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   95篇
  免费   6篇
管理学   12篇
民族学   1篇
人口学   9篇
理论方法论   7篇
综合类   1篇
社会学   53篇
统计学   18篇
  2021年   1篇
  2020年   3篇
  2019年   11篇
  2018年   4篇
  2017年   12篇
  2016年   7篇
  2015年   3篇
  2014年   5篇
  2013年   13篇
  2012年   6篇
  2011年   3篇
  2010年   2篇
  2009年   4篇
  2007年   4篇
  2006年   3篇
  2005年   1篇
  2004年   2篇
  2003年   1篇
  2002年   1篇
  1999年   1篇
  1998年   2篇
  1996年   2篇
  1995年   3篇
  1993年   1篇
  1991年   2篇
  1980年   1篇
  1978年   1篇
  1972年   1篇
  1968年   1篇
排序方式: 共有101条查询结果,搜索用时 562 毫秒
51.
Vacant and abandoned industrial buildings are a symptom of urban decline linked to various problems. To adopt effective regenerating policies, a full understanding of vacancy is required. This paper presents a study where the extent and condition of the vacant industrial buildings located in four Portuguese municipalities were assessed. Results showed that 613 buildings located in urban areas and in industrial parks, occupying an area of 1.4 million square meters, were vacant. The research is helpful for adopting regenerative policies and for understanding general questions of the characteristics of industrial vacancy and policies that are used to address this problem.  相似文献   
52.
The Bogotá River receives untreated wastewater from the city of Bogotá and many other towns. Downstream from Bogotá, water from the river is used for irrigation of crops. Concentrations of indicator organisms in the river are high, which is consistent with fecal contamination. To investigate the probability of illness due to exposure to enteric pathogens from the river, specifically Salmonella, we took water samples from the Bogotá River at six sampling locations in an area where untreated water from the river is used for irrigation of lettuce, broccoli, and cabbage. Salmonella concentrations were quantified by direct isolation and qPCR. Concentrations differed, depending on the quantification technique used, ranging between 107.7 and 109.9 number of copies of gene invA per L and 105.3 and 108.4 CFU/L, for qPCR and direct isolation, respectively. A quantitative microbial risk assessment model that estimates the daily risk of illness with Salmonella resulting from consuming raw unwashed vegetables irrigated with water from the Bogotá River was constructed using the Salmonella concentration data. The daily probability of illness from eating raw unwashed vegetables ranged between 0.62 and 0.85, 0.64 and 0.86, and 0.64 and 0.85 based on concentrations estimated by qPCR (0.47–0.85, 0.47–0.86, and 0.41–0.85 based on concentrations estimated by direct isolation) for lettuce, cabbage, and broccoli, respectively, which are all above the commonly propounded benchmark of 10?4 per year. Results obtained in this study highlight the necessity for appropriate wastewater treatment in the region, and emphasize the importance of postharvest practices, such as washing, disinfecting, and cooking.  相似文献   
53.
Force exertion is related to low back injuries (LBI). This paper critically reviews the literature concerning cut-points for back force exertion, presents available guidelines in a concise manner, and identifies areas that need further research. The studies reviewed were grouped according to the criteria used to set the cut-point values. Most often cut-points differ than concur. The approach considering physiological, psychophysical, epidemiological, and biomechanical aspects of back force exertion meets the most known criteria and presents the lowest common denominator of instantaneous load for lifting tasks. Further experimental and epidemiological studies in peak load and cumulative exposure are necessary. Compound indices should also be developed for pushing, pulling, and carrying. Future indices should consider electromyographically determined fatigue, differential viscoelastic properties of tissues, aging, and the cross sectional area of back muscles. We hope that this paper contributes to a more systematic appraisal of back force exertion at work.  相似文献   
54.
In this article, static light scattering (SLS) measurements are processed to estimate the particle size distribution of particle systems incorporating prior information obtained from an alternative experimental technique: scanning electron microscopy (SEM). For this purpose we propose two Bayesian schemes (one parametric and another non-parametric) to solve the stated light scattering problem and take advantage of the obtained results to summarize some features of the Bayesian approach within the context of inverse problems. The features presented in this article include the improvement of the results when some useful prior information from an alternative experiment is considered instead of a non-informative prior as it occurs in a deterministic maximum likelihood estimation. This improvement will be shown in terms of accuracy and precision in the corresponding results and also in terms of minimizing the effect of multiple minima by including significant information in the optimization. Both Bayesian schemes are implemented using Markov Chain Monte Carlo methods. They have been developed on the basis of the Metropolis–Hastings (MH) algorithm using Matlab® and are tested with the analysis of simulated and experimental examples of concentrated and semi-concentrated particles. In the simulated examples, SLS measurements were generated using a rigorous model, while the inversion stage was solved using an approximate model in both schemes and also using the rigorous model in the parametric scheme. Priors from SEM micrographs were also simulated and experimented, where the simulated ones were obtained using a Monte Carlo routine. In addition to the presentation of these features of the Bayesian approach, some other topics will be discussed, such as regularization and some implementation issues of the proposed schemes, among which we remark the selection of the parameters used in the MH algorithm.  相似文献   
55.
