全文获取类型
收费全文 | 2692篇 |
免费 | 89篇 |
专业分类
管理学 | 335篇 |
民族学 | 39篇 |
人才学 | 1篇 |
人口学 | 343篇 |
丛书文集 | 2篇 |
理论方法论 | 219篇 |
综合类 | 51篇 |
社会学 | 1174篇 |
统计学 | 617篇 |
出版年
2024年 | 6篇 |
2023年 | 49篇 |
2022年 | 34篇 |
2021年 | 70篇 |
2020年 | 127篇 |
2019年 | 160篇 |
2018年 | 214篇 |
2017年 | 208篇 |
2016年 | 182篇 |
2015年 | 104篇 |
2014年 | 158篇 |
2013年 | 478篇 |
2012年 | 188篇 |
2011年 | 91篇 |
2010年 | 77篇 |
2009年 | 72篇 |
2008年 | 74篇 |
2007年 | 63篇 |
2006年 | 57篇 |
2005年 | 46篇 |
2004年 | 39篇 |
2003年 | 32篇 |
2002年 | 25篇 |
2001年 | 23篇 |
2000年 | 22篇 |
1999年 | 17篇 |
1998年 | 21篇 |
1997年 | 15篇 |
1996年 | 17篇 |
1995年 | 14篇 |
1994年 | 8篇 |
1993年 | 4篇 |
1992年 | 12篇 |
1991年 | 7篇 |
1990年 | 6篇 |
1989年 | 5篇 |
1988年 | 2篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 6篇 |
1984年 | 6篇 |
1983年 | 2篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1976年 | 2篇 |
1975年 | 3篇 |
1968年 | 5篇 |
1967年 | 1篇 |
排序方式: 共有2781条查询结果,搜索用时 10 毫秒
71.
We investigated the association between number of offspring and later-life mortality of Finnish men and women born 1938–50, and whether the association was explained by living conditions in own childhood and adulthood, chronic conditions, fertility timing, and unobserved characteristics common to siblings. We used a longitudinal 1950 census sample to estimate mortality at ages 50–72. Relative to parents of two children, all-cause mortality is highest among childless men and women, and elevated among those with one child, independently of observed confounders. Fixed-effect models, which control for unobserved characteristics shared by siblings, clearly support these findings among men. Cardiovascular mortality is higher among men with no, one, or at least four children than among those with two. Living conditions in adulthood contribute to the association between the number of children and mortality to a greater extent than childhood background, and chronic conditions contribute to the excess mortality of the childless. 相似文献
72.
Research examining impacts of teenage childbearing on economic and social outcomes have focused on completed schooling and labor force outcomes. In this paper, we examine outcomes that have remained largely unexplored, soft skills and personality. We use Add Health data to construct relevant controls for teenage mothers and explore a set of measures that proxy for what is usually deemed in economics as “non-cognitive” or “soft skill” traits. We find that teenage childbearing increases impulsivity, a trait that has been found to have negative effects on a large set of outcomes and has a negative effect on other personality traits perceived as positive, such as openness to experiences. Our results remain consistent through a set of robustness checks, and we interpret our findings to suggest that adolescence may be a sensitive period for the development of soft skills and that childbearing may interrupt this process. 相似文献
73.
74.
Unfortunately many of the numerous algorithms for computing the comulative distribution function (cdf) and noncentrality parameter
of the noncentral F and beta distributions can produce completely incorrect results as demonstrated in the paper by examples. Existing algorithms
are scrutinized and those parts that involve numerical difficulties are identified. As a result, a pseudo code is presented
in which all the known numerical problems are resolved. This pseudo code can be easily implemented in programming language
C or FORTRAN without understanding the complicated mathematical background.
Symbolic evaluation of a finite and closed formula is proposed to compute exact cdf values. This approach makes it possible
to check quickly and reliably the values returned by professional statistical packages over an extraordinarily wide parameter
range without any programming knowledge.
This research was motivated by the fact that a very useful table for calculating the size of detectable effects for ANOVA
tables contains suspect values in the region of large noncentrality parameter values compared to the values obtained by Patnaik’s
2-moment central-F approximation. The cause is identified and the corrected form of the table for ANOVA purposes is given. The accuracy of the
approximations to the noncentral-F distribution is also discussed.
The authors wish to thank Mr. Richárd Király for his preliminary work. The authors are grateful to the Editor and Associate
Editor of STCO and the unknown reviewers for their helpful suggestions. 相似文献
75.
