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   6707篇
  免费   336篇
  2023年   57篇
  2020年   144篇
  2019年   133篇
  2018年   271篇
  2017年   290篇
  2016年   273篇
  2015年   195篇
  2014年   167篇
  2013年   1798篇
  2012年   166篇
  2011年   177篇
  2010年   178篇
  2009年   161篇
  2008年   174篇
  2007年   127篇
  2006年   120篇
  2005年   90篇
  2004年   81篇
  2003年   77篇
  2002年   80篇
  2001年   82篇
  2000年   83篇
  1999年   96篇
  1998年   81篇
  1997年   59篇
  1996年   67篇
  1995年   62篇
  1994年   58篇
  1993年   71篇
  1992年   62篇
  1991年   43篇
  1990年   43篇
  1989年   64篇
  1988年   51篇
  1987年   60篇
  1986年   59篇
  1985年   79篇
  1984年   96篇
  1983年   83篇
  1982年   69篇
  1981年   76篇
  1980年   77篇
  1979年   71篇
  1978年   71篇
  1977年   57篇
  1976年   75篇
  1975年   77篇
  1974年   49篇
  1973年   39篇
  1972年   36篇
排序方式: 共有7043条查询结果,搜索用时 15 毫秒
81.
Sutton and Lawless review a selection of the prolific literature on the Maghreb's human geography published from the late 1970s onward. The pedigree of the discipline in Maghreb was established by several notable geographers who lived, researched, and wrote there. Augustin Bernard's writings on rural settlement, his atlas, and study of Algeria are still cited. Jean Despois's regional study with Raynal and his work on Tunisia, together with the detailed rural research of Jean Poncet, provides a particularly rich coverage for that country. Jean Dresch's early work on Morocco exemplified an early critique of the contemporaneous uncritical colonial human geography. The Sahara's fascination also inspired pioneering studies by Robert Capot-Rey. The work of these notables and others provided a solid background of geographical literature on the Maghreb to be supplemented, criticized, and challenged by more recent researchers, sometimes pupils of the above individuals, and increasingly North African by birth. The tradition of general texts on the Maghreb has continued, though increasingly with systematic approaches replacing regional appraisals. The geography of the decolonization of the Maghreb by Isnard has been replaced by a study summarizing recent collaborative work by a team of French geographers. The Saharan extensions of the Maghreb states have often been linked in general works, sometimes being juxtaposed against the Maghreb as in the essays offered to Jean Despois. Lawless and Findlay's collaborative study juxtaposes geographical studies of each country's economic development with political scientists' evaluations of their sociopolitical development. This review limits itself largely to geographers and geographical journals, only occasionally including significant works from other subject areas, and to 1977-1978 publications, with a few notable exceptions. The spatial juxtaposition of contrasting approaches to economic development, liberal market economy approaches by Tunisia and Morocco arguably leading to dependency, and centrally-planned strategies by Algeria and Libya resulting in bureaucratic constraints serves to offer the Maghreb as a pertinent case-study region for the applied geographer of developing countries.  相似文献   
82.
83.
84.
85.
The p-median problem is a powerful tool in analyzing facility location options when the goal of the location scheme is to minimize the average distance that demand must traverse to reach its nearest facility. It may be used to determine the number of facilities to site, as well as the actual facility locations. Demand data are frequently aggregated in p-median location problems to reduce the computational complexity of the problem. Demand data aggregation, however, results in the loss of locational information. This loss may lead to suboptimal facility location configurations (optimality errors) and inaccurate measures of the resulting travel distances (cost errors). Hillsman and Rhoda (1978) have identified three error components: Source A, B, and C errors, which may result from demand data aggregation. In this article, a method to measure weighted travel distances in p-median problems which eliminates Source A and B errors is proposed. Test problem results indicate that the proposed measurement scheme yields solutions with lower optimality and cost errors than does the traditional distance measurement scheme.  相似文献   
86.
87.
88.
89.
This paper is a statistical and geological study of the results of analysis of flint from British and West European flint mines, carried out by emission and atomic absorption spectroscopy. Groups of flint specimens were studied from each geographically separate flint mining area. Flints were analysed for a group of easily measured trace elements shown by previous work to be generally present. The ratios between the trace elements form a consistent pattern for each flint mine and statistically valid differences of pattern can be recognized between different flint mines. A geological investigation shows that the measured trace elements may be derived from clay minerals and explains geographical and statistical variation in the composition of flint in terms of its mode of origin in the chalk. An advanced statistical technique allows individual flint specimens of unknown origin to be attributed by their composition to one or other of the identified flint sources. The archaeological implications of this study are discussed.  相似文献   
90.
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