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   5572篇
  免费   198篇
  国内免费   59篇
管理学   628篇
劳动科学   2篇
民族学   37篇
人口学   60篇
丛书文集   305篇
理论方法论   106篇
综合类   2012篇
社会学   340篇
统计学   2339篇
  2024年   6篇
  2023年   48篇
  2022年   53篇
  2021年   45篇
  2020年   102篇
  2019年   130篇
  2018年   157篇
  2017年   242篇
  2016年   156篇
  2015年   145篇
  2014年   234篇
  2013年   807篇
  2012年   359篇
  2011年   255篇
  2010年   239篇
  2009年   232篇
  2008年   269篇
  2007年   310篇
  2006年   287篇
  2005年   306篇
  2004年   253篇
  2003年   256篇
  2002年   207篇
  2001年   182篇
  2000年   135篇
  1999年   75篇
  1998年   71篇
  1997年   50篇
  1996年   52篇
  1995年   30篇
  1994年   20篇
  1993年   19篇
  1992年   16篇
  1991年   12篇
  1990年   7篇
  1989年   12篇
  1988年   12篇
  1987年   7篇
  1986年   4篇
  1985年   6篇
  1984年   6篇
  1983年   2篇
  1982年   6篇
  1981年   3篇
  1979年   2篇
  1976年   1篇
  1975年   1篇
排序方式: 共有5829条查询结果,搜索用时 312 毫秒
1.
Longitudinal studies are the gold standard of empirical work and stress research whenever experiments are not plausible. Frequently, scales are used to assess risk factors and their consequences, and cross-lagged effects are estimated to determine possible risks. Methods to translate cross-lagged effects into risk ratios to facilitate risk assessment do not yet exist, which creates a divide between psychological and epidemiological work stress research. The aim of the present paper is to demonstrate how cross-lagged effects can be used to assess the risk ratio of different levels of psychosocial safety climate (PSC) in organisations, an important psychosocial risk for the development of depression. We used available longitudinal evidence from the Australian Workplace Barometer (N?=?1905) to estimate cross-lagged effects of PSC on depression. We applied continuous time modelling to obtain time-scalable cross effects. These were further investigated in a 4-year Monte Carlo simulation, which translated them into 4-year incident rates. Incident rates were determined by relying on clinically relevant 2-year periods of depression. We suggest a critical value of PSC?=?26 (corresponding to ?1.4 SD), which is indicative of more than 100% increased incidents of persistent depressive disorder in 4-year periods compared to average levels of PSC across 4 years.  相似文献   
2.
This article highlights three dimensions to understanding children's well‐being during and after parental imprisonment which have not been fully explored in current research. A consideration of ‘time’ reveals the importance of children's past experiences and their anticipated futures. A focus on ‘space’ highlights the impact of new or altered environmental dynamics. A study of ‘agency’ illuminates how children cope within structural, material and social confines which intensify vulnerability and dependency. This integrated perspective reveals important differences in individual children's experiences and commonalities in broader systemic and social constraints on prisoners’ children. The paper analyses data from a prospective longitudinal study of 35 prisoners’ children during and after their (step) father's imprisonment to illustrate the arguments.  相似文献   
3.
Participant retention is a key factor in determining the success of longitudinal research. Challenges in re-locating and retaining participants over the long term are major issues for researchers working with young people who face adversity and experience frequent changes in circumstances. This article reports on a study of vulnerable young people and their transition into adulthood. Rather than the more conventional schedule-based approach to locating and re-interviewing young people, a relational process, the ‘right time’ framework, was used to facilitate young people's involvement in the study. Embedded in the ‘right time’ framework is recognition of the diverse and fluctuating circumstances that shape young people's availability for interviews. Several case examples are considered which amplify the way that the ‘right time’ framework allowed the research to navigate around these circumstances. The case examples highlight the value young people attached to being involved in the research, the influence on the ‘right time’ of wider relational tensions for young people and the need to negotiate researcher status as a different sort of adult. The ‘right time’ framework contributed to a high retention rate in the study generating a more representative sample and enhancing the subsequent data analysis by providing valuable insights into the lives of these vulnerable young people.  相似文献   
4.
从现实出发,基于不同消费者导向类型研究了电商的全渠道决策问题。首先建立电商单渠道销售的基础模型,并得出最优产品组合、价格和交付时间。在此基础上,给出了消费者为产品导向型和渠道导向型情况下电商采取全渠道决策的条件,得出双渠道产品组合、价格及交付时间的最优决策;并进行了数值验证。研究发现,同一渠道提供的产品其最优价格相同,最优交付时间只和消费者耐心程度及交付成本函数有关。若消费者为产品导向型,仅当双渠道运营成本之差较小且消费者耐心程度较低时,电商进入线下渠道才有利可图,且在线下渠道提供最受欢迎的产品,线上渠道提供剩余产品。若消费者为渠道导向型,电商进入线下渠道必然有利可图,且在线下渠道提供最受欢迎的产品,线上渠道提供所有产品。  相似文献   
5.
Abstract

This article proposes a new approach to analyze multiple vector autoregressive (VAR) models that render us a newly constructed matrix autoregressive (MtAR) model based on a matrix-variate normal distribution with two covariance matrices. The MtAR is a generalization of VAR models where the two covariance matrices allow the extension of MtAR to a structural MtAR analysis. The proposed MtAR can also incorporate different lag orders across VAR systems that provide more flexibility to the model. The estimation results from a simulation study and an empirical study on macroeconomic application show favorable performance of our proposed models and method.  相似文献   
6.
给出了马尔可夫测度定义,讨论了马尔可夫测度的一部分性质  相似文献   
7.
A NOTE ON EVANESCENT PROCESSES   总被引:1,自引:0,他引:1  
This note examines the connection between μ-invariant measures for the transition function of a continuous-time Markov chain and those of its q-matrix, Q. The major result establishes a necessary and aufficient condition for a convergent μ-invariant measure for Q to be μ-inhant for the minimal transition function, P, under the assumption that P is honest. This corrects Theorem 6 of Vere-Jones (1969) and the first part of Corollary 1 of Pollett (1986), both of which assert that the above conclusion holds in the absence of this condition. The error was pointed out by E.A. van Doom (1991) and the counterexample which be presented provides the basis for the present arguments. In determining where the error occurred in the original proof, we are able to identify a simple sufficient condition for μ-invariance.  相似文献   
8.
语言作为文化的一部分,是文化的重要表达形式,透过一个民族的语言层面,可以窥见这个民族的文化形态。本文试图通过分析美国英语与时间有关的用语,来探讨美国人支配、利用时间的方式,以及时间这一无声的语言在美国文化中所蕴含的意义。  相似文献   
9.
由于英汉两种语言的差异,汉语中表因果关系的句子翻译成英文有不同的译法,除了采用原因状语从句的结构,还可以采用时间状语从句、地点状语从句、定语从句、不定式短语、介词短语、独立主格结构等多种不同的表达方式。  相似文献   
10.
SαS稳定分布是一类非常重要的非高斯随机分布,具有这类分布的噪声称为冲激噪声。在冲激噪声情况下,α阶以上的矩均不存在,导致基于二阶矩的高斯模型算法性能下降,甚至不能正常工作。该文提出了一种在冲激噪声环境下线性调频信号特征参数估计的算法,通过分析冲激噪声的具体特点,给出了修正的低阶矩模糊函数,并结合Radon变换估计了冲激噪声环境下LFM信号的参数。该算法既可应用于冲激噪声下,又可应用于高斯噪声环境,故具有较好的鲁棒性。最后用计算机仿真验证了该算法的有效性。  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