全文获取类型
收费全文 | 118篇 |
免费 | 3篇 |
专业分类
管理学 | 26篇 |
民族学 | 2篇 |
人口学 | 9篇 |
丛书文集 | 1篇 |
理论方法论 | 3篇 |
综合类 | 1篇 |
社会学 | 54篇 |
统计学 | 25篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 1篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 8篇 |
2013年 | 8篇 |
2012年 | 16篇 |
2011年 | 8篇 |
2010年 | 7篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 2篇 |
2005年 | 1篇 |
2004年 | 2篇 |
2002年 | 3篇 |
2001年 | 1篇 |
1998年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
排序方式: 共有121条查询结果,搜索用时 0 毫秒
1.
Allard Denis Emery Xavier Lacaux Céline Lantuéjoul Christian 《Statistics and Computing》2020,30(5):1479-1495
Statistics and Computing - Two algorithms are proposed to simulate space-time Gaussian random fields with a covariance function belonging to an extended Gneiting class, the definition of which... 相似文献
2.
3.
Adrià López-Baucells Xavier Puig-Montserrat Ignasi Torre Lídia Freixas Maria Mas Antoni Arrizabalaga Carles Flaquer 《Urban Ecosystems》2017,20(1):217-225
Impact mitigation practices are currently one of the hottest topics in conservation and regarded as priorities worldwide. Forest bat populations are known to provide important ecosystem services such as pest control and bat boxes have become one of the most popular management options for counteracting the loss of roosts. However, bat boxes tend to be employed in non-native forests near highly humanized areas where human disturbance is higher. The aim of this study was to evaluate how the surrounding landscape composition affects bat box occupancy in urban non-native forests along the Mediterranean corridor in the Northeastern Iberian Peninsula. Two hundred wooden bat boxes were monitored in young non-native forests in the period 2004–2012. The influence of land cover on occupancy rate of bat boxes was analysed at the landscape level in a 5 km buffer around bat-box stations. In total, 1659 inspections were carried out, in which a 15 % occupancy rate was detected. Bat boxes hosted three different species (Pipistrellus pygmaeus, Pipistrellus kuhlii and Nyctalus leisleri). More than 70 % of the occupancy can be explained by habitat and spatial composition. The presence of urban areas around bat boxes tends to have a negative impact on bat occupation rates; by contrast, forest coverage has a positive effect, especially for the tree-dwelling bats. These patterns could be associated with the large number of available roosts in buildings, microhabitat or phylopatry. Thus, to increase success, we suggest that landscape composition should be considered when using bat boxes for conservation. 相似文献
4.
The two experimental methods most commonly used for reducing the effect of noise factors on a response of interest Y aim either to estimate a model of the variability (V(Y), or an associated function), that is transmitted by the noise factors, or to estimate a model of the ratio between the response (Y) and all the control and noise factors involved therein. Both methods aim to determine which control factor conditions minimise the noise factors' effect on the response of interest, and a series of analytical guidelines are established to reach this end. Product array designs allow robustness problems to be solved in both ways, but require a large number of experiments. Thus, practitioners tend to choose more economical designs that only allow them to model the surface response for Y. The general assumption is that both methods would lead to similar conclusions. In this article we present a case that utilises a design based on a product design and for which the conclusions yielded by the two analytical methods are quite different. This example casts doubt on the guidelines that experimental practice follows when using either of the two methods. Based on this example, we show the causes behind these discrepancies and we propose a number of guidelines to help researchers in the design and interpretation of robustness problems when using either of the two methods. 相似文献
5.
6.
Governments in Europe, Canada and the USA have expressed an ambition to stimulate education of older. In this paper, we analyse if there are effects on annual earnings of formal education for participants aged 42–55 at the time of enrolment in 1994–95. The analysis explores longitudinal population register data stretching from 1982 to 2007. The method used is difference‐in‐differences propensity score matching based on a rich set of covariates, including indicators of health and labor market marginalization. Our findings underline the importance of long follow up periods and imply positive effects for women, especially so for women with children, and no significant average earnings effects for men. These results differ from earlier studies but are stable to several alternative assumptions regarding unobservable characteristics. Data further indicate that the gender gap in our estimates may stem from differences in underlying reasons for enrolment. 相似文献
7.
In 1992, a package of measures was adopted by the city of Barcelona to obligate riders of motorcycles with a power capacity inferior to 125 cc to use helmets, until then only compulsory for larger motorcycles. Interrupted time series analyses with the use of a control group is used to investigate the effect of these measures on the number of serious injuries and number of deaths. The results indicate a significant decrease in the number of serious cases in the treated group—smaller motorcycles and mopeds—a decrease which does not occur in the control group —larger motorcycles. The impact of the adopted measures is abrupt and permanent but the change in riders helmet wearing habits has not been influenced so much by the media campaign as by the coming into force of the legislation with the potential application of sanctions. 相似文献
8.
9.
Xavier Gabaix 《Econometrica : journal of the Econometric Society》2011,79(3):733-772
This paper proposes that idiosyncratic firm‐level shocks can explain an important part of aggregate movements and provide a microfoundation for aggregate shocks. Existing research has focused on using aggregate shocks to explain business cycles, arguing that individual firm shocks average out in the aggregate. I show that this argument breaks down if the distribution of firm sizes is fat‐tailed, as documented empirically. The idiosyncratic movements of the largest 100 firms in the United States appear to explain about one‐third of variations in output growth. This “granular” hypothesis suggests new directions for macroeconomic research, in particular that macroeconomic questions can be clarified by looking at the behavior of large firms. This paper's ideas and analytical results may also be useful for thinking about the fluctuations of other economic aggregates, such as exports or the trade balance. 相似文献
10.
Xavier Vives 《Econometrica : journal of the Econometric Society》2011,79(6):1919-1966
A finite number of sellers (n) compete in schedules to supply an elastic demand. The cost of each seller is random, with common and private value components, and the seller receives a private signal about it. A Bayesian supply function equilibrium is characterized: The equilibrium is privately revealing and the incentives to rely on private signals are preserved. Supply functions are steeper with higher correlation among the cost parameters. For high (positive) correlation, supply functions are downward sloping, price is above the Cournot level, and as we approach the common value case, price tends to the collusive level. As correlation becomes maximally negative, we approach the competitive outcome. With positive correlation, private information coupled with strategic behavior induces additional distortionary market power above full information levels. Efficiency can be restored with appropriate subsidy schemes or with a precise enough public signal about the common value component. As the market grows large with the number of sellers, the equilibrium becomes price‐taking, bid shading is on the order of 1/n, and the order of magnitude of welfare losses is 1/n2. The results extend to inelastic demand, demand uncertainty, and demand schedule competition. A range of applications in product and financial markets is presented. 相似文献