全文获取类型
收费全文 | 1831篇 |
免费 | 63篇 |
国内免费 | 14篇 |
专业分类
管理学 | 111篇 |
民族学 | 15篇 |
人口学 | 24篇 |
丛书文集 | 152篇 |
理论方法论 | 53篇 |
综合类 | 1221篇 |
社会学 | 72篇 |
统计学 | 260篇 |
出版年
2024年 | 1篇 |
2023年 | 14篇 |
2022年 | 15篇 |
2021年 | 9篇 |
2020年 | 27篇 |
2019年 | 29篇 |
2018年 | 35篇 |
2017年 | 45篇 |
2016年 | 45篇 |
2015年 | 54篇 |
2014年 | 95篇 |
2013年 | 172篇 |
2012年 | 111篇 |
2011年 | 102篇 |
2010年 | 87篇 |
2009年 | 79篇 |
2008年 | 98篇 |
2007年 | 129篇 |
2006年 | 132篇 |
2005年 | 99篇 |
2004年 | 93篇 |
2003年 | 108篇 |
2002年 | 79篇 |
2001年 | 87篇 |
2000年 | 57篇 |
1999年 | 16篇 |
1998年 | 7篇 |
1997年 | 17篇 |
1996年 | 13篇 |
1995年 | 10篇 |
1994年 | 5篇 |
1993年 | 5篇 |
1992年 | 8篇 |
1991年 | 4篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
排序方式: 共有1908条查询结果,搜索用时 31 毫秒
51.
Ridhi Kashyap 《Population studies》2019,73(1):57-78
I examine whether prenatal sex selection has substituted postnatal excess female mortality by analysing the dynamics of child sex ratios between 1980 and 2015 using country-level life table data. I decompose changes in child sex ratios into a ‘fertility’ component attributable to prenatal sex selection and a ‘mortality’ component attributable to sex differentials in postnatal survival. Although reductions in numbers of excess female deaths have accompanied increases in missing female births in all countries experiencing the emergence of prenatal sex selection, relative excess female mortality has persisted in some countries but not others. In South Korea, Armenia, and Azerbaijan, mortality reductions favouring girls accompanied increases in prenatal sex selection. In India, excess female mortality was much higher and largely stable as prenatal sex selection emerged, but slight reductions were seen in the 2000s. In China, although absolute measures showed reductions, relative excess female mortality persisted as prenatal sex selection increased. 相似文献
52.
Using a real-world data set encompassing the daily portfolio holdings and exposures of complex investment funds, we derive a set of quantitative attributes to capture essential behavioral features of fund managers. We find the existence and stability of three investment attitudes, namely the conservative, the reactive, and the pro-active profiles, defining communities that respond differently when facing external shocks. The conservative community has behavioral similarities that tend to decrease due to external shocks, the reactive community members greatly increase their activity level especially during turmoil phases, while delegated investors in the pro-active community are more resilient to turbulence and counterbalance the impact of the events by adjusting their portfolio exposures in advance. We show that exogenous shocks only temporarily perturb the behavioral traits of the communities which then go back to their original states once the distress is embedded. 相似文献
53.
In this paper, we propose a model based on multivariate decomposition of multiplicative – absolute values and signs – components of asset returns. In the m-variate case, the marginals for the m absolute values and the binary marginals for the m directions are linked through a 2m-dimensional copula. The approach is detailed in the case of a bivariate decomposition. We outline the construction of the likelihood function and the computation of different conditional measures. The finite-sample properties of the maximum likelihood estimator are assessed by simulation. An application to predicting bond returns illustrates the usefulness of the proposed method. 相似文献
54.
Dafydd Evans 《统计学通讯:模拟与计算》2016,45(3):863-879
Given a noisy time series (or signal), one may wish to remove the noise from the observed series. Assuming that the noise-free series lies in some low-dimensional subspace of rank r, a common approach is to embed the noisy time series into a Hankel trajectory matrix. The singular value decomposition is then used to deconstruct the Hankel matrix into a sum of rank-one components. We wish to demonstrate that there may be some potential in using difference-based methods of the observed series in order to provide guidance regarding the separation of the noise from the signal, and to estimate the rank of the low-dimensional subspace in which the true signal is assumed to lie. 相似文献
55.
