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   195篇
  免费   7篇
管理学   35篇
人口学   11篇
丛书文集   2篇
理论方法论   18篇
综合类   3篇
社会学   90篇
统计学   43篇
  2023年   4篇
  2020年   3篇
  2019年   7篇
  2018年   4篇
  2017年   6篇
  2016年   11篇
  2015年   2篇
  2014年   7篇
  2013年   29篇
  2012年   3篇
  2011年   2篇
  2010年   5篇
  2009年   5篇
  2008年   4篇
  2007年   14篇
  2006年   10篇
  2005年   8篇
  2004年   4篇
  2003年   6篇
  2002年   6篇
  2001年   2篇
  2000年   4篇
  1999年   3篇
  1998年   6篇
  1997年   2篇
  1996年   2篇
  1995年   3篇
  1994年   1篇
  1993年   5篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   3篇
  1988年   2篇
  1986年   2篇
  1985年   1篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   2篇
  1979年   1篇
  1978年   1篇
  1975年   2篇
  1973年   1篇
  1971年   1篇
  1970年   1篇
  1969年   1篇
  1968年   1篇
  1966年   1篇
  1963年   1篇
排序方式: 共有202条查询结果,搜索用时 15 毫秒
161.
This article critically examines the implications accompanying the introduction and implementation of recovery‐based policy. The article draws upon research conducted in Lancashire, England, where commissioners have been at the forefront of recent developments in ‘whole system’ models of commissioning. Empirical data are drawn on to make a series of new arguments about the tensions and practice implications of the new recovery agenda. The article has three main objectives. First, it explores current shifts in England, in which drug service commissioning has moved from being centrally funded and directed, to locally determined. Second, it references the rise of the well‐informed user in the reconfigured landscape of recovery and the ways in which commissioning models may enhance or negate the contribution of user activists to local cultures of recovery. Third, it references the changing political context, in which austerity is being used to increase the pressure on provider services to demonstrate social value, utility and effectiveness. The article argues that there is a palpable need to re‐politicize drug debates and recognize the structural and demographic factors which frame problem drug use, as well as the social and cultural factors which support or negate their opportunities for recovery.  相似文献   
162.

Background

Oxytocin is the most widely used drug in the induction of labor, but it could have potential adverse effects that derive from uterine hyperstimulation.

Aim

To determine the benefits and drawbacks of oxytocin continuation versus oxytocin discontinuation after the active phase of induced labor.

Methods

We systematically searched Pubmed, EMBASE, Scopus, ClinicalTrials.gov and Cochrane Library Plus until October 2017, for randomized controlled trials comparing oxytocin continuation with oxytocin discontinuation when the active phase of labor is reached were included. Data was collected by three reviewers and quality of the included studies assessed using the methodology recommended in the Cochrane Handbook. StatsDirect software was used to calculate risk ratios for binary variables and weighted mean differences for continuous variables. A fixed-effects or random-effects model was used as appropriate.

Results

Nine studies were selected including 1538 women, 774 in the oxytocin continuation group and 764 in the oxytocin discontinuation group. The incidence of cesarean sections (14.3% vs. 8.6%; relative risk, 1.67; 95% confidence interval: 1.25–2.23), uterine hyperstimulation (12.4% vs. 4.7%; relative risk, 2.59; 95% confidence interval: 1.70–3.93) and nonreassuring fetal heart rate (19.2% vs.12.5%; relative risk, 1.55; 95% confidence interval: 1.18–2.02) were significantly higher in the oxytocin continuation group. An increase in the duration of the second stage of labor in the oxytocin discontinuation group was observed (pooled mean difference, ?7.03; 95% confidence interval: ?9.80 to ?4.26).

