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   8878篇
  免费   342篇
  国内免费   102篇
管理学   590篇
劳动科学   5篇
民族学   64篇
人才学   1篇
人口学   134篇
丛书文集   799篇
理论方法论   306篇
综合类   6472篇
社会学   278篇
统计学   673篇
  2024年   47篇
  2023年   94篇
  2022年   142篇
  2021年   140篇
  2020年   194篇
  2019年   200篇
  2018年   179篇
  2017年   187篇
  2016年   245篇
  2015年   239篇
  2014年   509篇
  2013年   481篇
  2012年   662篇
  2011年   670篇
  2010年   523篇
  2009年   507篇
  2008年   550篇
  2007年   653篇
  2006年   604篇
  2005年   536篇
  2004年   460篇
  2003年   434篇
  2002年   298篇
  2001年   285篇
  2000年   173篇
  1999年   66篇
  1998年   39篇
  1997年   32篇
  1996年   28篇
  1995年   36篇
  1994年   16篇
  1993年   20篇
  1992年   19篇
  1991年   13篇
  1990年   10篇
  1989年   15篇
  1988年   5篇
  1987年   4篇
  1985年   2篇
  1984年   1篇
  1983年   1篇
  1982年   1篇
  1980年   1篇
  1977年   1篇
排序方式: 共有9322条查询结果,搜索用时 15 毫秒
31.
目的/意义随着人工智能时代的到来,在高校教学中进行学生学习动机激励机制的探索,寻找激励学生学习动力的课堂教学方法,有利于适应新时代大学教育改革,打造在线开放“金课”,助力高教质量提升。设计/方法基于互联网移动教学平台在本科课堂教学中实施翻转课堂,从ARCS四个维度设计课堂教学模式,构建四维融合学习动机理论视阈下移动平台翻转课堂教学效果影响因素模型,并利用结构方程模型进行实证分析。结论/发现基于ARCS理论设计的翻转课堂教学模式,能够对高校学生学习动机产生积极影响,提升教学满意度并改善教学效果。移动互联网与教育的深度融合,为高校实施“在线金课”教改提供更多的解决思路和实践探索,推动教育技术进步,增强教育活力和创新力。  相似文献   
32.
刘廷华 《北方论丛》2011,(2):148-152
情势变更原则作为一种分配意外风险的规则,可以节约与分配风险相关的交易成本。事实上,无论是理论基础、法律效果还是适用条件,情势变更规则无不具有令人信服的经济学逻辑,始终以提高资源配置效率为中心目标。  相似文献   
33.
风险社会的形成与大众媒介表征密不可分:大众媒介通过拟态环境的构建,形成了公众的风险感知,促成了风险传播的蝴蝶效应.在此基础上,探讨媒介形成社会风险的三方面成因:价值层面上,媒介的社会整合功能不足,价值培养欠缺;制度层面上,公益节目欠缺,政府信息制度贯彻不力;内容层面上:网络媒介的风险长尾效应日渐突出.  相似文献   
34.
In oncology, it may not always be possible to evaluate the efficacy of new medicines in placebo-controlled trials. Furthermore, while some newer, biologically targeted anti-cancer treatments may be expected to deliver therapeutic benefit in terms of better tolerability or improved symptom control, they may not always be expected to provide increased efficacy relative to existing therapies. This naturally leads to the use of active-control, non-inferiority trials to evaluate such treatments. In recent evaluations of anti-cancer treatments, the non-inferiority margin has often been defined in terms of demonstrating that at least 50% of the active control effect has been retained by the new drug using methods such as those described by Rothmann et al., Statistics in Medicine 2003; 22:239-264 and Wang and Hung Controlled Clinical Trials 2003; 24:147-155. However, this approach can lead to prohibitively large clinical trials and results in a tendency to dichotomize trial outcome as either 'success' or 'failure' and thus oversimplifies interpretation. With relatively modest modification, these methods can be used to define a stepwise approach to design and analysis. In the first design step, the trial is sized to show indirectly that the new drug would have beaten placebo; in the second analysis step, the probability that the new drug is superior to placebo is assessed and, if sufficiently high in the third and final step, the relative efficacy of the new drug to control is assessed on a continuum of effect retention via an 'effect retention likelihood plot'. This stepwise approach is likely to provide a more complete assessment of relative efficacy so that the value of new treatments can be better judged.  相似文献   
35.
