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   3046篇
  免费   123篇
  国内免费   23篇
管理学   234篇
民族学   12篇
人口学   76篇
丛书文集   270篇
理论方法论   158篇
综合类   1320篇
社会学   257篇
统计学   865篇
  2024年   2篇
  2023年   31篇
  2022年   26篇
  2021年   29篇
  2020年   69篇
  2019年   89篇
  2018年   94篇
  2017年   109篇
  2016年   83篇
  2015年   99篇
  2014年   150篇
  2013年   409篇
  2012年   180篇
  2011年   195篇
  2010年   169篇
  2009年   141篇
  2008年   167篇
  2007年   167篇
  2006年   148篇
  2005年   141篇
  2004年   149篇
  2003年   127篇
  2002年   101篇
  2001年   98篇
  2000年   66篇
  1999年   34篇
  1998年   23篇
  1997年   14篇
  1996年   22篇
  1995年   7篇
  1994年   7篇
  1993年   5篇
  1992年   6篇
  1991年   7篇
  1990年   4篇
  1989年   3篇
  1988年   7篇
  1986年   4篇
  1985年   4篇
  1984年   1篇
  1983年   5篇
排序方式: 共有3192条查询结果,搜索用时 187 毫秒
1.
建设具有中国特色、中国风格、中国气派的哲学社会科学,一直是我国哲学社会科学繁荣发展的根本目的.提升高校哲学社会科学繁荣发展水平,离不开科学有效的哲学社会科学研究评价.坚持党的领导、"二为"方向和"双百"方针是哲学社会科学繁荣发展的根本保障,坚持"质量为本"和"创新至上"是哲学社会科学繁荣发展的必然要求,坚持科学权威和公开透明是哲学社会科学研究评价的现实需要.结合当前高校哲学社会科学研究评价中"量化评价下数量与质量的关系论辩","学术评价与科研管理评价的边界异化"和"学术权力和行政权力的制度规制"三大问题聚讼,文章建议通过强化学术成果质量保障机制、优化学术共同体工作机制、构建学术争鸣长效机制和完善学术成果转化应用机制等制度建设,推动构建科学权威、公开透明的哲学社会科学研究评价体系,以期进一步改善新时代高校哲学社会科学研究评价工作.  相似文献   
2.
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   
3.
In studies with recurrent event endpoints, misspecified assumptions of event rates or dispersion can lead to underpowered trials or overexposure of patients. Specification of overdispersion is often a particular problem as it is usually not reported in clinical trial publications. Changing event rates over the years have been described for some diseases, adding to the uncertainty in planning. To mitigate the risks of inadequate sample sizes, internal pilot study designs have been proposed with a preference for blinded sample size reestimation procedures, as they generally do not affect the type I error rate and maintain trial integrity. Blinded sample size reestimation procedures are available for trials with recurrent events as endpoints. However, the variance in the reestimated sample size can be considerable in particular with early sample size reviews. Motivated by a randomized controlled trial in paediatric multiple sclerosis, a rare neurological condition in children, we apply the concept of blinded continuous monitoring of information, which is known to reduce the variance in the resulting sample size. Assuming negative binomial distributions for the counts of recurrent relapses, we derive information criteria and propose blinded continuous monitoring procedures. The operating characteristics of these are assessed in Monte Carlo trial simulations demonstrating favourable properties with regard to type I error rate, power, and stopping time, ie, sample size.  相似文献   
4.
Modeling spatial overdispersion requires point process models with finite‐dimensional distributions that are overdisperse relative to the Poisson distribution. Fitting such models usually heavily relies on the properties of stationarity, ergodicity, and orderliness. In addition, although processes based on negative binomial finite‐dimensional distributions have been widely considered, they typically fail to simultaneously satisfy the three required properties for fitting. Indeed, it has been conjectured by Diggle and Milne that no negative binomial model can satisfy all three properties. In light of this, we change perspective and construct a new process based on a different overdisperse count model, namely, the generalized Waring (GW) distribution. While comparably tractable and flexible to negative binomial processes, the GW process is shown to possess all required properties and additionally span the negative binomial and Poisson processes as limiting cases. In this sense, the GW process provides an approximate resolution to the conundrum highlighted by Diggle and Milne.  相似文献   
5.
