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   1802篇
  免费   103篇
管理学   180篇
民族学   24篇
人口学   258篇
丛书文集   1篇
理论方法论   104篇
综合类   19篇
社会学   864篇
统计学   455篇
  2024年   1篇
  2023年   28篇
  2022年   28篇
  2021年   44篇
  2020年   97篇
  2019年   96篇
  2018年   195篇
  2017年   178篇
  2016年   143篇
  2015年   69篇
  2014年   100篇
  2013年   352篇
  2012年   171篇
  2011年   54篇
  2010年   52篇
  2009年   50篇
  2008年   47篇
  2007年   31篇
  2006年   22篇
  2005年   14篇
  2004年   24篇
  2003年   10篇
  2002年   20篇
  2001年   14篇
  2000年   12篇
  1999年   11篇
  1998年   5篇
  1997年   5篇
  1996年   7篇
  1995年   1篇
  1994年   3篇
  1993年   5篇
  1992年   4篇
  1991年   5篇
  1987年   1篇
  1985年   1篇
  1983年   1篇
  1980年   1篇
  1973年   1篇
  1968年   2篇
排序方式: 共有1905条查询结果,搜索用时 390 毫秒
221.
Using the data collected from research carried out at two Portuguese universities, this article highlights the way university lecturers currently deal with space and time. Their professional activity is not externally subjected to a specific time geometry that defines their working day. Teaching and researching time–spaces are basically task oriented. Furthermore, university lecturers are increasingly requested to perform tasks in very short time periods in order to secure financial support. To a certain extent, this pressure upon their work is facilitated by the use of technology. However, technology also causes a profound reconfiguration of working times and spaces, especially because it allows lecturers to work at any time from anywhere. This not only renders university physical spaces and times virtual, but it also leads to the colonization of several other time–spaces of their social lives. This article analyses the ambivalence and difficulty of managing time–spaces, as described by the lecturers themselves, with the objective of providing a more accurate awareness of the implications of technology on their lives, as well as the hazards of the progressive externalization of academic work, particularly for women.  相似文献   
222.
223.
Resistance training has been shown to be the most effective exercise mode to induce anabolic adaptations in older men and women. Advances in imaging techniques and histochemistry have increased the ability to detect such changes, confirming the high level of adaptability that remains in aging skeletal muscle. This brief review presents a summary of the resistance-training studies that directly compare chronic anabolic responses to training in older (>60 years) men and women. Sixteen studies are summarized, most of which indicate similar relative anabolic responses between older men and women after resistance training. Relatively small sample sizes in most of the interventions limited their ability to detect significant sex differences and should be considered when interpreting these studies. Future research should incorporate larger sample sizes with multiple measurement time points for anabolic responses.  相似文献   
224.
225.
226.
The minimum and maximum order statistics from many of the common bivariate exponential distributions are predominantly generalized mixtures of exponentials; however, the maximum from the Friday and Patil bivariate exponential (FPBVE) model is either a generalized mixture of three or fewer exponentials or a generalized mixture of gamma and exponentials. In this article, we obtain conditions based on the weights and parameters of the generalized mixtures of gamma and one or two exponential distributions that yield legitimate probability models. Furthermore, we analyze properties of the failure rate of the maximum from the FPBVE model. This answers a question raised in Baggs and Nagaraja (1996 Baggs , G. E. , Nagaraja , H. N. ( 1996 ). Reliability properties of order statistics from bivariate exponential distributions . Commun. Statist. Stochastic Mod. 12 : 611631 .[Taylor & Francis Online] [Google Scholar]).  相似文献   
227.
Nonlinear regression models arise when definite information is available about the form of the relationship between the response and predictor variables. Such information might involve direct knowledge of the actual form of the true model or might be represented by a set of differential equations that the model must satisfy. We develop M-procedures for estimating parameters and testing hypotheses of interest about these parameters in nonlinear regression models for repeated measurement data. Under regularity conditions, the asymptotic properties of the M-procedures are presented, including the uniform linearity, normality and consistency. The computation of the M-estimators of the model parameters is performed with iterative procedures, similar to Newton–Raphson and Fisher's scoring methods. The methodology is illustrated by using a multivariate logistic regression model with real data, along with a simulation study.  相似文献   
228.
A new discrete family of probability distributions that are generated by the 3 F 2 function with complex parameters is presented. Some of the properties of this new family are studied as well as methods of estimation for its parameters. It affords considerable flexibility of shape which turns the distribution into an appropriate candidate for modeling data that cannot be adequately fitted by classical families with fewer parameters. Finally, three examples in the fields of Agriculture and Education are included in order to show the versatility and utility of this distribution.  相似文献   
229.
Friday and Patil bivariate exponential (FPBVE) distribution family is one of the most flexible bivariate exponential distributions in the literature; among others, it contains the bivariate exponential models due to Freund, Marshall–Olkin, Block–Basu, and Proschan–Sullo as particular cases. In this article, we discuss the stochastic aging of the maximum statistic from FPBVE model in according to the log-concavity of its density function, i.e., in the increasing or decreasing likelihood ratio classes (ILR or DLR), and consequently in the IFR and DFR classes. Furthermore, a kind of DFR distributions which are not DLR is derived from our classification.  相似文献   
230.
The relationship between contributions and elicited beliefs in a repeated two-person public good experiment is modeled with the help of a parsimounious random-utility function that allows for conditionally cooperative, opportunistic, and altruistic patterns of behavior. Under standard assumptions, a latent-class mixed logit specification with three sub-populations is shown to capture well heterogeneity in individual contribution levels over time, while also accomodating for different degrees of heteroscedasticity. The estimation results are consistent with the conjecture that the majority of players in public goods games are strongly conditional cooperators, with smaller fractions of the population leaning to opportunistic or altruistic behavior.  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