全文获取类型
收费全文 | 17408篇 |
免费 | 719篇 |
国内免费 | 201篇 |
专业分类
管理学 | 1715篇 |
劳动科学 | 3篇 |
民族学 | 147篇 |
人才学 | 1篇 |
人口学 | 445篇 |
丛书文集 | 1200篇 |
理论方法论 | 618篇 |
综合类 | 9610篇 |
社会学 | 1656篇 |
统计学 | 2933篇 |
出版年
2024年 | 25篇 |
2023年 | 154篇 |
2022年 | 144篇 |
2021年 | 185篇 |
2020年 | 348篇 |
2019年 | 408篇 |
2018年 | 447篇 |
2017年 | 541篇 |
2016年 | 495篇 |
2015年 | 552篇 |
2014年 | 910篇 |
2013年 | 1787篇 |
2012年 | 1189篇 |
2011年 | 1169篇 |
2010年 | 942篇 |
2009年 | 930篇 |
2008年 | 1075篇 |
2007年 | 1158篇 |
2006年 | 1076篇 |
2005年 | 952篇 |
2004年 | 816篇 |
2003年 | 722篇 |
2002年 | 606篇 |
2001年 | 442篇 |
2000年 | 307篇 |
1999年 | 177篇 |
1998年 | 98篇 |
1997年 | 95篇 |
1996年 | 95篇 |
1995年 | 75篇 |
1994年 | 72篇 |
1993年 | 59篇 |
1992年 | 48篇 |
1991年 | 25篇 |
1990年 | 36篇 |
1989年 | 36篇 |
1988年 | 28篇 |
1987年 | 23篇 |
1986年 | 21篇 |
1985年 | 14篇 |
1984年 | 15篇 |
1983年 | 8篇 |
1982年 | 6篇 |
1981年 | 9篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2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 156 毫秒
11.
《Risk analysis》2018,38(8):1559-1575
Security of the systems is normally interdependent in such a way that security risks of one part affect other parts and threats spread through the vulnerable links in the network. So, the risks of the systems can be mitigated through investments in the security of interconnecting links. This article takes an innovative look at the problem of security investment of nodes on their vulnerable links in a given contagious network as a game‐theoretic model that can be applied to a variety of applications including information systems. In the proposed game model, each node computes its corresponding risk based on the value of its assets, vulnerabilities, and threats to determine the optimum level of security investments on its external links respecting its limited budget. Furthermore, direct and indirect nonlinear influences of a node's security investment on the risks of other nodes are considered. The existence and uniqueness of the game's Nash equilibrium in the proposed game are also proved. Further analysis of the model in a practical case revealed that taking advantage of the investment effects of other players, perfectly rational players (i.e., those who use the utility function of the proposed game model) make more cost‐effective decisions than selfish nonrational or semirational players. 相似文献
12.
AbstractIn general, survival data are time-to-event data, such as time to death, time to appearance of a tumor, or time to recurrence of a disease. Models for survival data have frequently been based on the proportional hazards model, proposed by Cox. The Cox model has intensive application in the field of social, medical, behavioral and public health sciences. In this paper we propose a more efficient sampling method of recruiting subjects for survival analysis. We propose using a Moving Extreme Ranked Set Sampling (MERSS) scheme with ranking based on an easy-to-evaluate baseline auxiliary variable known to be associated with survival time. This paper demonstrates that this approach provides a more powerful testing procedure as well as a more efficient estimate of hazard ratio than that based on simple random sampling (SRS). Theoretical derivation and simulation studies are provided. The Iowa 65+ Rural study data are used to illustrate the methods developed in this paper. 相似文献
13.
Keisuke Himoto 《Risk analysis》2020,40(6):1124-1138
Post-earthquake fires are high-consequence events with extensive damage potential. They are also low-frequency events, so their nature remains underinvestigated. One difficulty in modeling post-earthquake ignition probabilities is reducing the model uncertainty attributed to the scarce source data. The data scarcity problem has been resolved by pooling the data indiscriminately collected from multiple earthquakes. However, this approach neglects the inter-earthquake heterogeneity in the regional and seasonal characteristics, which is indispensable for risk assessment of future post-earthquake fires. Thus, the present study analyzes the post-earthquake ignition probabilities of five major earthquakes in Japan from 1995 to 2016 (1995 Kobe, 2003 Tokachi-oki, 2004 Niigata–Chuetsu, 2011 Tohoku, and 2016 Kumamoto earthquakes) by a hierarchical Bayesian approach. As the ignition causes of earthquakes share a certain commonality, common prior distributions were assigned to the parameters, and samples were drawn from the target posterior distribution of the parameters by a Markov chain Monte Carlo simulation. The results of the hierarchical model were comparatively analyzed with those of pooled and independent models. Although the pooled and hierarchical models were both robust in comparison with the independent model, the pooled model underestimated the ignition probabilities of earthquakes with few data samples. Among the tested models, the hierarchical model was least affected by the source-to-source variability in the data. The heterogeneity of post-earthquake ignitions with different regional and seasonal characteristics has long been desired in the modeling of post-earthquake ignition probabilities but has not been properly considered in the existing approaches. The presented hierarchical Bayesian approach provides a systematic and rational framework to effectively cope with this problem, which consequently enhances the statistical reliability and stability of estimating post-earthquake ignition probabilities. 相似文献
14.
