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   23046篇
  免费   803篇
  国内免费   236篇
管理学   1920篇
劳动科学   4篇
民族学   301篇
人才学   1篇
人口学   620篇
丛书文集   1576篇
理论方法论   1679篇
综合类   12920篇
社会学   2356篇
统计学   2708篇
  2024年   44篇
  2023年   218篇
  2022年   244篇
  2021年   312篇
  2020年   510篇
  2019年   590篇
  2018年   613篇
  2017年   762篇
  2016年   678篇
  2015年   706篇
  2014年   1208篇
  2013年   2304篇
  2012年   1472篇
  2011年   1525篇
  2010年   1247篇
  2009年   1223篇
  2008年   1329篇
  2007年   1478篇
  2006年   1434篇
  2005年   1176篇
  2004年   1097篇
  2003年   1002篇
  2002年   834篇
  2001年   619篇
  2000年   426篇
  1999年   211篇
  1998年   109篇
  1997年   114篇
  1996年   106篇
  1995年   90篇
  1994年   69篇
  1993年   61篇
  1992年   47篇
  1991年   27篇
  1990年   31篇
  1989年   34篇
  1988年   26篇
  1987年   25篇
  1986年   22篇
  1985年   15篇
  1984年   16篇
  1983年   8篇
  1982年   8篇
  1981年   9篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1977年   1篇
  1975年   1篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
961.
The term “biodiversity” is often used to describe phenomena of nature, which can be studied without a reference to the socially constructed, evaluative, or indeed normative contexts. In our paper, we challenge this conception by focusing particularly on methodological aspects of biodiversity research. We thereby engage with the idea of interdisciplinary biodiversity research as a scientific approach directed at the recognition and management of contemporary society in its ecological embedding. By doing this, we explore how research on and assessments of biodiversity can be enhanced if meaning, aspiration, desires, and related aspects of agency are methodically taken into account. In six sections, we substantiate our claim that the discourse on biodiversity (including the IPBES (Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services) debate) is incomplete without contributions from the social sciences and humanities. In the introduction, a brief overview of biodiversity’s conceptual history is provided showing that “biodiversity” is a lexical invention intended to create a strong political momentum. However, that does not impede its usability as a research concept. Section 2 examines the origins of the Convention on Biological Diversity (CBD) by way of sociological discourse analysis. Subsequently, it proposes a matrix as a means to structure the ambiguities and tensions inherent in the CBD. The matrix reemphasizes our main thesis regarding the need to bring social and ethical expertise to the biodiversity discourse. In Section 3, we offer a brief sketch of the different methods of the natural and social sciences as well as ethics. This lays the groundwork for our Section 4, which explains and illustrates what social sciences and ethics can contribute to biodiversity research. Section 5 turns from research to politics and argues that biodiversity governance necessitates deliberative discourses in which participation of lay people plays an important role. Section 6 provides our conclusions.  相似文献   
962.
ABSTRACT

Despite both scholarly and popular claims that citizen journalism (CJ) represents a growing democratizing force in the journalistic field, recent scholarship in the area has noted the decline of the organizational population of CJ. In this paper, we investigate how individual characteristics of sites and the dynamics of larger organizational population affect a CJ site’s risk of experiencing a mortality. Drawing on the largest sample to date of US-based English-language CJ sites, this study examines the risk of site mortality through an event history framework. Findings indicate that the strongest predictor of a site’s mortality is the age of the site, consistent with organizational population theory’s ‘liability of newness.’ We also find that for-profit and community-based sites have lower rates of site mortality, indicating that adopting legitimate conventions of journalism may serve as a protective buffer to site death. The results offer mixed evidence on whether CJ has become more professionalized via attrition.  相似文献   
963.
This article intends to contribute to the increasing body of academic literature on the frontline delivery of activation policies. In line with the broader literature on frontline work, this literature focuses attention on frontline delivery practices and preferences and how these can be explained. Activation work is an interesting case in this context, because activation workers’ jobs designs vary considerably and workers have a diversity of educational backgrounds (including but not limited to social work) in the many countries that have implemented activation policies. This article looks at workers’ preferences rather than actual delivery practices. It analyses how job design and educational background are related to workers’ preferences concerning servicing clients, managing activation workers and spending time on various activation-related activities. Although the findings of the research that are presented in the article show that educational background and job design play only a modest role as antecedents of workers’ preferences, future research into this issue remains interesting. For it may help to increase our insights into the optimal match between what activation aims to achieve and how the provision of activation is organized on the one hand, and workers’ skills/qualifications and job design on the other hand.  相似文献   
964.
