全文获取类型
收费全文 | 508篇 |
免费 | 24篇 |
专业分类
管理学 | 56篇 |
民族学 | 4篇 |
人才学 | 1篇 |
人口学 | 40篇 |
丛书文集 | 2篇 |
理论方法论 | 64篇 |
综合类 | 2篇 |
社会学 | 306篇 |
统计学 | 57篇 |
出版年
2024年 | 1篇 |
2023年 | 8篇 |
2022年 | 8篇 |
2021年 | 7篇 |
2020年 | 16篇 |
2019年 | 22篇 |
2018年 | 27篇 |
2017年 | 27篇 |
2016年 | 31篇 |
2015年 | 28篇 |
2014年 | 28篇 |
2013年 | 99篇 |
2012年 | 26篇 |
2011年 | 31篇 |
2010年 | 15篇 |
2009年 | 21篇 |
2008年 | 19篇 |
2007年 | 14篇 |
2006年 | 14篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 8篇 |
2000年 | 7篇 |
1999年 | 2篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 4篇 |
1991年 | 5篇 |
1990年 | 2篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 3篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1978年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有532条查询结果,搜索用时 15 毫秒
471.
Whitney Carroll Joel W. Snodgrass Katalin Szlavecz Edward R. Landa Ryan E. Casey Steven M. Lev 《Urban Ecosystems》2014,17(3):825-838
Increased urban development, including an increase in impervious surfaces has the potential to alter the biogeochemistry of surface systems due to storm water runoff contaminated with potentially toxic trace metals (e.g. Zn, Cu and Pb). A major source for urban metals is dust that accumulates on roadways. This roadway dust is derived from vehicle wear sources and tends to be enriched in trace metals such as Pb, Zn, Cu, Cd, Ni and Cr. This continuous source is then being transported via storm water runoff to receiving systems, such as storm water retention systems, which become important focusing environments for trace metal deposition. The fate of these roadway derived metals and their bioavailability once deposited in these urban ecosystems is not well understood. In this investigation we tested the hypothesis that the distribution and form of surface deposited roadway-derived Zn is a function of earthworm processes and is species dependent. The results of this investigation indicate that roadway dust derived Zn deposited as a surface layer on urban soils is readily removed from the surface in less than 30 days whether earthworms are present or not. However, after 90 days, the presence of earthworms and the life habit of the earthworm species present was found to have a significant impact on the physical and chemical cycling of roadway derived trace metals in storm water retention basin soils. 相似文献
472.
473.
474.
Sheila Ryan Johansson 《Population studies》2013,67(3):527-534
It is generally agreed that the marital instability and casual mating characteristic of West Indian family structure depress fertility. These conditions are traced to the mating organization of the slaves. The stresses placed on the Mrican family systems of the slaves are obvious: the continued importation of slaves, most of them young adult males; the ruthless separation of kin through sale or removal; the overwhelming authority of the master, reducing the dependence of children on their parents and the economic role of the male household head. Yet, in spite of these stresses, there is evidence of strong bonds of kinship and sense of family among the slaves. 相似文献
475.
Orion Mowbray Bryan G. Victor Joseph P. Ryan Andrew Moore Brian E. Perron 《Journal of social work practice in the addictions》2017,17(4):352-373
Foster care involvement due to parental substance use is a common problem with many challenges associated with service delivery. Using administrative data from a Midwestern state between the years 2009 and 2015 (N = 17,420), this study examines characteristics of substance-abusing families at the time of entry into the foster care system and estimates the risk of reentry subsequent to reunification. Bivariate findings and survival analysis for reentry suggests substance-using parents are more likely to be involved in additional allegations associated with foster care involvement. These results highlight the need for improved services integration and coordinated delivery among service systems. 相似文献
476.
477.
Unconventional shale oil and gas production plays a prominent role in boosting economic growth and stimulating wealth creation in many communities. However, because of potential social and environmental drawbacks, including a lack of affordable housing and groundwater contamination from drilling, unconventional shale development is highly contentious in many areas and has resulted in many community conflicts. Hydraulic fracturing, which is a specific technology utilized in unconventional shale development, has proved especially contentious because of concerns about its long‐term environmental consequences. Given the fast pace of shale development, coupled with the controversy that surrounds it, we seek to understand what factors affect a local government official's stance on shale development and hydraulic fracturing. To do this we draw from value‐belief‐norms theory while additionally examining knowledge and community‐level factors that can influence an official's position. In this study, we survey 308 local government officials across six shale plays in the United States to examine local officials' positions on shale development and hydraulic fracturing. We find that the more positively officials perceive the consequences of shale development, the less likely they are to support banning hydraulic fracturing. Additionally, we find that networks to other shale communities are positively associated with favoring a ban. Further, leaders with a bachelor's degree or higher are more likely to favor a ban than those with lower than a bachelor's degree. 相似文献
478.
Theory and Society - 相似文献
479.
Jason P. Kaye Sara E. Eckert Daniel A. Gonzales Jonathan O. Allen Sharon J. Hall Ryan A. Sponseller Nancy B. Grimm 《Urban Ecosystems》2011,14(4):737-754
Urban atmospheres can have high concentrations of particulate organic carbon (oC) but the rate and fate oC deposition in near-urban ecosystems are rarely quantified. We collected atmospheric particulate matter in Phoenix, AZ and applied these samples to Sonoran Desert soils in a series of laboratory incubation experiments. The addition of fine particulate matter (<2.5 μm aerodynamic diameter) increased microbial respiration in soils collected from the interspaces between desert shrubs. The increase in soil respiration was equivalent to 25% to 30% of the added oC. In contrast, we did not detect increases in respiration when coarse particulate matter (>2.5 μm aerodynamic diameter) was added to interspace soils, suggesting that coarse particulate oC is recalcitrant to microbial decomposition. Due to comparatively higher background levels of C mineralization, we rarely detected changes in microbial respiration when fine or coarse particulate oC was added to soils collected beneath shrub canopies. We measured total atmospheric C concentrations within and surrounding Phoenix and, using inferential methods, estimated rates of deposition that ranged from 0.02 to 0.58 mg C m−2 d−1 for fine particles and from 0 to 6.15 mg C m−2 d−1 for coarse particles. Results show that fine atmospheric particulate matter deposited at low rates downwind of Phoenix is a labile oC substrate for soil heterotrophs. In contrast, oC deposited at higher rates as coarse particulate matter may accumulate in soils due to slow microbial decomposition rates. 相似文献
480.
Felicity Scott BSc Ryan E. Rhodes PhD Danielle Symons Downs PhD 《Journal of American college health : J of ACH》2013,61(3):213-222
Abstract Objective: Public health messaging about physical activity (PA) sometimes combines moderate and vigorous intensity, but the variance/invariance of the motives for PA by intensity has received scant attention. Thus, the purpose of this study was to examine the beliefs and motivations associated with regular moderate- and vigorous-intensity PA in a college sample using the framework of Ajzen's Theory of Planned Behavior (TPB). Participants and Methods: A college sample of 337 participants was randomly assigned to complete measures of the TPB framed for either vigorous- or moderate-intensity PA and subsequently completed self-reported measures of PA 2 weeks later. Results: Mean comparisons indicated that participants held higher mean behavioral beliefs about the benefits of vigorous PA for improving appearance and fitness, but vigorous PA was perceived to take more time than moderate-intensity activities. A stacked structural equation model and follow-up Fisher z tests, however, suggested no differences between the associations of TPB constructs with intention or PA by intensity. Conclusions: The findings provide support for the current public health approach of combining moderate and vigorous physical activity messaging through the general invariance of motives by intensity. 相似文献