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   31559篇
  免费   1442篇
  国内免费   248篇
管理学   1991篇
劳动科学   4篇
民族学   131篇
人才学   23篇
人口学   342篇
丛书文集   3196篇
理论方法论   564篇
综合类   20497篇
社会学   1007篇
统计学   5494篇
  2024年   25篇
  2023年   152篇
  2022年   245篇
  2021年   294篇
  2020年   438篇
  2019年   558篇
  2018年   635篇
  2017年   773篇
  2016年   723篇
  2015年   794篇
  2014年   1601篇
  2013年   2836篇
  2012年   2210篇
  2011年   2235篇
  2010年   1865篇
  2009年   1941篇
  2008年   2143篇
  2007年   2255篇
  2006年   2138篇
  2005年   1840篇
  2004年   1622篇
  2003年   1575篇
  2002年   1399篇
  2001年   1170篇
  2000年   574篇
  1999年   296篇
  1998年   164篇
  1997年   146篇
  1996年   118篇
  1995年   92篇
  1994年   63篇
  1993年   52篇
  1992年   39篇
  1991年   41篇
  1990年   25篇
  1989年   18篇
  1988年   19篇
  1987年   10篇
  1986年   7篇
  1985年   24篇
  1984年   19篇
  1983年   16篇
  1982年   19篇
  1981年   8篇
  1980年   7篇
  1979年   13篇
  1978年   10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 281 毫秒
31.
The case-cohort design is widely used as a means of reducing the cost in large cohort studies, especially when the disease rate is low and covariate measurements may be expensive, and has been discussed by many authors. In this paper, we discuss regression analysis of case-cohort studies that produce interval-censored failure time with dependent censoring, a situation for which there does not seem to exist an established approach. For inference, a sieve inverse probability weighting estimation procedure is developed with the use of Bernstein polynomials to approximate the unknown baseline cumulative hazard functions. The proposed estimators are shown to be consistent and the asymptotic normality of the resulting regression parameter estimators is established. A simulation study is conducted to assess the finite sample properties of the proposed approach and indicates that it works well in practical situations. The proposed method is applied to an HIV/AIDS case-cohort study that motivated this investigation.  相似文献   
32.
目前,网络视频实时在线评论激增带来的信息爆炸,使实时在线评论信息管理成为重要议题。以往对实时在线评论的研究多集中于个人行为结果方面,而缺乏对实时在线评论信息管理问题的关注;同时,现有视频网站对实时在线评论信息的管理也存在诸多局限。以爱奇艺视频网站热度榜中的电影为样本,基于信息质量维度框架并采用Tobit模型对实时在线评论用户认可度的影响因素进行研究,结果发现:实时在线评论的新颖性、相似性、情感倾向性和信息丰富性,均对实时在线评论的用户认可度存在显著影响,其中新颖性和相似性影响作用最大。视频网站可以据此进一步强化实时在线评论管理,改善用户的体验,保持用户的粘性。  相似文献   
33.
选取“一带一路”重点涉及的五大区域18个地区为研究对象,利用改进引力模型测量区域物流引力大小及地区引力总量,构建区域物流网络模型。在明确现有模型的特点和“一带一路”对物流网络目标要求的基础上,考虑区域物流发展水平和区域间差异情况,给出优化方案及优化后的物流网络模型,指出中国区域物流网络存在的问题并给出合理化建议,旨为政府决策提供参考。  相似文献   
34.
教师学术休假是促进教师专业发展的重要形式,是教师自我完善的需要,是提升教师理论水平、科研能力和教学技能的主要手段,是提高教学质量的有效途径。探讨地方高校推行学术休假制的必要性,提出地方高校推行学术休假的建议,对地方高校教师队伍建设具有重要的现实意义。在实施策略上,应注重4个方面:(1)明确参加学术休假的对象主要是教师和教学科研人员;(2)根据教师职业发展的阶段性确定学术休假的时间;(3)合理设置学术休假人员遴选条件,首先应考虑为工作满5年以上的青年教师提供学术休假,其次应考虑为高级职称教师提供学术休假;(4)明确学术休假期间的教师待遇,并加强对学术休假人员的管理。  相似文献   
35.
资本创造模型(CC模型)忽视了要素流动对产业空间分布的影响。而发展的新的资本创造模型则认为资本集聚的过程必然伴随着工业劳动力的流动过程。另外,是资本的实际收益而不是名义收益决定资本是否创造。研究结果表明,随着贸易自由度、工业品支出份额及资本贴现率的变大,替代弹性及资本折旧率的变小,将降低对称结构的稳定性,而提高中心-外围结构的稳定性;经济地理空间的产业均衡是集聚力和分散力相互作用的结果。当企业生产工业品的规模报酬递增程度足够显著,或者工业品支出份额很高时,市场拥挤效应将彻底消失,并转化成为促进产业集聚的动力;突破点与持续点的大小比较可以形成不同的关系,这意味着随着贸易自由度的变化,本文发展的资本创造模型可以体现出多样化的产业空间动态演化行为。  相似文献   
36.