We undertake a comparative investigation of how neoliberal restructuring characterizes the third food regime in the three North American countries. By contrasting the experience of the two developed countries of the United States and Canada with that of the developing country of Mexico, we shine some empirical light on the differential impact of neoliberal regulatory restructuring on the division of labor in agriculture within the North American Free Trade Agreement region. In particular, we investigate these countries' agricultural production markets, trade, and food vulnerability—with an emphasis on Mexico—as analytical points for comparing and contrasting their experience with this neoliberal restructuring. We start with a synthesis of food‐regime theory and outline the key features of what we call the “neoliberal food regime.” We then discuss our case‐study countries in terms of food vulnerability and resistance in Mexico, their differential relationships to trade liberalization, and what these trends might mean for the evolution of the neoliberal food regime. We conclude that, while dominant trends are ominous, there is room for an alternative trajectory and consequent reshaping of the emerging regime: sufficient bottom‐up social resistance, primarily at the level of the nation–state, may yet produce an alternative trajectory.  相似文献   
56.
AStA Advances in Statistical Analysis - In the original paper, we incorrectly stated that...  相似文献   
57.
The Generalized gamma (GG) distribution plays an important role in statistical analysis. For this distribution, we derive non-informative priors using formal rules, such as Jeffreys prior, maximal data information prior and reference priors. We have shown that these most popular formal rules with natural ordering of parameters, lead to priors with improper posteriors. This problem is overcome by considering a prior averaging approach discussed in Berger et al. [Overall objective priors. Bayesian Analysis. 2015;10(1):189–221]. The obtained hybrid Jeffreys-reference prior is invariant under one-to-one transformations and yields a proper posterior distribution. We obtained good frequentist properties of the proposed prior using a detailed simulation study. Finally, an analysis of the maximum annual discharge of the river Rhine at Lobith is presented.  相似文献   
58.
Dichotomization of continuous variables to discriminate a dichotomous outcome is often useful in statistical applications. If a true threshold for a continuous variable exists, the challenge is identifying it. This paper examines common methods for dichotomization to identify which ones recover a true threshold. We provide mathematical and numeric proofs demonstrating that maximizing the odds ratio, Youden’s statistic, Gini Index, chi-square statistic, relative risk and kappa statistic all theoretically recover a true threshold. A simulation study evaluating the ability of these statistics to recover a threshold when sampling from a population indicates that maximizing the chi-square statistic and Gini Index have the smallest bias and variability when the probability of being larger than the threshold is small while maximizing Kappa or Youden’s statistics is best when this probability is larger. Maximizing odds ratio is the most variable and biased of the methods.  相似文献   
59.
Most family businesses employ more non-family employees than family employees, making them a crucial resource for family small-to-medium enterprises (SMEs). Thus, family SMEs must pay particular attention to developmental needs of such employees. However, there is limited empirical knowledge concerning how Family SMEs can manage and develop their non-family employees. Drawing on organizational justice theory, this study set out to investigate how and why non-family employees are satisfied with the High Involvement HR practices (HIHRPs) adopted by family SMEs. Empirical evidence was drawn from the experiences of 16 non-family employees from six SME family-owned enterprises. Findings suggest that a balance between formal and informal HIHRPs is need among family SMEs for non-family employees to be satisfied with them. Moreover, satisfaction with both formal and informal HIHRPs can encourage non-family employees’ engagement with the enterprise and the development of their skills and capabilities. Findings also suggest that the satisfaction with HIHRPs varies with respect to the organizational positioning of non-family employees. Our findings make a valuable and timely contribution to the human resource development and SME literatures in general.  相似文献   
60.
There exist an increasing number of studies that demonstrate the necessity to evaluate the processes which characterize a program and guarantee its implementation and evaluation. This paper deals with the implementation of a program designed to improve the acculturation of immigrant families in Spain (EU). Implementation followed a process that has proved successful in other settings, but is being applied here for the first time. Qualitative and quantitative measures are employed to assess each stage of implementation, with a particular emphasis on fidelity to program design. The intent was to guide effective revision of the program, and to establish it in a form that can be implemented on a larger scale.  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