全文获取类型
收费全文 | 90303篇 |
免费 | 1959篇 |
国内免费 | 5篇 |
专业分类
管理学 | 12326篇 |
民族学 | 542篇 |
人才学 | 26篇 |
人口学 | 6807篇 |
丛书文集 | 531篇 |
教育普及 | 2篇 |
理论方法论 | 9343篇 |
综合类 | 2198篇 |
社会学 | 41744篇 |
统计学 | 18748篇 |
出版年
2023年 | 506篇 |
2021年 | 567篇 |
2020年 | 1504篇 |
2019年 | 2203篇 |
2018年 | 2053篇 |
2017年 | 3110篇 |
2016年 | 2360篇 |
2015年 | 2035篇 |
2014年 | 2611篇 |
2013年 | 18806篇 |
2012年 | 2331篇 |
2011年 | 2135篇 |
2010年 | 1963篇 |
2009年 | 2179篇 |
2008年 | 2006篇 |
2007年 | 1841篇 |
2006年 | 2078篇 |
2005年 | 2270篇 |
2004年 | 2137篇 |
2003年 | 1866篇 |
2002年 | 1972篇 |
2001年 | 1964篇 |
2000年 | 1747篇 |
1999年 | 1655篇 |
1998年 | 1487篇 |
1997年 | 1323篇 |
1996年 | 1308篇 |
1995年 | 1314篇 |
1994年 | 1282篇 |
1993年 | 1274篇 |
1992年 | 1251篇 |
1991年 | 1185篇 |
1990年 | 1160篇 |
1989年 | 1008篇 |
1988年 | 1109篇 |
1987年 | 978篇 |
1986年 | 863篇 |
1985年 | 1050篇 |
1984年 | 1109篇 |
1983年 | 998篇 |
1982年 | 926篇 |
1981年 | 838篇 |
1980年 | 803篇 |
1979年 | 866篇 |
1978年 | 762篇 |
1977年 | 685篇 |
1976年 | 652篇 |
1975年 | 629篇 |
1974年 | 509篇 |
1973年 | 437篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
781.
The mean density of bacteria in a water body is commonly monitored using quantal assay. This paper describes the use of local scoring in estimating the spatial distribution of mean density from quantal assay results at a set of point locations. An application to estimating the mean density of fecal conform bacteria in a coastal pond is presented. Model diagnostics based on a parametric bootstrap are also presented. 相似文献
782.
The possibility that carbon dioxide emissions from fossil fuel use might lead to global warming has become a leading environmental concern. Many scientific and environmental organizations have called for immediate action to limit carbon dioxide production. For the most part, however, public debate has focused on a single policy instrument: a carbon tax applied to fossil fuels in proportion to their carbon content. We present a detailed model of the U.S. economy and use it to compare carbon taxes with two other instruments that could achieve the same reduction in carbon dioxide emissions: a tax on the energy content of fossil fuels (a BTU tax) and an ad valorem tax on fuel use. We find that carbon taxes can achieve a given reduction with the least overall effect on the economy, but with a large effect on coal mining. Energy taxes are fairly similar to carbon taxes but have slightly less impact on coal mining and slightly greater overall cost. In contrast, ad valorem taxes fall much more lightly on coal mining but have a much greater effect on the economy as a whole. 相似文献
783.
784.
A training project in a northern Canadian community providedan opportunity to examine participatory planning approachesand the meaning of work in First Nations communities. Focusgroups conducted three years after the unsuccessful interventionof a community economic development (CED) project suggest thatcomplex factors such as lack of support from community leadersand rate of pay for workers determine whether CED is alwaysappropriate in northern, First Nations contexts. 相似文献
785.
Given the fragmented structure of child‐care assistance in the United States, it has been difficult to obtain accurate estimates of which families are assisted, through which mechanisms, and at what level. Making use of survey data from New York City, we analyze the distribution of several forms of public child‐care assistance. Results suggest that about 40% of all families with young children receive some form of child‐care assistance. Considering all forms of assistance, the distribution of child‐care help is targeted in both expected and some unexpected ways. Implications of these results are discussed in the context of U.S. child‐care policies governing access and benefit levels. 相似文献
786.
Jarrett J. Barber Alan E. Gelfand John A. Silander 《Revue canadienne de statistique》2006,34(4):659-676
The authors consider the issue of map positional error, or the difference between location as represented in a spatial database (i.e., a map) and the corresponding unobservable true location. They propose a fully model‐based approach that incorporates aspects of the map registration process commonly performed by users of geographic informations systems, including rubber‐sheeting. They explain how estimates of positional error can be obtained, hence estimates of true location. They show that with multiple maps of varying accuracy along with ground truthing data, suitable model averaging offers a strategy for using all of the maps to learn about true location. 相似文献
787.
Ohne Zusammenfassung
Rede zum 100. Geburtstag auf einer Veranstaltung der Stadt K?ln, der René-K?nig-Gesellschaft und des Westdeutschen Rundfunks
K?ln am 11. Mai 2006 in K?ln 相似文献
788.
PD Dr. Gerd Nollmann 《KZfSS K?lner Zeitschrift für Soziologie und Sozialpsychologie》2006,58(4):638-659
The article tests the thesis that globalization increases the earnings inequality of households. It extends the time series data set of Alderson and Nielsen (2002) who supported the globalization thesis. Alternative models provide no evidence that foreign trade, foreign investment, and migration increase inequality. The article gives reasons for these results and shows that OECD countries pass through an endogenous sectoral and demographic crisis in the transition to post-industrial service societies. Therefore, the paper adapts Kuznets’ theorem of sector dualism to the subsectors of the service economy. The polarization of value addition within the service sector appears as the crucial determinant of increased earnings inequality of households. 相似文献
789.
Are the decisions of American policymakers informed by generaltrends in the publics ideology or by the publicspolicy-specific preferences? In this article we discuss twoexplanations for the types of public opinion information thatpoliticians collect and use. Using a unique data set of privatepolls from the White House of Richard Nixon, we find that whenopinion data on specific policies were available, the presidentrelied on them and not on general ideology data. On less importantissues, however, we find that the president often chose notto collect policy-specific data and instead relied on generalideology data. The differential collection and use of informationby policymakers reflect varying strategic calculations. Theyalso have profound implications for representative democracyand the demands placed on citizens and governors. 相似文献
790.
Abstract The AIDS epidemic was initially thought to be primarily an urban phenomenon. However, migration between rural and urban areas has resulted in the spread of the virus to all segments of the population. Prevention efforts continue to focus on the ABCs of AIDS, namely, abstinence among young adults, being faithful within a monogamous relationship, and/or using condoms at each sexual encounter. We examine the effects of residence, migration status, and selected social and demographic variables on the use of these three practices among men in Zimbabwe, a nation experiencing one of the highest HIV/AIDS prevalence rates in the world. Both residence and migration status were found to be significantly related to safe sex practices. Knowledge of a source with easy access to condoms was the strongest predictor of this behavior. Knowledge of prevention methods and experience with persons with AIDS also exerted significant effects, although not always in the manner hypothesized. Possible reasons for the findings and implications for policy are discussed. 相似文献