首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   29103篇
  免费   568篇
  国内免费   96篇
管理学   4083篇
劳动科学   1篇
民族学   144篇
人才学   1篇
人口学   2466篇
丛书文集   557篇
教育普及   2篇
理论方法论   2448篇
现状及发展   1篇
综合类   2744篇
社会学   12699篇
统计学   4621篇
  2022年   136篇
  2021年   225篇
  2020年   404篇
  2019年   511篇
  2018年   619篇
  2017年   818篇
  2016年   656篇
  2015年   536篇
  2014年   734篇
  2013年   4241篇
  2012年   956篇
  2011年   1042篇
  2010年   867篇
  2009年   787篇
  2008年   862篇
  2007年   877篇
  2006年   902篇
  2005年   806篇
  2004年   660篇
  2003年   603篇
  2002年   667篇
  2001年   740篇
  2000年   712篇
  1999年   599篇
  1998年   459篇
  1997年   423篇
  1996年   438篇
  1995年   411篇
  1994年   410篇
  1993年   405篇
  1992年   458篇
  1991年   457篇
  1990年   435篇
  1989年   407篇
  1988年   420篇
  1987年   371篇
  1986年   354篇
  1985年   392篇
  1984年   381篇
  1983年   358篇
  1982年   294篇
  1981年   249篇
  1980年   238篇
  1979年   291篇
  1978年   256篇
  1977年   218篇
  1976年   203篇
  1975年   200篇
  1974年   184篇
  1973年   159篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
161.
162.
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   
163.
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   
164.
This study examines school enrollment in two sub-Saharan African nations, Malawi and Kenya. The article advances a refined family economy theoretical framework for understanding variations in school enrollment. It recasts family economy frameworks to consider not only how the household institution mediates a broad social change, but also how the family institution itself may be influenced by a macroinstitutional change. The findings suggest that household structural changes, as well as changes in parents' activities and perceptions, help explain enrollment practices in rural Malawi and Kenya.  相似文献   
165.
This article is concerned with the determinants of English language proficiency among immigrants in a longitudinal survey for Australia. It focuses on both visa category and variables derived from an economic model of the determinants of destination‐language proficiency among immigrants. Skills‐tested and economic immigrants have the greatest proficiency shortly after immigration, followed by family‐based visa recipients, with refugees having the lowest proficiency. Other variables the same, these differences disappear by 3.5 years after immigration for speaking skills; and although they diminish, they persist longer for reading and writing skills. The variables generated from the model of destination‐language proficiency (such as schooling and age at migration) are, in part, predictions of visa category, but they are more important statistically for explaining proficiency.  相似文献   
166.
In studies of farming, the age of the principal decision-maker (PDM) has been associated with numerous farm structural and managerial features and has been widely accepted as a good indicator of the influence of life-cycle factors on decision-making. As such, it has become an important aspect of many quantitative studies of agricultural change. However, contemporary studies of family farming demonstrate that the concept of a single PDM in family farms is becoming an anachronism as alternative enterprises, pluriactivity and the scale of family farms force more diffuse management/operating systems. This raises questions concerning whether the age of the PDM can still be taken as representative of farm structure, strategy or life-cycle stage? Using a study conducted in the Grampian Mountains region of Scotland in 2003 this note investigates the impact of using an alternative index—compiled by averaging the age of family members working on the farm. It suggests that PDM age is a relatively poor indicator of farm structural and managerial features compared to a family age index and calls for researchers to think about alternative approaches to measuring ‘age’ as an indicator.  相似文献   
167.
Child welfare workers and agencies are vulnerable to lawsuits. Recent court rulings have more clearly defined the liability of workers. The distinguishing variable is custody. Children injured while in the custody of the state are entitled to sue for damages. Children injured by their parent, even if under the supervision of a child welfare agency, are not entitled to claim a violation of their 14th Amendment rights. These cases are reviewed and strategies designed to minimize vulnerability are offered.  相似文献   
168.
169.
Rates of problem or probable pathological gambling were assessed in substance abusers seeking outpatient treatment in a publicly funded outpatient substance abuse treatment program. The South Oaks Gambling Screen (SOGS) was administered to 467 consecutive admissions at three different sites. Problem gamblers comprised 6.2 percent of the total (n=29), and 4.5 percent scored as probable pathological gamblers (n=21). These rates are two and one-half times greater than would be expected according to a recent state survey using the SOGS. Implications for assessment and treatment of problem gambling are discussed.The author expresses his appreciation to John Ramsay and the staff of Epoch Counseling Center for data collection; to Les Franklin for computational analysis; and Dr. Rachel Volberg for providing supplemental data from her Maryland State Gambling Survey.  相似文献   
170.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号