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   266篇
  免费   7篇
  2024年   2篇
  2023年   8篇
  2022年   4篇
  2021年   4篇
  2020年   12篇
  2019年   10篇
  2018年   8篇
  2017年   6篇
  2016年   2篇
  2015年   7篇
  2014年   8篇
  2013年   23篇
  2012年   14篇
  2011年   16篇
  2010年   14篇
  2009年   24篇
  2008年   20篇
  2007年   24篇
  2006年   12篇
  2005年   10篇
  2004年   6篇
  2003年   11篇
  2002年   5篇
  2001年   2篇
  2000年   3篇
  1999年   4篇
  1998年   5篇
  1997年   2篇
  1996年   1篇
  1995年   1篇
  1994年   1篇
  1991年   2篇
  1988年   1篇
  1985年   1篇
排序方式: 共有273条查询结果,搜索用时 15 毫秒
1.
ABSTRACT. This paper introduces the household interactive variable input-output (HIVIO) model to measure the effect of cost variation on industrial outputs. The model produces a variety of cost elasticities that separate out impacts on industrial prices, imports, and outputs, with “own” and “cross” elasticity components. Like the conventional input-output multipliers, these cost elasticities can be useful parameters to evaluate the substituting behavior of firms and consumers. By using the 1980 Korean input-output transactions table, we find the wage and import price effects on industrial prices, outputs, and import demands.  相似文献   
2.
The Multiregional Variable Input-Output (MRVIO) model is introduced to measure the development impact of a transportation system. The MRVIO model is a theoretically flexible, computationally simple, and cost-responsive model. Under the MRVIO model, regional input-output coefficients, trade coefficients, and trade flows become cost responsive and easy to compute. The MRVIO model is employed to measure the development impact of the Arkansas waterway during the period of 1974 to 1978. In the study, the U.S. economy is disaggregated into 3 regions and 35 industrial sectors. The MRVIO model estimates the economic conditions of these 3 regions with and without the waterway in terms of industrial output, income, employment, and trade flows.  相似文献   
3.
4.
Pan, Z., Zhu, M., Zhu, Y. &; Jia, L., August 2017. A new antiarch placoderm from the Emsian (Early Devonian) of Wuding, Yunnan, China. Alcheringa 42, 10–21. ISSN 0311-5518.

Wufengshania magniforaminis, a new genus and species of the Euantiarcha (Placodermi: Antiarcha), is described from the late Emsian (Early Devonian) of Wuding, Yunnan, southwestern China. The referred specimens were three-dimensionally preserved in black shales, allowing a high-resolution computed tomography reconstruction of anatomical details. The new euantiarch is characterized by a large orbital fenestra, an arched exoskeletal band around the orbital fenestra and a developed obtected nuchal area of the skull roof. Maximum parsimony analysis, using a revised data-set of antiarchs with 44 taxa and 66 characters, resolves Wufengshania gen. nov. as a member of the Bothriolepididae, which is characterized by the presence of the infraorbital sensory canal diverging on the lateral plate, and the nuchal plate with orbital facets. New analysis supports a sister group relationship between Dianolepis and the Bothriolepididae. Luquanolepis, a coeval euantiarch from the neighboring site of the new form, is referred to the Asterolepidoidei and represents the basalmost and earliest member of the Asterolepidoidei.

Zhaohui Pan* [], Min Zhu* [], You’an Zhu? [] and Liantao Jia [] Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, PO Box 643, Beijing 100044, PR China. *Also affiliated with University of Chinese Academy of Sciences, Beijing, 100049, PR China. ?Also affiliated with Uppsala University, PO Box 256, 751 05 Uppsala, Sweden.  相似文献   
5.
6.
In crime analyses, maps showing the degree of risk help police departments to make decisions on operational matters, such as where to patrol or how to deploy police officers. This study statistically models spatial crime data for multiple crime types in order to produce joint crime risk maps. To effectively model and map the spatial crime data, we consider two important characteristics of crime occurrences: the spatial dependence between sites, and the dependence between multiple crime types. We reflect both characteristics in the model simultaneously using a generalized multivariate conditional autoregressive model. As a real‐data application, we examine the number of incidents of vehicle theft, larceny, and burglary in 83 census tracts of San Francisco in 2010. Then, we employ a Bayesian approach using a Markov chain Monte Carlo method to estimate the model parameters. Based on the results, we detect the crime hotspots, thus demonstrating the advantage of using a multivariate spatial analysis for crime data.  相似文献   
7.
陶敏 《文献》2007,(2):89-94
宋太祖开宝三年(970),南唐清辉殿学士张洎奉命使宋,纪录宋典客、左补阙贾黄中谈话,撰成<贾氏谈录>一书.此书虽记唐代琐事,又仅一卷,"篇帙无多,然如牛李之党其初肇衅于口语,为史所未及,而<周秦行纪>一书,晁公武亦尝据此录以辨韦璀之诬.  相似文献   
8.
将铜器刻文与史籍对照研究,从而对刻文作出新的解释.  相似文献   
9.
从《申报》看苏州的私钱与禁私(1827-1877)   总被引:1,自引:1,他引:0  
黄敏 《中国钱币》2007,(4):37-40
清代实行银钱平行本位,大数用银,小数用钱。制钱是民间主要的流通货币,银两只不过是国家财政和大宗贸易的计算出纳单位以及富裕人家的储藏手段。在清朝统治者入关前,就曾铸有“天命”、“天聪”两种铜钱,自顺治进关,到辛亥革命,前后历经十代皇帝,铸有十种年号钱。康熙、乾隆时代的铜钱质量、重量都很规范。  相似文献   
10.
郭敏 《中原文物》2007,37(2):25-31
依据考古发掘和文献资料,认为史前先民对头部的装饰手法多种多样,这在一定程度上反映了早期人类审美意识及淳朴的原始宗教信仰的多样化,同时也说明了古人对美的追求并非有了丰厚的物质条件才萌生的。  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