Conclusions

After the active phase of induced labor, oxytocin continuation increases the risk of cesarean section, uterine hyperstimulation and alterations to the fetal heart rate.  相似文献   
163.
There is an emerging need to advance linear mixed model technology to include variable selection methods that can simultaneously choose and estimate important effects from a potentially large number of covariates. However, the complex nature of variable selection has made it difficult for it to be incorporated into mixed models. In this paper we extend the well known class of penalties and show that they can be integrated succinctly into a linear mixed model setting. Under mild conditions, the estimator obtained from this mixed model penalised likelihood is shown to be consistent and asymptotically normally distributed. A simulation study reveals that the extended family of penalties achieves varying degrees of estimator shrinkage depending on the value of one of its parameters. The simulation study also shows there is a link between the number of false positives detected and the number of true coefficients when using the same penalty. This new mixed model variable selection (MMVS) technology was applied to a complex wheat quality data set to determine significant quantitative trait loci (QTL).  相似文献   
164.
165.
In 2012, an art gallery in Birmingham, England presented an exhibition of ‘Children's Lives’. Through its curation of photography, fine art, objects, video and text, ‘Children's Lives’ claimed to ‘let childhood through the ages speak for itself’ and to contribute ‘to a debate over what it means to be a child’. In this article, we offer a critical analysis of the exhibition, examining the relationship between the exhibition as discourse and the ‘external’ discourses around childhood that are reinforced, negotiated and in some cases challenged by the assemblage of image, text and the spatial ‘narrative’ of the gallery.  相似文献   
166.
This paper is concerned with improving the performance of certain Markov chain algorithms for Monte Carlo simulation. We propose a new algorithm for simulating from multivariate Gaussian densities. This algorithm combines ideas from coupled Markov chain methods and from an existing algorithm based only on over-relaxation. The rate of convergence of the proposed and existing algorithms can be measured in terms of the square of the spectral radius of certain matrices. We present examples in which the proposed algorithm converges faster than the existing algorithm and the Gibbs sampler. We also derive an expression for the asymptotic variance of any linear combination of the variables simulated by the proposed algorithm. We outline how the proposed algorithm can be extended to non-Gaussian densities.  相似文献   
167.
Summary.  We consider maximum likelihood methods for estimating the end point of a distribution. The likelihood function is modified by a prior distribution that is imposed on the location parameter. The prior is explicit and meaningful, and has a general form that adapts itself to different settings. Results on convergence rates and limiting distributions are given. In particular, it is shown that the limiting distribution is non-normal in non-regular cases. Parametric bootstrap techniques are suggested for quantifying the accuracy of the estimator. We illustrate performance by applying the method to multiparameter Weibull and gamma distributions.  相似文献   
168.
利用计算机模拟技术和经验参数化方法,通过对镁铝尖晶石(MgAl2O4)晶体结构、晶格形成能及本征缺陷形成能的计算,论证了镁空位VMg^2-、氧空位Vo^2 和少量的AlMg^ 是MgAl2O4中的本征点缺陷.并指出其会以[VMg^2--Vo^2 ]空位对和[VMg^2--2lMg^ ]的形式实现电荷补偿.  相似文献   
169.
The proportion of adults with only wireless telephones is growingrapidly. Using 2006 data from the National Center for HealthStatistics’ National Health Interview Survey, this articleis among the first to reveal that noncoverage of this populationcan result in nonnegligible bias for traditional random-digit-diallandline telephone surveys that do not call wireless telephonenumbers. In 2006 in the United States, 17 percent of low-incomeadults with household income below 200 percent of the federalpoverty thresholds, 25 percent of young adults aged 18–29years, and 32 percent of low-income young adults lived in householdswith only wireless telephones. Within each of these three subgroups,we compared wireless-only adults and adults with landline telephoneson demographic characteristics and 13 key indicators of healthstatus, health behaviors, health care service use, and healthcare access. Even after statistical adjustments that accountfor demographic differences between adults living in householdswith and without landlines, telephone surveys of landlines willunderestimate the prevalence of health behaviors, such as bingedrinking, smoking, and HIV testing. Obesity may be overestimatedand physical activity may be underestimated for low-income youngadults. No significant bias is predicted for other measuresof health status and health insurance coverage. Sample weightingprocedures that incorporate adjustments for multiple demographiccharacteristics are necessary to help attenuate coverage biasin traditional telephone surveys, but may not be sufficientfor behavioral risk factor surveys of low-income and young adults.  相似文献   
170.
ABSTRACT

This study describes welfare-to-work participants in the San Francisco Bay Area, support services, experiences with the CalWORKs program, and predictors of employment status in the wake of welfare reform. Findings indicate that many are working and more Stayers and Recidivists than Leavers are using food stamps and Medi-Cal. Multivariate analysis reveals that race and financial supports were the significant factors contributing to employability, defined as the ability to secure employment despite the need to supplement earned income with welfare payments. To help people stay off of welfare, case management services are needed to help participants maintain employment and increase job skills. In addition to expanding our understanding of human behavior within the social environment of poverty, implications for practice and policy are identified.  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