For example, in the present application, two sample surveys and a population birth registration system all collect observations on first births by age and year, while the two surveys additionally collect information on women’s education. To make maximum use of the three data sources, the survey data are pooled and the population data introduced as constraints in a logistic regression equation. Reductions in standard errors about the age and birth-cohort parameters of the regression equation in the order of three-quarters are obtained by introducing the population data as constraints. A halving of the standard errors about the education parameters is achieved by pooling observations from the larger survey dataset with those from the smaller survey. The percentage reduction in the standard errors through imposing population constraints is independent of the total survey sample size.  相似文献   
7.
This article introduces a new model for transaction prices in the presence of market microstructure noise in order to study the properties of the price process on two different time scales, namely, transaction time where prices are sampled with every transaction and tick time where prices are sampled with every price change. Both sampling schemes have been used in the literature on realized variance, but a formal investigation into their properties has been lacking. Our empirical and theoretical results indicate that the return dynamics in transaction time are very different from those in tick time and the choice of sampling scheme can therefore have an important impact on the properties of realized variance. For RV we find that tick time sampling is superior to transaction time sampling in terms of mean-squared-error, especially when the level of noise, number of ticks, or the arrival frequency of efficient price moves is low. Importantly, we show that while the microstructure noise may appear close to IID in transaction time, in tick time it is highly dependent. As a result, bias correction procedures that rely on the noise being independent, can fail in tick time and are better implemented in transaction time.  相似文献   
8.
Several methods exist for the problem of testing the equality of several treatments against the one-sided alternative that the treatments are better than the control. These methods include Dunnett's test, Bartholomew's likelihood-ratio test, the Abelson-Tukey-Schaafsma-Smid optimal-contrast test, and the multiple-contrast test of Mukerjee, Robertson, and Wright. A new test is proposed based on an approximation of the likelihood-ratio test of Bartholomew. This test involves using a circular cone in place of the alternative-hypothesis cone. The circular-cone test has excellent power characteristics similar to those of Bartholomew's test. Moreover, it has the advantages of being simpler to compute and may be used with unequal sample sizes.  相似文献   
9.
10.
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