部分线性模型是一类非常重要的半参数回归模型,由于它既含有参数部分又含有非参数部分,与常规的线性模型相比具有更强的适应性和解释能力。文章研究带有局部平稳协变量的固定效应部分线性面板数据模型的统计推断。首先提出一个两阶段估计方法得到模型中未知参数和非参数函数的估计,并证明估计量的渐近性质,然后运用不变原理构造出非参数函数的一致置信带,最后通过数值模拟研究和实例分析验证了该方法的有效性。  相似文献   
37.
BackgroundMidwife-led continuity of care has substantial benefits for women and infants and positive outcomes for midwives, yet access to these models remains limited. Caseload midwifery is associated with professional satisfaction and lower burnout, but also impacts on work-life boundaries. Few studies have explored caseload midwifery from the perspective of midwives working in caseload models compared to those in standard care models, understanding this is critical to sustainability and upscaling.AimTo compare views of caseload midwifery – those working in caseload models and those in standard care models in hospitals with and without caseload.MethodsA national cross-sectional survey of midwives working in Australian public hospitals providing birthing services.FindingsResponses were received from 542/3850 (14%) midwives from 111 hospitals – 20% worked in caseload, 39% worked in hospitals with caseload but did not work in the model, and 41% worked in hospitals without caseload. Regardless of exposure, midwives expressed support for caseload models, and for increased access to all women regardless of risk. Fifty percent of midwives not working in caseload expressed willingness to work in the model in the future. Flexibility, autonomy and building relationships were positive influencing factors, with on-call work the most common reason midwives did not want to work in caseload.ConclusionsThere was widespread support for and willingness to work in caseload. The findings suggest that the workforce could support increasing access to caseload models at existing and new caseload sites. Exposure to the model provides insight into understanding how the model works, which can positively or negatively influence midwives’ views.  相似文献   
38.
本文考虑一个供应商和两个独立零售商构成的供应链系统。当供应商的产能受到约束时,零售商可能会竞争有限的产能。本文提出将“优先分配权”作为一个有价值的标的物进行拍卖,按照出价高低确定优先分配顺序。本文证明了优先权拍卖机制属于共同价值模型,并提出了两类拍卖机制:事先拍卖和事后拍卖。本文证明两类优先权拍卖机制均会促使零售商提交真实的需求作为订单量,并且满足收益等价定理。而就供应商期望利润而言,事后优先权拍卖机制要高于事先优先权拍卖机制。  相似文献   
39.
In this article, an agent‐based framework to quantify the seismic resilience of an electric power supply system (EPSS) and the community it serves is presented. Within the framework, the loss and restoration of the EPSS power generation and delivery capacity and of the power demand from the served community are used to assess the electric power deficit during the damage absorption and recovery processes. Damage to the components of the EPSS and of the community‐built environment is evaluated using the seismic fragility functions. The restoration of the community electric power demand is evaluated using the seismic recovery functions. However, the postearthquake EPSS recovery process is modeled using an agent‐based model with two agents, the EPSS Operator and the Community Administrator. The resilience of the EPSS–community system is quantified using direct, EPSS‐related, societal, and community‐related indicators. Parametric studies are carried out to quantify the influence of different seismic hazard scenarios, agent characteristics, and power dispatch strategies on the EPSS–community seismic resilience. The use of the agent‐based modeling framework enabled a rational formulation of the postearthquake recovery phase and highlighted the interaction between the EPSS and the community in the recovery process not quantified in resilience models developed to date. Furthermore, it shows that the resilience of different community sectors can be enhanced by different power dispatch strategies. The proposed agent‐based EPSS–community system resilience quantification framework can be used to develop better community and infrastructure system risk governance policies.  相似文献   
40.
This article explores Myanmar teachers’ and community stakeholders’ constructions of disability. We examine how various religious perspectives – particularly Buddhism – inform and shape understandings of impairment and how these beliefs intersect with a strongly medicalised construction of disability. However, in our discussion and exploration of the responses, we also found that the notion of two primary disability ‘models’ – namely the medical model and the social model – lack nuance, complexity, and socio-cultural consideration. Through examining teachers’ and community members’ perspectives of disability in Myanmar, we highlight the importance of socio-cultural variance in understanding local constructions of disability.  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