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   2748篇
  免费   178篇
  国内免费   28篇
管理学   182篇
劳动科学   2篇
民族学   13篇
人口学   91篇
丛书文集   176篇
理论方法论   59篇
综合类   1794篇
社会学   82篇
统计学   555篇
  2023年   21篇
  2022年   26篇
  2021年   30篇
  2020年   47篇
  2019年   53篇
  2018年   74篇
  2017年   90篇
  2016年   80篇
  2015年   104篇
  2014年   200篇
  2013年   265篇
  2012年   208篇
  2011年   240篇
  2010年   178篇
  2009年   133篇
  2008年   200篇
  2007年   205篇
  2006年   162篇
  2005年   131篇
  2004年   101篇
  2003年   110篇
  2002年   62篇
  2001年   67篇
  2000年   54篇
  1999年   20篇
  1998年   15篇
  1997年   13篇
  1996年   15篇
  1995年   16篇
  1994年   8篇
  1993年   9篇
  1992年   4篇
  1991年   5篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1977年   1篇
排序方式: 共有2954条查询结果,搜索用时 437 毫秒
1.
Objective: To compare anthropometric measures of body mass index (BMI), waist circumference (WC), waist-to-height ratio (WHtR), and sagittal abdominal diameter (SAD) as predictors of blood pressure in college students. Participants: Students (N = 116) were recruited from November 2012 to May 2014 at an urban university and rural community colleges. Methods: Students underwent a brief physical examination during which anthropometric measures were obtained and blood pressure was measured. Covariates were measured using self-reported questionnaires. Hierarchical multiple linear regressions were used for the data analysis. Results: All anthropometric measures were predictive of systolic (SBP) and diastolic blood pressure (DBP). WC was the strongest predictor of SBP (β = .582, p < .01) explaining an additional 3–4% of the variance than BMI, WHtR, or SAD. The measures were similar in predicting DBP. WC predicted SBP independent of BMI. Conclusions: Clinicians should consider using WC to assess the risk for hypertension in college students.  相似文献   
2.
李跃平  裴光兰 《民族学刊》2019,10(6):102-105, 143
《民族学刊》于2010年6月创刊,相继入选“复印报刊资料重要转载来源期刊”“北大核心期刊”“人文社科核心期刊”和“CSSCI来源期刊”,表明了《民族学刊》在学界和期刊界的学术影响,其期刊的影响因子值得研究和探讨。本文基于《中国学术期刊影响因子年报(人文社会科学)》公布的影响因子、各类计量指标和人文社科类影响因子、被引频次及可被引文献量等数据,对《民族学刊》的相应数据与C95民族学类期刊在期刊影响力指数、影响因子均值及量效指数均值、各类计量指标均值和人文社科类影响因子、被引频次及可被引文献量均值等方面进行统计对比,分析《民族学刊》2014~2018年五年间的影响因子数据在民族学类期刊位置及其学术影响。  相似文献   
3.
作为被广泛使用的社交媒体,微信已经成为热点事件和网络舆情的重要策源地,科学准确评估微信公众号的影响力对于明晰微信信息传播特点,深入挖掘微信传播潜力,进一步规范和指导微信平台的传播行为具有较大的理论和实践意义。在对既有关于微信公众号影响力研究进行梳理和评价的基础上,基于传播效果测量的设计,坚持以受众为中心、由浅入深多层次考察准则,运用德尔菲法和层次分析法建构一套微信公众号影响力指标体系。该指标体系由4个一级指标和9个二级指标构成,并运用线性合成法合成微信公众号影响力指数。  相似文献   
4.
随着信息技术的发展,数字经济已经成为经济增长的"新引擎"。但由于缺乏权威的产业统计分类标准,学者们一直面临"数字经济研究缺乏数字依据"的尴尬境地。文章基于国家统计局公布并实施的《数字经济及其核心产业统计分类(2021)》中的分类标准,对各省份统计年鉴的数据进行重新整理,利用熵权法构建数字经济发展指数,测度了我国30个省份的数字经济发展水平,分析了各省份数字经济发展的差异以及时空特征。研究发现,2009—2019年我国数字经济产业发展迅猛,各项子产业都取得了长足的进步。相比较而言,数字要素驱动业发展速度略低于其他三个子产业;数字经济发展存在着明显的区域不平衡。东中部地区的数字经济发展状况明显优于西部地区,南方优于北方,而且区域不平衡有持续扩大趋势。  相似文献   
5.
