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   92036篇
  免费   2952篇
  国内免费   4篇
管理学   11655篇
民族学   558篇
人才学   25篇
人口学   7386篇
丛书文集   538篇
教育普及   2篇
理论方法论   9591篇
现状及发展   1篇
综合类   2191篇
社会学   43994篇
统计学   19051篇
  2023年   519篇
  2021年   584篇
  2020年   1551篇
  2019年   2249篇
  2018年   2178篇
  2017年   3259篇
  2016年   2477篇
  2015年   2098篇
  2014年   2668篇
  2013年   19002篇
  2012年   2508篇
  2011年   2333篇
  2010年   2042篇
  2009年   2241篇
  2008年   2118篇
  2007年   1931篇
  2006年   2163篇
  2005年   2363篇
  2004年   2221篇
  2003年   1953篇
  2002年   2051篇
  2001年   2124篇
  2000年   1907篇
  1999年   1772篇
  1998年   1531篇
  1997年   1404篇
  1996年   1361篇
  1995年   1368篇
  1994年   1287篇
  1993年   1261篇
  1992年   1233篇
  1991年   1199篇
  1990年   1185篇
  1989年   1035篇
  1988年   1133篇
  1987年   997篇
  1986年   921篇
  1985年   1091篇
  1984年   1147篇
  1983年   1028篇
  1982年   935篇
  1981年   835篇
  1980年   809篇
  1979年   871篇
  1978年   738篇
  1977年   670篇
  1976年   605篇
  1975年   591篇
  1974年   485篇
  1973年   412篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
Social media is pervasive in the lives of young people, and this paper critically analyses how politically engaged young people integrate social media use into their existing organisations and political communications. This qualitative research project studied how young people from a broad range of existing political and civic groups use social media for sharing information, mobilisation and, increasingly, as a means to redefine political action and political spaces. Twelve in-person focus groups were conducted in Australia, the USA and the UK with matched affinity groups based on university campuses. The groups were of four types: party political group, issue-based group, identity-based group and social group. Our focus group findings suggest that this in-depth approach to understanding young people's political engagement reveals important group-based differences emerging in young people's citizenship norms: between the dutiful allegiance to formal politics and a more personalised, self-actualising preference for online, discursive forms of political engagement and organising. The ways in which political information is broadcast, shared and talked about on social media by engaged young people demonstrate the importance of communicative forms of action for the future of political engagement and connective action.  相似文献   
52.
ABSTRACT

The Flint Water Crisis became a national news story in January of 2016, when major publishers such as The New York Times began covering the story. In the same month, an influx of social media activism occurred in response to the crisis, with citizens developing hashtag campaigns such as #FlintFwd in order to disseminate news and stories from a citizen’s perspective; these campaigns often positioned Flint positively ? as a recovering community ? rather than a city in the middle of a public health crisis, and often addressed not a national public but a local audience. This paper considers Flint-based social media activity to investigate the emergence of place-based activism within the ostensibly global network of social media. In doing so, it identifies three key themes; 1) leveraging social media to forward a critique of deficient journalistic storytelling; 2) using the affective process of storytelling via social media to claim authority over their own material offline existence, and 3) using place-based storytelling to implicate others as witnesses via the global network of social media. These themes coalesce around a distinctly critical logic of connectivity. This logic extends the notion of connectivity articulated by Van Dijck and Poell [2013. Understanding social media logic. Media and Communication, 1(1), 2–14.] and the strategies of platform activism explored by Tufekci [2017. Twitter and tear gas: The power and fragility of networked protest. New Haven: Yale University Press.] to explain how social media works to expose discrepancies between the public story of the water crisis and material, lived conditions of Flint, rendering visible a discursive identity of Flint thus far unrecognized.  相似文献   
53.
Researchers have been developing various extensions and modified forms of the Weibull distribution to enhance its capability for modeling and fitting different data sets. In this note, we investigate the potential usefulness of the new modification to the standard Weibull distribution called odd Weibull distribution in income economic inequality studies. Some mathematical and statistical properties of this model are proposed. We obtain explicit expressions for the first incomplete moment, quantile function, Lorenz and Zenga curves and related inequality indices. In addition to the well-known stochastic order based on Lorenz curve, the stochastic order based on Zenga curve is considered. Since the new generalized Weibull distribution seems to be suitable to model wealth, financial, actuarial and especially income distributions, these findings are fundamental in the understanding of how parameter values are related to inequality. Also, the estimation of parameters by maximum likelihood and moment methods is discussed. Finally, this distribution has been fitted to United States and Austrian income data sets and has been found to fit remarkably well in compare with the other widely used income models.  相似文献   
54.