Landscape urbanization threatens plant phylogenetic diversity in the Brazilian Atlantic Forest 总被引:1,自引:0,他引:1
Valdecir Silva-Junior Danielle G. Souza Rubens T. Queiroz Luiz G. R. Souza Elâine M. S. Ribeiro Bráulio A. Santos 《Urban Ecosystems》2018,21(4):625-634
Urbanization causes species loss around the world, but its effects on phylogenetic diversity are poorly known in tropical forests. Using a patch-landscape approach in an urbanizing region of the Brazilian Atlantic Forest, we tested whether the increase in landscape urbanization reduces plant species density, phylogenetic richness and divergence, and increases the relatedness among co-occurring individuals and species. We assessed plant responses to urbanization in adult (diameter at breast height?>?10 cm) and sapling communities (2.5–10 cm diameter) separately, as saplings are proxies of the future flora. We sampled 2860 woody plants belonging to 155 species in nine circular landscapes with urbanization level varying from 0% to 45%, and estimated the relatedness among the species that have increased and decreased in relative abundance in more urbanized landscapes (winner and losers, respectively). As expected, species density and phylogenetic richness decreased with the increase in urbanization. These responses were consistent for adult and sapling communities, suggesting a persistent loss of species and lineages in more urbanized landscapes. Contrary to our expectations, phylogenetic divergence and structure did not respond to urbanization, indicating that the more urbanized landscapes still retain much evolutionary history. However, because the relatedness among winners was greater than among losers, it is likely that the phylogenetic divergence gradually reduces and the relatedness increases, resulting in impoverished forests with uncertain ability to provide ecosystem services such as carbon storage and pest control. This environmental cost should be taken into account to align urban sprawl with biodiversity conservation. 相似文献
76.
Peter Chow-White Stephan Struve Alberto Lusoli Frederik Lesage Nilesh Saraf Amanda Oldring 《Information, Communication & Society》2018,21(3):448-464
Scholars, educators, regulators, pundits, and other observers are advocating for regulation and oversight of direct-to-consumer (DTC) genomic testing. As a result, the technology has been subject of highly visible public and regulatory controversy. In this article, we explore the nature and the shape of the sentiment of public discourse about the DTC company, 23andMe. We conduct a quantitative content analysis and qualitative framing analysis on Tweets. We find that the discourse surrounding DTC genomics and 23andMe is largely positive. We also identify a number of frames users deploy to debate, discuss, and share their experiences with DTC genomics and 23andMe. We argue that these frames create meaning around this emerging technology for its users. 相似文献
77.
Improving and measuring transparency in NGOs: A disclosure index for activities and projects 下载免费PDF全文
J. David Cabedo Iluminada Fuertes‐Fuertes Amparo Maset‐LLaudes José Miguel Tirado‐Beltrán 《Nonprofit management & leadership》2018,28(3):329-348
Nongovernmental organizations (NGOs) are established not with the aim of making profits but rather to provide social values by implementing different projects and activities. Transmitting complete information about these projects to society is a key element of transparency, as they operate within an atmosphere of public trust. Although there is a large body of literature on transparency in NGOs from a global perspective, very little research has been conducted on transparency within the area of projects and activities. This study takes a deeper look at this line and contributes to the literature on transparency in NGOs by proposing an index to measure the information transparency of the projects implemented by these organizations. The index captures three dimensions of the information about the projects (technical, financial, and scope) and makes it possible to: analyze the level of transparency of the portfolio of projects, detect the specific aspects that could be improved in each organization, and carry out comparisons among organizations. 相似文献
78.
Joaquín Castillo de Mesa María de las Olas Palma García Luis Gómez Jacinto 《European Journal of Social Work》2018,21(6):902-915
ABSTRACTSocial network services are allowing more social connectivity and making possible sharing information and knowledge of a different nature. This article analyses if social workers related to active social policies from Malaga province (Spain) are using social network services to share information and knowledge and if there is a mirror between online and offline relationships. Since it is an experimental model, through virtual ethnography and through social network analysis methodology, we observed the presence, connectivity and analysed the structure of relationships that keep 235 professionals from 52 organizations in Facebook®. Moreover, the model uses the statistical technique of modularity for detecting online communities, which are compared with distribution of professionals in their organizations. Results show how social network services applied to social intervention are massively and frequently used by professionals. On the other hand, the detected communities reflect existence of analogy between online and offline relationships. The online structure shows a high degree of cohesion and how certain professionals have higher capacity of influence and diffusion depending on position in the online structure. It argues about the opportunity to incorporate social network services towards social intervention as a manner of social innovation to improve cooperation and diffusion of information and knowledge. 相似文献
79.
Ríos-Chelén Alejandro Ariel Cuatianquiz-Lima Cecilia Bautista Amando Martínez-Gómez Margarita 《Urban Ecosystems》2018,21(1):15-25
Urban Ecosystems - Vermilion flycatchers, a suboscine, sing songs with more elements in territories with higher urban noise levels. We tested the hypothesis that this pattern is achieved through... 相似文献
80.
Urban Ecosystems - The global trend of increasing urbanization is generating isolated patches of vegetation that could be strongly influenced by the surrounding landscape. Simultaneously, many of... 相似文献