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   675篇
  免费   27篇
管理学   108篇
民族学   2篇
人口学   56篇
丛书文集   1篇
理论方法论   90篇
综合类   2篇
社会学   377篇
统计学   66篇
  2023年   6篇
  2022年   7篇
  2021年   3篇
  2020年   19篇
  2019年   24篇
  2018年   17篇
  2017年   41篇
  2016年   31篇
  2015年   21篇
  2014年   33篇
  2013年   112篇
  2012年   28篇
  2011年   36篇
  2010年   23篇
  2009年   20篇
  2008年   20篇
  2007年   17篇
  2006年   12篇
  2005年   17篇
  2004年   14篇
  2003年   16篇
  2002年   24篇
  2001年   13篇
  2000年   7篇
  1999年   13篇
  1998年   7篇
  1997年   7篇
  1996年   6篇
  1995年   6篇
  1994年   5篇
  1993年   9篇
  1992年   12篇
  1991年   6篇
  1990年   8篇
  1989年   4篇
  1988年   4篇
  1987年   4篇
  1985年   2篇
  1984年   5篇
  1983年   8篇
  1982年   4篇
  1981年   5篇
  1980年   6篇
  1979年   2篇
  1978年   3篇
  1977年   4篇
  1976年   3篇
  1971年   2篇
  1968年   1篇
  1967年   1篇
排序方式: 共有702条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
Summary.  Official employment-related performance indicators in UK higher education are based on the population of students responding to the 'First destination supplement' (FDS). This generates potentially biased performance indicators as this population of students is not necessarily representative of the full population of leavers from each institution. University leavers who do not obtain qualifications and those who do not respond to the FDS are not included within the official analysis. We compare an employment-related performance indicator based on those students who responded to the FDS with alternative approaches which address the potential non-random nature of this subgroup of university leavers.  相似文献   
5.
6.
7.
8.
9.
The American diet has changed substantially over the last few decades. These changes provide a test for social theory and have substantial effects on the demand for various food products, thus impacting U.S. agriculture. In this paper a rapidly growing dietary choice—vegetarianism—is explored. Prevalence of various forms of vegetarianism is estimated in a representative sample of a suburban population and factors that influence choice of a vegetarian diet are examined. About 7 percent of the sample report they are vegetarians. The prevalence of vegetarianism is not influenced by age, gender, or education, but individuals holding traditional values are less likely to be vegetarian than others. There also is some evidence mat individuals holding altruistic values are more likely than others to be vegetarians.  相似文献   
10.
Tree health is a critical parameter for evaluating urban ecosystem health and sustainability. Traditionally, this parameter has been derived from field surveys. We used multispectral remote sensing data and GIS techniques to determine tree health at the University of California, Davis. The study area (363 ha) contained 8,962 trees of 215 species. Tree health conditions were mapped for each physiognomic type at two scales: pixel and whole tree. At the pixel scale, each tree pixel within the tree crown was classified as either healthy or unhealthy based on vegetation index values. At the whole tree scale, raster based statistical analysis was used to calculate tree health index which is the ratio of healthy pixels to entire tree pixels within the tree crown. The tree was classified as healthy if the index was greater than 70%. Accuracy was checked against a random sample of 1,186 trees. At the whole tree level, 86% of campus trees were classified as healthy with 88% mapping accuracy. At the pixel level, 86% of the campus tree cover was classified as healthy. This tree health evaluation approach allows managers to identify the location of unhealthy trees for further diagnosis and treatment. It can be used to track the spread of disease and monitor seasonal or annual changes in tree health. Also, it provides tree health information that is fundamental to modeling and analysis of the environmental, social, and economic services produced by urban forests.  相似文献   
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