Urban Ecosystems - The development of urban areas imposes challenges that wildlife must adapt to in order to persist in these new habitats. One of the greatest changes brought by urbanization has...  相似文献   
55.
This paper proposes a new hysteretic vector autoregressive (HVAR) model in which the regime switching may be delayed when the hysteresis variable lies in a hysteresis zone. We integrate an adapted multivariate Student-t distribution from amending the scale mixtures of normal distributions. This HVAR model allows for a higher degree of flexibility in the degrees of freedom for each time series. We use the proposed model to test for a causal relationship between any two target time series. Using posterior odds ratios, we overcome the limitations of the classical approach to multiple testing. Both simulated and real examples herein help illustrate the suggested methods. We apply the proposed HVAR model to investigate the causal relationship between the quarterly growth rates of gross domestic product of United Kingdom and United States. Moreover, we check the pairwise lagged dependence of daily PM2.5 levels in three districts of Taipei.  相似文献   
56.
An accurate procedure is proposed to calculate approximate moments of progressive order statistics in the context of statistical inference for lifetime models. The study analyses the performance of power series expansion to approximate the moments for location and scale distributions with high precision and smaller deviations with respect to the exact values. A comparative analysis between exact and approximate methods is shown using some tables and figures. The different approximations are applied in two situations. First, we consider the problem of computing the large sample variance–covariance matrix of maximum likelihood estimators. We also use the approximations to obtain progressively censored sampling plans for log-normal distributed data. These problems illustrate that the presented procedure is highly useful to compute the moments with precision for numerous censoring patterns and, in many cases, is the only valid method because the exact calculation may not be applicable.  相似文献   
57.
ABSTRACT

The cost and time of pharmaceutical drug development continue to grow at rates that many say are unsustainable. These trends have enormous impact on what treatments get to patients, when they get them and how they are used. The statistical framework for supporting decisions in regulated clinical development of new medicines has followed a traditional path of frequentist methodology. Trials using hypothesis tests of “no treatment effect” are done routinely, and the p-value < 0.05 is often the determinant of what constitutes a “successful” trial. Many drugs fail in clinical development, adding to the cost of new medicines, and some evidence points blame at the deficiencies of the frequentist paradigm. An unknown number effective medicines may have been abandoned because trials were declared “unsuccessful” due to a p-value exceeding 0.05. Recently, the Bayesian paradigm has shown utility in the clinical drug development process for its probability-based inference. We argue for a Bayesian approach that employs data from other trials as a “prior” for Phase 3 trials so that synthesized evidence across trials can be utilized to compute probability statements that are valuable for understanding the magnitude of treatment effect. Such a Bayesian paradigm provides a promising framework for improving statistical inference and regulatory decision making.  相似文献   
58.
Bartlett correction constitutes one of the attractive features of empirical likelihood because it enables the construction of confidence regions for parameters with improved coverage probabilities. We study the Bartlett correction of spatial frequency domain empirical likelihood (SFDEL) based on general spectral estimating functions for regularly spaced spatial data. This general formulation can be applied to testing and estimation problems in spatial analysis, for example testing covariance isotropy, testing covariance separability as well as estimating the parameters of spatial covariance models. We show that the SFDEL is Bartlett correctable. In particular, the improvement in coverage accuracies of the Bartlett‐corrected confidence regions depends on the underlying spatial structures. The Canadian Journal of Statistics 47: 455–472; 2019 © 2019 Statistical Society of Canada  相似文献   
59.
The rise of the corporate profession has contributed to a more varied and ambiguous professional terrain that is increasingly seen to be indeterminate and fluid. This paper advances the current debate around the development of corporate professions, exploring how practitioners respond to this environment. Drawing on research with public relations practitioners, the paper shows how the idea of being a liminar facilitates the formation of a professional identity in conditions of high indeterminacy. In taking an individual level of analysis of professions, the paper suggests that indeterminacy is a more resonant feature for corporate professionals than previously suggested in the research, but that this indeterminacy is navigated in professional identity construction through ‘being a liminar’, and thus greater nuance may need to be recognized in the conceptualization of both corporate professions and corporate professionalization. It also demonstrates the use of liminality as a discursive resource in identity construction and with it, challenges the common association of liminality with self‐doubt and existential anxiety. In turn, the paper considers the implications of the liminal professional identity for the future of contemporary professions, and for understanding the liminal experience.  相似文献   
60.
Theory and Society - The massive expansion of US higher education after World War II is a sociological puzzle: a spectacular feat of state capacity-building in a highly federated polity. Prior...  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