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   15530篇
  免费   582篇
  2020年   192篇
  2019年   284篇
  2018年   318篇
  2017年   379篇
  2016年   497篇
  2015年   327篇
  2014年   317篇
  2013年   4394篇
  2012年   413篇
  2011年   447篇
  2010年   465篇
  2009年   414篇
  2008年   373篇
  2007年   371篇
  2006年   349篇
  2005年   209篇
  2004年   207篇
  2003年   189篇
  2002年   200篇
  2001年   231篇
  2000年   212篇
  1999年   266篇
  1998年   180篇
  1997年   132篇
  1996年   158篇
  1995年   158篇
  1994年   154篇
  1993年   166篇
  1992年   156篇
  1991年   125篇
  1990年   117篇
  1989年   139篇
  1988年   138篇
  1987年   147篇
  1986年   138篇
  1985年   186篇
  1984年   183篇
  1983年   211篇
  1982年   168篇
  1981年   164篇
  1980年   169篇
  1979年   165篇
  1978年   154篇
  1977年   160篇
  1976年   148篇
  1975年   153篇
  1974年   129篇
  1973年   126篇
  1972年   113篇
  1970年   96篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
43.
44.
"A model of private local labor demand and interjurisdictional migration is presented and estimated using data from Swedish counties and municipalities for 1979-84. Our goal is to compare the effects on local labor markets of distinctive public-sector programs with those of traditional market variables. We find that local income taxes and tax-equalization grants have important effects on local labor markets; regional development policy measures and geographical-mobility subsidies do not. Thus, recent efforts scaling back some of these programs may not materially alter the regional economy's performance. Wages and other traditional market variables are also often found to influence significantly local labor markets."  相似文献   
45.
ABSTRACT Casinos are often considered as a “growth pole” strategy to revitalize dilapidated regions. However, voters often reject casinos due to their perceived adverse impact on crime. Using a quasi-experimental design we analyze the impact of the casinos on crime spillover from Atlantic City to other localities in the region. We found that the level of crime in localities adjacent to Atlantic City and along the major nontoll routes to Philadelphia and New York City up to approximately 30 miles from Atlantic City rose significantly following the introduction of casinos. Crime levels are higher than they would have been in the absence of casinos.  相似文献   
46.
ABSTRACT. In a simple urban model, where the only spatial distinction made is between center and suburb, we introduce a uniform distribution of preferences for land. Under a logarithmic utility function, we examine how the location and consumption decisions of individuals differ in consequence of their different preferences for land. Comparative statics indicate that the qualitative response of the city at equilibrium to changes in per capita income and transportation cost is not affected by the introduction of such heterogeneity. Possible extensions are also briefly discussed.  相似文献   
47.
48.
This paper has two main objectives. First, we review and evaluate four different computational methods for measuring the “fractality” of cartographic lines: these are known as the structured walk, the equipaced polygon, the hybrid walk, and the cell count methods. Second, because previous research has restricted the focus of fractal measurement exercises to isolated physical entities, the subject of our empirical study concerns the urban area of Swindon, United Kingdom, that comprises a mosaic of contiguous land-use parcels. In technical terms, the results pinpoint some of the comparative strengths and weaknesses of the four methods, whilst our substantive conclusion is that fractal dimension appears to be a function of both scale and land-use type in our geographical study.  相似文献   
49.
An axiomatic approach to distance is developed which focuses on those behavioral concepts of distance related to movement in space. In particular, spatial movement by behaving units is postulated to involve a choice from among some set of abstract trips in space, and implicitly, to involve the minimization of some relevant notion of trip costs. In this context, the relevant behavioral notion of distance in space is taken to be the minimum-cost distance generated by this choice process. These trip-cost concepts extend the classical notions of paths, path lengths, and shortest paths in metric spaces. Hence many of the analytical results of the paper involve extensions of classical shortest-path distance properties to minimum-cost distances. In addition to these extensions, a characterization theorem is given which specifies the possible functional relationships between trip costs and their associated path lengths. These relationships include most functional forms which are commonly employed in the literature.  相似文献   
50.
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