One of the main advantages of factorial experiments is the information that they can offer on interactions. When there are many factors to be studied, some or all of this information is often sacrificed to keep the size of an experiment economically feasible. Two strategies for group screening are presented for a large number of factors, over two stages of experimentation, with particular emphasis on the detection of interactions. One approach estimates only main effects at the first stage (classical group screening), whereas the other new method (interaction group screening) estimates both main effects and key two-factor interactions at the first stage. Three criteria are used to guide the choice of screening technique, and also the size of the groups of factors for study in the first-stage experiment. The criteria seek to minimize the expected total number of observations in the experiment, the probability that the size of the experiment exceeds a prespecified target and the proportion of active individual factorial effects which are not detected. To implement these criteria, results are derived on the relationship between the grouped and individual factorial effects, and the probability distributions of the numbers of grouped factors whose main effects or interactions are declared active at the first stage. Examples are used to illustrate the methodology, and some issues and open questions for the practical implementation of the results are discussed.  相似文献   
36.
The aim of this paper is to describe a simulation procedure to compare parametric regression against a non-parametric regression method, for different functions and sets of information. The proposed methodology improves lack of fit at the edges of the regression curves, and an acceptable result is obtained for the no-parametric estimation in all studied cases. Larger differences appear at the edges of the estimation. The results are applied to the study of dasometric variables, which do not fulfil the normality hypothesis needed for parametric estimation. The kernel regression shows the relationship between the studied variables, which would not be detected with more rigid parametric models.  相似文献   
37.
The increasing use of family planning methods seems to be the intermediate determinant which mostly influences the fertility decline in developing countries, and in particular in those countries which are in an advanced phase of demographic transition such as Egypt. Moreover large countries, like Egypt, are characterized by very different geographical realities and even by strong regional heterogeneities. The aim of this study is the analysis of the determinants of contraceptive use in Egypt, with particular reference to the differentials due to the socio-economic context and to the area of residence. To estimate each individual and regional factors’ effect on contraceptive use, a logistic two-level random intercept model is fitted to EDHS 2000 data; the use of a multilevel analysis is suggested by the two-level data structure: the first level units are the women, the second level units are their regions of residence.  相似文献   
38.
In the estimators t 3 , t 4 , t 5 of Mukerjee, Rao & Vijayan (1987), b y x and b y z are partial regression coefficients of y on x and z , respectively, based on the smaller sample. With the above interpretation of b y x and b y z in t 3 , t 4 , t 5 , all the calculations in Mukerjee at al. (1987) are correct. In this connection, we also wish to make it explicit that b x z in t 5 is an ordinary and not a partial regression coefficient. The 'corrected' MSEs of t 3 , t 4 , t 5 , as given in Ahmed (1998 Section 3) are computed assuming that our b y x and b y z are ordinary and not partial regression coefficients. Indeed, we had no intention of giving estimators using the corresponding ordinary regression coefficients which would lead to estimators inferior to those given by Kiregyera (1984). We accept responsibility for any notational confusion created by us and express regret to readers who have been confused by our notation. Finally, in consideration of the above, it may be noted that Tripathi & Ahmed's (1995) estimator t 0 , quoted also in Ahmed (1998), is no better than t 5 of Mukerjee at al. (1987).  相似文献   
39.
运用菲德模型,以陕西省为例,测定教育部门对经济增长的全部作用和教育对经济中其他部门的外溢作用。结果表明,陕西省教育部门的边际生产力高于经济部门的边际生产力,但仍是相当的低。陕西省教育目前主要是通过外溢作用间接对经济发展发挥作用,其直接作用远远没有发挥出来,甚至表现为负的作用,教育部门的效率有待发挥。基于此,提出加大教育投入力度,深化教育部门内部改革,加快建设市场经济体制以充分发挥教育对经济的促进作用。  相似文献   
40.
针对水力发电企业的整体经济效益难以进行评价的问题,提出了以灰色关联度技术为支撑,选择数量模型评价方法,应用层次分析法的有关技术和思想,建立起具有可操作性的评价模型及评价体系。  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