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   982篇
  免费   28篇
  国内免费   35篇
管理学   109篇
劳动科学   1篇
民族学   9篇
人口学   34篇
丛书文集   45篇
理论方法论   55篇
综合类   485篇
社会学   172篇
统计学   135篇
  2023年   4篇
  2022年   9篇
  2021年   17篇
  2020年   23篇
  2019年   41篇
  2018年   23篇
  2017年   50篇
  2016年   37篇
  2015年   29篇
  2014年   72篇
  2013年   152篇
  2012年   50篇
  2011年   46篇
  2010年   43篇
  2009年   49篇
  2008年   51篇
  2007年   49篇
  2006年   44篇
  2005年   35篇
  2004年   25篇
  2003年   34篇
  2002年   21篇
  2001年   27篇
  2000年   18篇
  1999年   17篇
  1998年   11篇
  1997年   12篇
  1996年   12篇
  1995年   10篇
  1994年   7篇
  1993年   10篇
  1992年   4篇
  1991年   3篇
  1990年   2篇
  1989年   3篇
  1987年   2篇
  1986年   1篇
  1983年   1篇
  1982年   1篇
排序方式: 共有1045条查询结果,搜索用时 78 毫秒
1.
Citizen Review Panels (CRPs) are groups of citizen volunteers authorized by U.S. federal law to examine state child welfare agencies. These groups inspect policies and practices related to child protection responsibilities and are tasked with making recommendations for systemic improvement. Despite the federal mandate for each state to develop a CRP and the potential of these groups to positively impact child welfare practices, there is a dearth in the literature related to CRPs. Consequently, planning and evaluation processes of these groups vary widely. This study reports on the use of concept mapping (CM) to outline a framework for planning and subsequently evaluating the CRP in one southeastern state. CM is a mixed-method research approach that uses multi-dimensional scaling and hierarchical cluster analyses to explore an area of study. Through these analyses, the method creates visual depictions of conceptual relationships between ideas. Data yielded a seven cluster concept map that CRP members (N = 36) utilized for planning processes, and subsequently for developing an internal evaluation tool. Results from this study offer a unifying framework by which CRPs, and similar groups in other areas can utilize for planning and evaluation purposes. After a review of pertinent literature on CRPs, this article explicates CM processes utilized in this study, describes results, discusses lessons learned, and outlines apposite areas for future CRP research.  相似文献   
2.
基于认知隐喻理论,选择德语中14个表征空间性状的形容词,探究其时间映射特质。研究发现:长/短、大/小、远/近、高、深可表征时间,其余则无法表征时间。具体特质如下:存在“一维>二维>三维”映射维度等级;存在“长短>远近>高深/大小”映射宽幅等级;正向形容词比负向更易表征时间。这种映射特质主要与时空相似性、认知思维及隐喻操作有关。  相似文献   
3.
根据社会形势对人才提出的新要求,结合大学生的身心特点和心理现状,高校的心理健康教育,应着力于心理健康知识、心理调适方法和心理疾病的防治等方面。  相似文献   
4.
在实一致光滑Banach空间中引入了一类新的逼近三个极值强伪压缩映象唯一公共不动点的带误差迭代序列,以及通过Petryshyn不等式讨论了该带误差迭代序列的收敛性.  相似文献   
5.
关系数据模型是基于记录的基本数据模型;面向对象数据模型是基于对象的基本数据模型;两种数据模型在某种程度上应存在相互映射和相互转变的可能性,它们的相互映射和相互转变将使关系数据库和面向对象数据库之间的转变成为可能。  相似文献   
6.