In a clinical trial, sometimes it is desirable to allocate as many patients as possible to the best treatment, in particular, when a trial for a rare disease may contain a considerable portion of the whole target population. The Gittins index rule is a powerful tool for sequentially allocating patients to the best treatment based on the responses of patients already treated. However, its application in clinical trials is limited due to technical complexity and lack of randomness. Thompson sampling is an appealing approach, since it makes a compromise between optimal treatment allocation and randomness with some desirable optimal properties in the machine learning context. However, in clinical trial settings, multiple simulation studies have shown disappointing results with Thompson samplers. We consider how to improve short-run performance of Thompson sampling and propose a novel acceleration approach. This approach can also be applied to situations when patients can only be allocated by batch and is very easy to implement without using complex algorithms. A simulation study showed that this approach could improve the performance of Thompson sampling in terms of average total response rate. An application to a redesign of a preference trial to maximize patient's satisfaction is also presented.  相似文献   
6.
7.
描述了标准供给的定义与测度,分析了要素禀赋结构对标准供给的作用机理,并对1993-2016年中国十六个制造业行业的面板数据进行了实证研究。研究结果表明:要素禀赋结构对标准供给有显着的正向影响,其中资本劳动比、研发资金投入、研发人力投入对标准供给的提升存在显著的正向影响,而且研发资金投入的影响最大,研发人力投入次之,资本劳动比的影响最小。这一结论对调整我国行业标准供给,提升我国标准市场竞争力具有重要意义。  相似文献   
8.
为评价重大工程团队免疫系统的健康和协调发展状况,本文提出了一种基于协调发展度的评价模型。首先通过文献查询和深度访谈,构建能够体现重大工程团队免疫系统特征的健康评价指标体系;其次利用改进的DEMATEL确定指标权重,然后采用多层次模糊综合评价将相关指标定量化,最终得出重大工程团队免疫系统的健康指数和协调发展度;再次确立重大工程团队免疫系统健康等级和协调发展度划分标准,同时提出免疫系统健康的跟踪评价策略;最后,利用本文模型对某跨国输气管道工程团队的免疫系统进行实证研究。结果表明,协调发展度模型既能反映重大工程团队免疫系统的整体健康程度,又能衡量固有性免疫和适应性免疫的协调发展状况,同时对免疫系统健康的跟踪评价也取得了良好效果。  相似文献   
9.
This article aims to conceptualize and assess social cohesion in Mexico, taking into account their multilevel and multidimensional nature. To measure social cohesion levels and dimensions, we used the Social Welfare Survey (N = 2871) for the 16 municipalities in Mexico City. Then, we employed the distance method to construct a social cohesion index. In addition, we define social cohesion degrees (very high, high, medium, and low) to explore the relevance of each indicator. The findings suggest that the objective and subjective indicators at the meso‐level has the highest contribution, regardless of the territory or degrees of cohesion. This finding suggests that neighborhoods are well organized for solving everyday problems. Meanwhile, the willingness to help both friends and members of one’s network was not a priority, which can be explained by the suspicion toward other people and the prevalent economic conditions.  相似文献   
10.
This study aims to calculate a scaled risk-taking behavior index and to test a model in which maternal and paternal parenting styles affect risk-taking behavior with a mediation of adolescents’ regulatory self-efficacy. Participants were 816 adolescents (44% males) responding to a self-report questionnaire about their risk-taking behavior, regulatory self-efficacy, and retrospective memories of paternal and maternal parenting styles. Results suggested an item rating in the index showing that behaviors considered less risky referred to alcohol use and the unplanned first sexual intercourse, whereas behaviors considered more risky referred to the lack of use of contraceptives and the age of the first sexual intercourse. Results revealed a significant indirect effect of authoritative and authoritarian styles on risk-taking behavior. These styles shaped the adolescents’ regulatory self-efficacy, which in turn predicted adolescent risk-taking behavior. Results underline the complex interplay of relationships between parents and their children.  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