ABSTRACT

This article identifies trends in the adoption and implementation of quotas for corporate boards, an underresearched topic in political science. Corporate quotas—like legislative quotas—constitute the “fast track” to gender equality but appear more commonly in advanced democracies. These corporate quotas fall into three categories: laws covering all companies; laws covering state-owned companies only; and nonbinding (voluntary) measures in corporate governance codes. Despite on-paper differences, these corporate quotas are largely toothless. First generation corporate quotas, like first generation legislative quotas, operate symbolically. By raising the specter of stringent legislation in the long run, corporate quotas induce firms into voluntary compliance in the short run.  相似文献   
965.
In Portugal, there is a gap regarding psychological tests validated for forensic contexts, particularly those related to child custody issues. The Parent–Child Relationship Inventory (PCRI) is one of the most used instruments in child custody contexts. This study aimed to analyze the psychometric properties of PCRI in a Portuguese forensic sample. PCRI factorial structure and psychometric properties were analyzed in a sample of 144 parents involved in child custody assessments. The questionnaire showed good internal consistency, except for the parental support, autonomy, and role orientation scales. It also showed good discriminant capacity. The confirmatory factor analysis did not replicate the 7-factor model proposed by Gerard. The results were discussed based on the use of PCRI in the context of child custody assessment.  相似文献   
966.
We propose an adaptive functional autoregressive (AFAR) forecast model to predict electricity price curves. With time-varying operators, the AFAR model can be safely used in both stationary and nonstationary situations. A closed-form maximum likelihood (ML) estimator is derived under stationarity. The result is further extended for nonstationarity, where the time-dependent operators are adaptively estimated under local homogeneity. We provide theoretical results of the ML estimator and the adaptive estimator. Simulation study illustrates nice finite sample performance of the AFAR modeling. The AFAR model also exhibits a superior accuracy in the forecast exercise of the California electricity daily price curves compared to several alternatives.  相似文献   
967.
In drug development, it sometimes occurs that a new drug does not demonstrate effectiveness for the full study population but appears to be beneficial in a relevant subgroup. In case the subgroup of interest was not part of a confirmatory testing strategy, the inflation of the overall type I error is substantial and therefore such a subgroup analysis finding can only be seen as exploratory at best. To support such exploratory findings, an appropriate replication of the subgroup finding should be undertaken in a new trial. We should, however, be reasonably confident in the observed treatment effect size to be able to use this estimate in a replication trial in the subpopulation of interest. We were therefore interested in evaluating the bias of the estimate of the subgroup treatment effect, after selection based on significance for the subgroup in an overall “failed” trial. Different scenarios, involving continuous as well as dichotomous outcomes, were investigated via simulation studies. It is shown that the bias associated with subgroup findings in overall nonsignificant clinical trials is on average large and varies substantially across plausible scenarios. This renders the subgroup treatment estimate from the original trial of limited value to design the replication trial. An empirical Bayesian shrinkage method is suggested to minimize this overestimation. The proposed estimator appears to offer either a good or a conservative correction to the observed subgroup treatment effect hence provides a more reliable subgroup treatment effect estimate for adequate planning of future studies.  相似文献   
968.
The paper investigates various nonparametric models including regression, conditional distribution, conditional density and conditional hazard function, when the covariates are infinite dimensional. The main contribution is to prove uniform in bandwidth asymptotic results for kernel estimators of these functional operators. Then, the application issues, involving data-driven bandwidth selection, are discussed.  相似文献   
969.
Multiphase experiments are introduced and an overview of their design and analysis as it is currently practised is given via an account of their development since 1955 and a literature survey. Methods that are available for designing and analysing them are outlined, with an emphasis on making explicit the role of the model in their design. The availability of software and its use is described in detail. Overall, while multiphase designs have been applied in areas such as plant breeding, plant pathology, greenhouse experimentation, product storage, gene expression studies, and sensory evaluation, their deployment has been limited.  相似文献   
970.
We study a system of two non-identical and separate M/M/1/? queues with capacities (buffers) C1 < ∞ and C2 = ∞, respectively, served by a single server that alternates between the queues. The server’s switching policy is threshold-based, and, in contrast to other threshold models, is determined by the state of the queue that is not being served. That is, when neither queue is empty while the server attends Qi (i = 1, 2), the server switches to the other queue as soon as the latter reaches its threshold. When a served queue becomes empty we consider two switching scenarios: (i) Work-Conserving, and (ii) Non-Work-Conserving. We analyze the two scenarios using Matrix Geometric methods and obtain explicitly the rate matrix R, where its entries are given in terms of the roots of the determinants of two underlying matrices. Numerical examples are presented and extreme cases are investigated.  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