Informal caregivers of individuals with Alzheimer's disease spend a considerable amount of time providing care. In this paper, we use Grossman's health production and Becker's time allocation models to develop a model of informal care provision to elderly dementia patients. In our model, time inputs produce caregiving services, which provides utility to the caregiver, but reduces leisure. We assume that time is less productive of services on the margin as the disease progresses. In this framework, an increase in patients' disease severity does not necessarily increase informal caregiver time input. The cost of formal care establishes a reservation price for informal caregiving. When the costs of informal caregiving rise above this reservation level, the patient is institutionalized. We test empirically the effect of deterioration in the patients' condition, proxied by both disease severity and dementia problem behavior, on informal caregiving time. We find that dementia-related problem behaviors and functional limitations significantly increase inputs of informal caregiving time. Patients' problem behavior exerts a modifying effect on functional limitations, and patients' comorbidities have no effect on informal caregiving time.  相似文献   
7.
分析了厚电极厚缓冲层的共面波导Mach-Zehnder行波电极LiNbO3光调制器,讨论了电极厚度和缓冲层厚度对调制器特性参数的影响,得到了调制器的有效折射率、特征阻抗、半波电压及损耗系数等参数。通过对比分析,选择合适的电极厚度和缓冲层厚度,优化调制器性能,近似满足速度和阻抗匹配,实现了图宽带调制。  相似文献   
8.
On Block Updating in Markov Random Field Models for Disease Mapping   总被引:3,自引:0,他引:3  
Gaussian Markov random field (GMRF) models are commonly used to model spatial correlation in disease mapping applications. For Bayesian inference by MCMC, so far mainly single-site updating algorithms have been considered. However, convergence and mixing properties of such algorithms can be extremely poor due to strong dependencies of parameters in the posterior distribution. In this paper, we propose various block sampling algorithms in order to improve the MCMC performance. The methodology is rather general, allows for non-standard full conditionals, and can be applied in a modular fashion in a large number of different scenarios. For illustration we consider three different applications: two formulations for spatial modelling of a single disease (with and without additional unstructured parameters respectively), and one formulation for the joint analysis of two diseases. The results indicate that the largest benefits are obtained if parameters and the corresponding hyperparameter are updated jointly in one large block. Implementation of such block algorithms is relatively easy using methods for fast sampling of Gaussian Markov random fields ( Rue, 2001 ). By comparison, Monte Carlo estimates based on single-site updating can be rather misleading, even for very long runs. Our results may have wider relevance for efficient MCMC simulation in hierarchical models with Markov random field components.  相似文献   
9.
用台湾爆发口蹄疫的案例实证演绎了生猪传染性疫病对猪肉贸易的重大影响。研究认为:疫病预防和控制以及国际认可、国家兽医体制的控制能力以及生猪适度规模饲养是猪肉贸易健康发展的关键因素,因此,作为养猪大国的中国,必须吸取国际经验,完善生猪疫病预防和控制,促进猪肉贸易发展。  相似文献   
10.
Foot and mouth disease (FMD) is considered by many as the most important animal disease in the world. FMD is highly contagious and outbreaks incur significant costs as affected countries are severely limited in their ability to trade. A number of trade commodities may be contaminated with FMD virus (FMDV) including animal products, for example, meat. As a member of the European Union, Great Britain (GB) has put in place a number of regulations to prevent the importation of pathogens in imported meat products. However, the illegal importation of meat provides a route by which safety controls may be circumvented and meat from FMD affected areas may be imported. This study assesses the FMD infection risk posed to the livestock population of GB from the illegal importation of meat, and estimates the major contributors to this overall risk, through the development of a quantitative risk assessment model. From model results, the total amount of illegal meat entering GB each year is estimated on average to be 11,875 tonnes. with 90% certainty that this is between 4,398 and 28,626 tonnes per year; of which between 64.5 and 565 kg are contaminated with FMDV. This flow of illegal meat results in an estimate of a frequency of FMD infection in GB livestock of 0.015 cases of infected animals per year, with 90% certainty it is between 0.0017 and 0.053. Imports from the region Near and Middle East account for 47% of this risk, and 68% of the risk is attributed to bone-in and dried de-boned products.  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