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   4338篇
  免费   175篇
  2020年   62篇
  2019年   68篇
  2018年   103篇
  2017年   115篇
  2016年   110篇
  2015年   99篇
  2014年   89篇
  2013年   1105篇
  2012年   136篇
  2011年   121篇
  2010年   110篇
  2009年   144篇
  2008年   168篇
  2007年   117篇
  2006年   93篇
  2005年   60篇
  2004年   69篇
  2003年   64篇
  2002年   57篇
  2001年   93篇
  2000年   66篇
  1999年   61篇
  1998年   43篇
  1997年   35篇
  1996年   48篇
  1995年   48篇
  1994年   39篇
  1993年   48篇
  1992年   36篇
  1991年   39篇
  1990年   30篇
  1989年   42篇
  1988年   39篇
  1987年   42篇
  1986年   38篇
  1985年   42篇
  1984年   51篇
  1983年   61篇
  1982年   45篇
  1981年   44篇
  1980年   48篇
  1979年   41篇
  1978年   52篇
  1977年   49篇
  1976年   53篇
  1975年   32篇
  1974年   30篇
  1973年   31篇
  1972年   34篇
  1971年   31篇
排序方式: 共有4513条查询结果,搜索用时 31 毫秒
111.
112.
ABSTRACT. Data for 28 metropolitan areas over a 15-year period are used to determine the impacts of government spending, taxes, and public infrastructure on total employment and disaggregated employment. After carefully controlling for the government budget constraint we find that taxes are negatively related to total employment and education spending is positively related to total employment. Nevertheless, we find that it is difficult for metropolitan areas to influence the composition of their employment with government tax and expenditure policies. Moreover, at current levels of public infrastructure, marginal changes in infrastructure have no strong effect on employment.  相似文献   
113.
114.
115.
Peter GARNSEY & Richard SALLER, L'Empire romain. Economie, société, culture, Paris, La Découverte / Textes à l'appui, 1994.

Morris SLAVIN, The Hébertistes to the Guillotine: anatomy of a ‘conspiracy’ in Revolutionary France, Louisiana State University Press, Baton Rouge and London, 1994, xvii + 280 p., ISBN 0–8071–1838–9.

Philippe BURRIN, La France à l'heure allemande, 1940–1944, Paris, Editions du Seuil, 1995.

Emmanuel LE ROY LADURIE, Le siècle des Platter 1499–1628, t.1 “Le mendiant et le professeur”, Paris, Fayard, 1995, 529 p., 170 FF., ISBN 2–213–01444–2.  相似文献   

116.
Abstract. This article considers the debate that has recently developed in studies of nationalism between those scholars who see the nation as a modern and constantly changing construction ex nihilo and those who see it as an immemorial, unchanging communal essence. It outlines the so-called ‘gastronomical’ and ‘geological’ metaphors of nation formation and suggests a synthetic model which balances the influence of the ethnic past and the impact of nationalist activity. It shows that the central question which has divided theorists of nationalism is the place of the past in the life of modern nations. The author recognises the role of nationalists in national mobilisation but stresses that nationalists are not social engineers or mere image makers as modernist and post-modernist accounts would have it, but rather social and political archaeologists whose activities consist in the rediscovery and reinterpretation of the ethnic past and through it the regeneration of their national community.  相似文献   
117.
118.
Random Time Sampling is an innovative data collection method which has potential for adaptation and use by geographers. Individual pocket-sized programmable beepers were used in a pilot study of the uses of time by older households and older people's attitudes to different activities. Random beeps were used to prompt individuals living in eleven Melbourne suburbs to record time use data in diaries over a period of a week. The method proved extremely effective and reliable, and many participants reporting that they enjoyed the exercise.  相似文献   
119.
A trial, monitored release on the Wingecarribee River over 27 days had a peak discharge below the Wingecarribee Dam of 1090 ML/d, which had a flow duration of 0.95 per cent. Morphological impacts on 29 km of channel below the dam included bank erosion, concentrated neck overflow, bed degradation and channel widening at recent cutoffs, sedimentation in weir pools and overbank flow, particularly at discharges greater than 800 ML/d. Prolonged operational releases at bankfull discharge (400–800 ML/d) will have the greatest morphologic impacts and should be avoided. Pulses which dissipate stream power over a broad, well-vegetated floodplain should be incorporated in the operational release policy, provided such pulses are phased to facilitate channel and vegetation recovery.  相似文献   
120.
There is increasing concern about environmental impacts of acidic drainage from acid sulphate soils on Holocene estuarine flood plains. Acidity derives from oxidation of iron pyrite in the sediments. Natural factors determine concentrations and distributions of pyrite accumulations, but human activities have reduced pyrite accumulation in the Pearl River Delta with land use practices increasing terrestrial sediment discharge. Large freshwater discharges and management techniques have enabled sustainable use of these soils. High concentrations of pyrite occur in many estuarine flood plains of Australia because of relatively greater marine inputs. Drainage of these soils enhances pyrite oxidation and estuarine acidification, which is associated with fish-kills. For sustainable development, the problems of acid sulphate soil drainage must be recognised and overcome.  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