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排序方式: 共有873条查询结果,搜索用时 15 毫秒
11.
我国高校当前新闻教育改革探究 总被引:1,自引:0,他引:1
从我国高校新闻教育的历史与现状入手,指出了当前国内高校新闻教育在学校教育、新闻实务界的反馈和学生与社会的态度三个方面反映出的问题,分析高校新闻教育改革的必要性与重要性,从树立大新闻传播教育观、新闻教育改革的具体实施、高校与媒体的互动等方面阐述改革的构想与措施。 相似文献
12.
基于SVM的Web日志挖掘及潜在客户发现 总被引:3,自引:1,他引:3
潜在的客户资源是商家未来的利润来源,发现了潜在的客户就可以制定相应的商业决策,并进行有针对性的客户关系管理。使用SVM方法对Web日志文件进行挖掘,以发现站点访问者中潜在客户的共同行为模式,并将其分为不同级别的目标客户群。同时,通过试验4种不同比例的训练样本,研究了非对称数据对分类结果的影响,以期获得较优的模型。 相似文献
13.
洗衣是日常生活中人们都要从事的一项家务劳动 ,主要操作者是女性。自古手洗衣服都要花费女人们较多的时间和精力。无论西方还是中国 ,传统的洗衣方式基本相同。自从洗衣机进入大部分家庭后 ,传统的手洗被机洗取代 ,妇女们有更多的时间从事自己喜欢的工作。 相似文献
14.
Dennis Wagenaar Tiaravanni Hermawan Marc J. C. van den Homberg Jeroen C. J. H. Aerts Heidi Kreibich Hans de Moel Laurens M. Bouwer 《Risk analysis》2021,41(1):37-55
Damage models for natural hazards are used for decision making on reducing and transferring risk. The damage estimates from these models depend on many variables and their complex sometimes nonlinear relationships with the damage. In recent years, data‐driven modeling techniques have been used to capture those relationships. The available data to build such models are often limited. Therefore, in practice it is usually necessary to transfer models to a different context. In this article, we show that this implies the samples used to build the model are often not fully representative for the situation where they need to be applied on, which leads to a “sample selection bias.” In this article, we enhance data‐driven damage models by applying methods, not previously applied to damage modeling, to correct for this bias before the machine learning (ML) models are trained. We demonstrate this with case studies on flooding in Europe, and typhoon wind damage in the Philippines. Two sample selection bias correction methods from the ML literature are applied and one of these methods is also adjusted to our problem. These three methods are combined with stochastic generation of synthetic damage data. We demonstrate that for both case studies, the sample selection bias correction techniques reduce model errors, especially for the mean bias error this reduction can be larger than 30%. The novel combination with stochastic data generation seems to enhance these techniques. This shows that sample selection bias correction methods are beneficial for damage model transfer. 相似文献
15.
Galateia Terti Isabelle Ruin Jonathan J. Gourley Pierre Kirstetter Zachary Flamig Juliette Blanchet Ami Arthur Sandrine Anquetin 《Risk analysis》2019,39(1):140-161
This article focuses on conceptual and methodological developments allowing the integration of physical and social dynamics leading to model forecasts of circumstance‐specific human losses during a flash flood. To reach this objective, a random forest classifier is applied to assess the likelihood of fatality occurrence for a given circumstance as a function of representative indicators. Here, vehicle‐related circumstance is chosen as the literature indicates that most fatalities from flash flooding fall in this category. A database of flash flood events, with and without human losses from 2001 to 2011 in the United States, is supplemented with other variables describing the storm event, the spatial distribution of the sensitive characteristics of the exposed population, and built environment at the county level. The catastrophic flash floods of May 2015 in the states of Texas and Oklahoma are used as a case study to map the dynamics of the estimated probabilistic human risk on a daily scale. The results indicate the importance of time‐ and space‐dependent human vulnerability and risk assessment for short‐fuse flood events. The need for more systematic human impact data collection is also highlighted to advance impact‐based predictive models for flash flood casualties using machine‐learning approaches in the future. 相似文献
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在《党的组织和党的出版物》一文中,列宁从基本自由、经济保障、价值取向和党性原则的角度对俄国报刊的发展路径进行了具体、系统的理论阐释,他认为要实现报刊发展就必须彻底摆脱警察压迫、摆脱资本、摆脱名位主义以及摆脱资产阶级无政府主义的个人主义。当下,回顾与反思列宁有关报刊发展的路径探析,可以得到3点启示:首先,要坚持正确的政治方向,为中国特色社会主义报刊事业提供根本保障;其次,要遵循“以人为本”,优化中国特色社会主义报刊事业的队伍建设;再次,要恪守党性原则,增强党对中国特色社会主义报刊事业的领导能力。 相似文献
19.
为减少热误差对数控机床加工精度的影响,文章利用灰色系统研究热误差建模。初步分析机床热源后,应用灰
色关联度分析结合模糊分类方法优化得到13组关键温度测点,结合小型精密五轴机床处于实际加工状态时的实验数
据,应用GM(I,N)灰色结构进行建模。将实际数据与拟合数据进行对比分析,结果表明此灰色系统模型具有计算方法
成熟、鲁棒性强的特点,适用于机床热误差研究。 相似文献
20.
ABSTRACTWe describe two recently proposed machine learning approaches for discovering emerging trends in fatal accidental drug overdoses. The Gaussian Process Subset Scan (Herlands, McFowland, Wilson, & Neill, 2017) enables early detection of emerging patterns in spatio-temporal data, accounting for both the complex, correlated nature of the data and the fact that detecting subtle patterns requires integration of information across multiple spatial areas and multiple time steps. We apply this approach to 17 years of county-aggregated data for monthly opioid overdose deaths in the New York City metropolitan area, showing clear advantages in the utility of discovered patterns as compared to typical anomaly detection approaches. To detect and characterize emerging overdose patterns that differentially affect a subpopulation of the data, including geographic, demographic, and behavioral patterns (e.g., which combinations of drugs are involved), we apply the Multidimensional Tensor Scan (Neill, 2017) to 8 years of case-level overdose data from Allegheny County, Pennsylvania. We discover previously unidentified overdose patterns which reveal unusual demographic clusters, show impacts of drug legislation, and demonstrate potential for early detection and targeted intervention. These approaches to early detection of overdose patterns can inform prevention and response efforts, as well as understanding the effects of policy changes. 相似文献