Many research fields increasingly involve analyzing data of a complex structure. Models investigating the dependence of a response on a predictor have moved beyond the ordinary scalar-on-vector regression. We propose a regression model for a scalar response and a surface (or a bivariate function) predictor. The predictor has a random component and the regression model falls in the framework of linear random effects models. We estimate the model parameters via maximizing the log-likelihood with the ECME (Expectation/Conditional Maximization Either) algorithm. We use the approach to analyze a data set where the response is the neuroticism score and the predictor is the resting-state brain function image. In the simulations we tried, the approach has better performance than two other approaches, a functional principal component regression approach and a smooth scalar-on-image regression approach.  相似文献   
6.
For the unbalanced one-way random effects model with heterogeneous error variances, we propose the non-informative priors for the between-group variance and develop the first- and second-order matching priors. It turns out that the second-order matching priors do not exist and the reference prior and Jeffreys prior do not satisfy a first-order matching criterion. We also show that the first-order matching prior meets the frequentist target coverage probabilities much better than the Jeffreys prior and reference prior through simulation study, and the Bayesian credible intervals based on the matching prior and reference prior give shorter intervals than the existing confidence intervals by examples.  相似文献   
7.
Proportional hazards are a common assumption when designing confirmatory clinical trials in oncology. This assumption not only affects the analysis part but also the sample size calculation. The presence of delayed effects causes a change in the hazard ratio while the trial is ongoing since at the beginning we do not observe any difference between treatment arms, and after some unknown time point, the differences between treatment arms will start to appear. Hence, the proportional hazards assumption no longer holds, and both sample size calculation and analysis methods to be used should be reconsidered. The weighted log‐rank test allows a weighting for early, middle, and late differences through the Fleming and Harrington class of weights and is proven to be more efficient when the proportional hazards assumption does not hold. The Fleming and Harrington class of weights, along with the estimated delay, can be incorporated into the sample size calculation in order to maintain the desired power once the treatment arm differences start to appear. In this article, we explore the impact of delayed effects in group sequential and adaptive group sequential designs and make an empirical evaluation in terms of power and type‐I error rate of the of the weighted log‐rank test in a simulated scenario with fixed values of the Fleming and Harrington class of weights. We also give some practical recommendations regarding which methodology should be used in the presence of delayed effects depending on certain characteristics of the trial.  相似文献   
8.
We investigate the problem of estimating geodesic tortuosity and constrictivity as two structural characteristics of stationary random closed sets. They are of central importance for the analysis of effective transport properties in porous or composite materials. Loosely speaking, geodesic tortuosity measures the windedness of paths, whereas the notion of constrictivity captures the appearance of bottlenecks resulting from narrow passages within a given materials phase. We first provide mathematically precise definitions of these quantities and introduce appropriate estimators. Then, we show strong consistency of these estimators for unboundedly growing sampling windows. In order to apply our estimators to real data sets, the extent of edge effects needs to be controlled. This is illustrated using a model for a multiphase material that is incorporated in solid oxide fuel cells.  相似文献   
9.
Negative evaluative beliefs and other cognitive structures have been tied to psychological distress across various populations but have not been sufficiently incorporated into acculturation models. The current study examines the relationships between acculturation and various activating events and mediating sources of support related to negative evaluative beliefs among people of Mexican descent (N = 319). Overall, model variables explained 26% of the variance in negative evaluative beliefs. Acculturation, marital commitment, and social capital associated with friends were negatively related to negative evaluative beliefs. Conversely, single relationship status, marital reward value, psychosocial stressors, and bridging social capital were positively related, and likely serve as activating events for negative evaluative beliefs. Identifying mechanisms related to psychological distress as well as supportive structures may help in constructing interventions that will address the specific needs of different groups. Future research should continue to explore appraisal and associated beliefs in acculturation models to understand why acculturative experiences may become stressful.  相似文献   
10.
政治冲突的功能理论是政治冲突与整合理论的重要组成部分。由于目前对政治冲突与整合理论的研究非常少,所以作为它的重要组成部分的功能理论研究更为鲜见。本文在历史与逻辑相统一的理论框架下,结合前人的相关论述,特别是重点围绕马克思与L·科塞的观点,对政治冲突的功能:负功能和正功能进行了比较系统地分析。  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