The widely used empirical Bayes (EB) and full Bayes (FB) methods for before–after safety assessment are sometimes limited because of the extensive data needs from additional reference sites. To address this issue, this study proposes a novel before–after safety evaluation methodology based on survival analysis and longitudinal data as an alternative to the EB/FB method. A Bayesian survival analysis (SARE) model with a random effect term to address the unobserved heterogeneity across sites is developed. The proposed survival analysis method is validated through a simulation study before its application. Subsequently, the SARE model is developed in a case study to evaluate the safety effectiveness of a recent red‐light‐running photo enforcement program in New Jersey. As demonstrated in the simulation and the case study, the survival analysis can provide valid estimates using only data from treated sites, and thus its results will not be affected by the selection of defective or insufficient reference sites. In addition, the proposed approach can take into account the censored data generated due to the transition from the before period to the after period, which has not been previously explored in the literature. Using individual crashes as units of analysis, survival analysis can incorporate longitudinal covariates such as the traffic volume and weather variation, and thus can explicitly account for the potential temporal heterogeneity. 相似文献
15.
The socio-economic literature has focused much on how overall inequality in income distribution (frequently measured by the Gini coefficient) undermines the “trickle down” effect. In other words, the higher the inequality in the income distribution, the lower is the growth elasticity of poverty. However, with the publication of Piketty’s magnum opus (2014), and a subsequent study by Chancel and Piketty (2017) of evolution of income inequality in India since 1922, the focus has shifted to the income disparity between the richest 1% (or 0.01%) and the bottom 50%. Their central argument is that the rapid growth of income at the top end of millionaires and billionaires is a by-product of growth. The present study extends this argument by linking it to poverty indices in India. Based on the India Human Development Survey 2005–12 – a nationwide panel survey-we examine the links between poverty and income inequality, especially in the upper tail relative to the bottom 50%, state affluence (measured in per capita income) and their interaction or their joint effect. Another feature of our research is that we analyse their effects on the FGT class of poverty indices. The results are similar in as much as direction of association is concerned but the elasticities vary with the poverty index. The growth elasticities are negative and significant for all poverty indices. In all three cases, the disparity between the income share of the top 1% and share of the bottom 50% is associated with greater poverty. These elasticities are much higher than the (absolute) income elasticities except in the case of the poverty gap. The largest increase occurs in the poverty gap squared – a 1% greater income disparity is associated with a 1.24% higher value of this index. Thus the consequences of even a small increase in the income disparity are alarming for the poorest. 相似文献
16.
Increased juvenile delinquency can be seen as an indicator for a deteriorating social fabric under conditions of rapid social change. Criminological theories suggest, however, that such conditions do not per se produce delinquency: They force youth into prodelinquent leisure activities with peers, leading to an endorsement of delinquent behavior and offering the infrastructure for it. Resources acquired in family and public life, however, may prevent youth from drifting into such prodelinquent leisure activities and indirectly from delinquent behavior. Empirical tests of these hypotheses have to employ simultaneous analyses of societal-level and individual-level data. On the basis of an international youth study, the paper undertakes such an analysis: In the years 1992–95, data from 42 independent samples of seventh graders from East and West Germany, Poland, Russia, Bulgaria, Slovakia, Hungary, Czechia, and Greece were surveyed. Data on deviant school behavior, delinquent drift, nurturant parenting, and subjective feelings of justice in public were obtained from 7282 thirteen- to fourteen-year-olds. Processes of rapid social change were incorporated as data on changes in GNP in the years proceeding the surveys. Analyses show that delinquent drift is a valid predictor of deviant school behavior only on the individual level. The extent to which adolescents engage in prodelinquent peer activities depends more on the cultural context in which adolescents live than on their personal experience in the family and in public. Nurturant parenting does, however, covary negatively with deviant school behavior irrespective of level of analysis. 相似文献
17.
Sue Blackwell 《Journal of Sociolinguistics》2002,6(4):589-597
Book reviewed in this article:
Joan Dunayer, Animal Equality: Language and Liberation 相似文献
Joan Dunayer, Animal Equality: Language and Liberation 相似文献
18.
本论文主要讨论了基于WEB远程教学管理软件的分析与设计。首先对远程教育与传统教育进行了比较研究,确定远程教育是现代教育发展的方向;其次对开发基于WEB远程教学管理软件进行了环境分析和需求分析;最后讨论了远程教学管理软件的实现,包括软件模块结构设计和网站的总体框架。 相似文献
19.
文章介绍了近年来在美国、澳大利亚等国盛行的“体裁教学法”,评价了体裁和体裁分析理论,阐述了体裁分析的发展与特色,探讨了体裁分析法在商务语篇教学中的作用。 相似文献
20.
张文君 《西南科技大学学报(哲学社会科学版)》2002,19(1):51-54
讨论了地理信息系统GIS的路径分析算法 ,并在MAPGIS环境下 ,以西南科技大学道路网为例 ,利用VC 及MAPGIS二次开发类库实现了其最短路径和最佳路径分析。 相似文献