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   5646篇
  免费   254篇
  2020年   63篇
  2019年   97篇
  2018年   160篇
  2017年   141篇
  2016年   187篇
  2015年   115篇
  2014年   124篇
  2013年   1669篇
  2012年   147篇
  2011年   174篇
  2010年   152篇
  2009年   157篇
  2008年   122篇
  2007年   127篇
  2006年   126篇
  2005年   67篇
  2004年   83篇
  2003年   86篇
  2002年   58篇
  2001年   86篇
  2000年   68篇
  1999年   78篇
  1998年   67篇
  1997年   63篇
  1996年   54篇
  1995年   53篇
  1994年   44篇
  1993年   61篇
  1992年   55篇
  1990年   46篇
  1989年   57篇
  1988年   45篇
  1987年   52篇
  1986年   48篇
  1985年   54篇
  1984年   53篇
  1983年   77篇
  1982年   59篇
  1981年   54篇
  1980年   57篇
  1979年   54篇
  1978年   61篇
  1977年   64篇
  1976年   51篇
  1975年   52篇
  1974年   43篇
  1973年   47篇
  1972年   42篇
  1971年   42篇
  1969年   40篇
排序方式: 共有5900条查询结果,搜索用时 15 毫秒
51.
52.
ABSTRACT. This paper presents a statistical procedure for empirically establishing linkages between regional economies. Using Granger's definition of causality and the final prediction error technique for lag-length specification suggested by Hsiao, a linked, multiregional employment model is developed. The forecast performance of the linked model is compared to models which do not include interregional linkages. It is shown that forecast error is reduced by taking into account employment interrelationships between regions.  相似文献   
53.
54.
55.
Results suggest that ESR studies of Mn+2 in marble can provide an excellent discriminator for the determination of marble provenance. In comparison with other methods of quantitative analysis for manganese such as AA or NAA, the ESR method determines only Mn+2 rather than total Mn, is inexpensive and rapid with no chemical preparation required, and does not consume the sample.  相似文献   
56.
57.
A number of investigations have been undertaken by the New South Wales Water Resources Commission to determine the regional and compound effects of large scale extractive industries on the stability of the Hunter River, New South Wales. Sedimentologic studies of bed material suggest that the Hunter River upstream of Denman has an armoured gravel bed that is immobile during regulated releases from Glenbawn Dam but is disrupted by moderate but less than bankfull flows. Annual bedloadyields have been computed by the bedload rating-flow duration technique for five river gauging stations. Approximate sand and gravel budgets for selected reaches of the Hunter River demonstrate that the present annual extraction rate from temporary sediment storages within the channel greatly exceeds the transport rate upstream of Denman and is approximately equal to the transport rate downstream of Denman. River degradation is imminent if extractive industries continue operating in the channel of the Hunter River  相似文献   
58.
59.
60.
ABSTRACT This paper develops a general multimarket hedonic model appropriate for a national, interregional study of wages, housing prices, and location-specific amenities. The model encompasses the effects of interregional location, intraurban location, and city size. Typically, hedonic studies focus on a single market such as labor or housing and ignore interactions implicit in a more global compensation mechanism. Examination of the comparative statics of our model indicates that single-market differentials are partial prices and are unreliable measures of amenity values in an interregional context. Unbiased amenity values are estimated for a comprehensive set of amenities using data on housing prices for 34,414 households and wages for 46,004 workers from the 1980 Census of Population and Housing. Statistically significant differences in housing prices and wages are found due to amenities.  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