全文获取类型
收费全文 | 7679篇 |
免费 | 125篇 |
国内免费 | 1篇 |
专业分类
管理学 | 1034篇 |
民族学 | 33篇 |
人口学 | 779篇 |
丛书文集 | 33篇 |
理论方法论 | 680篇 |
综合类 | 92篇 |
社会学 | 3709篇 |
统计学 | 1445篇 |
出版年
2023年 | 42篇 |
2020年 | 98篇 |
2019年 | 143篇 |
2018年 | 170篇 |
2017年 | 255篇 |
2016年 | 181篇 |
2015年 | 128篇 |
2014年 | 160篇 |
2013年 | 1332篇 |
2012年 | 231篇 |
2011年 | 212篇 |
2010年 | 151篇 |
2009年 | 136篇 |
2008年 | 151篇 |
2007年 | 148篇 |
2006年 | 179篇 |
2005年 | 160篇 |
2004年 | 155篇 |
2003年 | 139篇 |
2002年 | 162篇 |
2001年 | 168篇 |
2000年 | 172篇 |
1999年 | 181篇 |
1998年 | 141篇 |
1997年 | 138篇 |
1996年 | 131篇 |
1995年 | 112篇 |
1994年 | 112篇 |
1993年 | 114篇 |
1992年 | 120篇 |
1991年 | 132篇 |
1990年 | 132篇 |
1989年 | 150篇 |
1988年 | 91篇 |
1987年 | 113篇 |
1986年 | 97篇 |
1985年 | 120篇 |
1984年 | 97篇 |
1983年 | 110篇 |
1982年 | 82篇 |
1981年 | 87篇 |
1980年 | 77篇 |
1979年 | 83篇 |
1978年 | 87篇 |
1977年 | 69篇 |
1976年 | 69篇 |
1975年 | 63篇 |
1974年 | 65篇 |
1973年 | 51篇 |
1971年 | 44篇 |
排序方式: 共有7805条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
5.
Diane Hope Weixing Zhu Corinna Gries Jacob Oleson Jason Kaye Nancy B. Grimm Lawrence A. Baker 《Urban Ecosystems》2005,8(3-4):251-273
We explored variations in inorganic soil nitrogen (N) concentrations across metropolitan Phoenix, Arizona, and the surrounding
desert using a probability-based synoptic survey. Data were examined using spatial statistics on the entire region, as well
as for the desert and urban sites separately. Concentrations of both NO3-N and NH4-N were markedly higher and more heterogeneous amongst urban compared to desert soils. Regional variation in soil NO3-N concentration was best explained by latitude, land use history, population density, along with percent cover of impervious
surfaces and lawn, whereas soil NH4-N concentrations were related to only latitude and population density. Within the urban area, patterns in both soil NO3-N and NH4-N were best predicted by elevation, population density and type of irrigation in the surrounding neighborhood. Spatial autocorrelation
of soil NO3-N concentrations explained 49% of variation among desert sites but was absent between urban sites. We suggest that inorganic
soil N concentrations are controlled by a number of ‘local’ or ‘neighborhood’ human-related drivers in the city, rather than
factors related to an urban-rural gradient. 相似文献
6.
Modeling cooperation among self-interested agents: a critique 总被引:2,自引:0,他引:2
This paper reviews recent attempts to model cooperation in groups of self-interested unrelated individuals. It concludes that no empirically plausible model has been developed, and the economist's quest for an explanation of human prosociality in terms of self-interested agents has not been successful. We show that the equilibrium criteria employed in standard game-theoretic models have no attractive dynamic properties, and the mechanisms deployed in these models are not generally seen in empirical examples of cooperative groups. We also show that these models are not robust to plausible rates of signaling error and mutation. We present an alternative, involving strongly reciprocal agents, that satisfies all the requirements for a dynamically stable model of cooperation. 相似文献
7.
The Coase theorem maintains that where free-market precepts exist, the allocation of property rights does not impact the distribution of resources. An application to Major League Baseball suggests that institutions such as free agency and the reverse-order amateur draft would not impact player distributions and therefore would not impact competitive balance. The present study finds that the distribution of wins is generally consistent with the precepts of the Coase theorem and therefore suggests a course for those who wish to alter the level of competitive balance: Major League Baseball should increase its focus on expanding the size of its labor pool. (JEL O15 , L83 , C22 ) 相似文献
8.
UNDERSTANDING THE DECISION TO PARTICIPATE IN A SURVEY 总被引:18,自引:1,他引:17
The lack of full participation in sample surveys threatens theinferential value of the survey method. We review a set of conceptualdevelopments and experimental findings that appear to be informativeabout causes of survey participation; offer an integration ofthat work with findings from the more traditional statisticaland survey methodological literature on nonresponse; and, giventhe theoretical structure, deduce potentially promising pathsof research toward the understanding of survey participation. 相似文献
9.
10.