绿色低碳、节能减排已成为各国共识.竹这种绿色建材在现代建筑中的应用可展现建筑独特的风格,表达绿色环保的理念,在未来有广阔的发展前景.如何将竹这种具有中国独特韵味的南方建材引入北方是需要探讨的问题. 相似文献
56.
Diana Hernández Yang Jiang Daniel Carrión Douglas Phillips Yumiko Aratani 《Journal of Children and Poverty》2016,22(2):77-92
The costs for rent and utilities account for the largest share of living expenses, yet these two critical dimensions of material hardship have seldom been examined concurrently in population-based studies. This paper employs multivariate statistical analysis using American Community Survey data to demonstrate the relative risk ratio of low-income renter-occupied households with children experiencing ‘rent burden', ‘energy insecurity', or a ‘double burden’ as opposed to no burden. Findings suggest that low-income households are more likely to experience these economic hardships in general but that specific groups are disproportionately burdened in different ways. For instance, whereas immigrants are more likely to experience rental burden, they are less likely to experience energy insecurity and are also spared from the double burden. In contrast, native-born African Americans are more likely than all other groups to experience the double burden. These results may be driven by the housing stock available to certain groups due to racial residential segregation, decisions regarding the quality of housing low-income householders are able to afford, as well as home-country values, such as modest living and energy conservation practices, among immigrant families. This paper also points to important policy gaps in safety net benefits related to housing and energy targeting low-income households. 相似文献
57.
Antonello D'Ambra 《统计学通讯:理论与方法》2017,46(6):2942-2954
Taguchi's statistic has long been known to be a more appropriate measure of association of the dependence for ordinal variables compared to the Pearson chi-squared statistic. Therefore, there is some advantage in using Taguchi's statistic in the correspondence analysis context when a two-way contingency table consists at least of an ordinal categorical variable. The aim of this paper, considering the contingency table with two ordinal categorical variables, is to show a decomposition of Taguchi's index into linear, quadratic and higher-order components. This decomposition has been developed using Emerson's orthogonal polynomials. Moreover, two case studies to explain the methodology have been analyzed. 相似文献
58.
我国企业品牌定位的五层次研究 总被引:2,自引:0,他引:2
王庆 《沈阳农业大学学报(社会科学版)》2009,11(5):546-549
近年来中国企业的品牌建设取得了可喜的成绩,出现了许多优秀品牌,这些品牌凭借独特、合适的定位取得了成功。但企业在品牌定位方面存在许多误区,如把品牌定位看作产品定位、品牌定位模糊,缺乏差异性和明确的核心价值、品牌盲目延伸导致定位混淆等问题。因此,产品品牌定位必须树立正确的定位理念,应用正确的品牌定位方法。正确的品牌定位方法可分为产品特征定位、物质利益定位、情感利益定位、个性定位以及价值观定位共五个层次。 相似文献
59.
The performance of a tandem automated guided vehicle (AGV) system is compared with that of conventional AGV track systems. In the tandem system the track is divided into non-overlapping, single-vehicle closed loops. Using simulation it is shown that, because of trips requiring delivery across loops, the tandem system has a higher expected travel time per load and thus a greater average time in system. When the loads are delivered within the original loop only, the tandem system has a lower average time in system than in conventional systems, although the difference is modest. Track layout appears to influence the average time in system much more than docs the dispatching rule invoked. The success of the tandem system is highly dependent on approximately even AGV utilization, which may be difficult to obtain in practice. 相似文献
60.
陈婕 《淮海工学院学报(社会科学版)》2013,(8):123-125
介绍了广东省高职院校英语口语比赛的内容和方式,结合自身教学和指导比赛的实践,由此对现用教材、现有课程活动设置、学生的英语习惯思维以及师资引发了思考,在对先用教材和比赛用书进行比对的基础上,提出了相关对策建议。 相似文献