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   41889篇
  免费   1634篇
  2020年   539篇
  2019年   831篇
  2018年   956篇
  2017年   1148篇
  2016年   1226篇
  2015年   929篇
  2014年   906篇
  2013年   14103篇
  2012年   1058篇
  2011年   1079篇
  2010年   1080篇
  2009年   1071篇
  2008年   1015篇
  2007年   931篇
  2006年   828篇
  2005年   577篇
  2004年   571篇
  2003年   530篇
  2002年   511篇
  2001年   536篇
  2000年   464篇
  1999年   522篇
  1998年   465篇
  1997年   425篇
  1996年   409篇
  1995年   414篇
  1994年   362篇
  1993年   411篇
  1992年   396篇
  1991年   298篇
  1990年   293篇
  1989年   315篇
  1988年   309篇
  1987年   333篇
  1986年   309篇
  1985年   419篇
  1984年   448篇
  1983年   456篇
  1982年   402篇
  1981年   391篇
  1980年   424篇
  1979年   420篇
  1978年   414篇
  1977年   430篇
  1976年   379篇
  1975年   382篇
  1974年   286篇
  1973年   267篇
  1972年   249篇
  1970年   222篇
排序方式: 共有10000条查询结果,搜索用时 468 毫秒
141.
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   
142.
ABSTRACT. This paper uses a large data base to study metropolitan labor demand functions. The data are disaggregated by two-digit SICs in manufacturing for SMS As, and are corrected for changing SMSA boundaries. Labor demand elasticities are estimated for factor and commodity prices, transportation costs, state and local taxes and expenditures, and production-function shifters. Estimates from different years allow one to test Le Chatelier's principle in the context of interregional change.  相似文献   
143.
ABSTRACT. This paper examines the RAS, Mc Menamin and Haring, and Lagrange-multiplier update methods in the context of the dual accounting system of the rectangular input-output model. The motivation was to determine if the additional information contained in the dual system is exploitable, while maintaining the integrity of the rectangular structure with all its advantages. Tests were conducted on the performance of the various algorithms for a derivative Leontief model relative to their performance on the rectangular structure. The results obtained for rectangular tables were generally better than those obtained for the more conventional Leontief ones.  相似文献   
144.
145.
Mapping population data from zone centroid locations   总被引:1,自引:0,他引:1  
The author describes the difficulties associated with the use of maps to represent census data. "A review of the problems associated with population mapping is followed by a discussion of [an alternative method known as] a raster method for handling census data, based on population-weighted centroids, and its implications for GIS "[geographic information systems]." The geographical scope is worldwide, with an example provided using data for Wales.  相似文献   
146.
Reviews     
Babi and Baha'i Religions: From Messianic Shi'ism to a World Religion, by Peter Smith, Cambridge University Press, London, New York, New Rochelle, Melbourne, Sydney 1987, pp.xiv, 243.

Panj Vaqf‐namah, by Mahmud Afshar Yazdi, (Five Endowment Deeds), Tehran Foundation for Mahmud Afshar Yazdi's Endowments, 1363/1984. Iraj Afshar and Karim Isfahaniyan, eds., Namvarah‐yi Doktor Mahmūd Afshar Yazdi (Mahmud Afshar Yazdi's Festschrift), 4 vols., Tehran: Foundation for Mahmud Afshar Yazdi's Endowments, 1364/1985–1367/1988.

Bulles et Sceaux sassanides de diverses collections, by Philippe Gignoux and Rika Gysclen, Paris: Sludia Iranica, Cahier 4, Association Pour l'avancemeni des études iraniennes, 1987, 306 pp, 23 plates.

Iran and Iraq at War , by Shahram Chubin and Charles Tripp, Boulder, Colorado: Westview Press, 1988.

The Tragedy of Sohrab and Rostam, from the Persian National Epic, the Shahnameh of Abol‐Qascm Ferdowsi, translated by Jerome W. Clinton, Seattle: The University of Washington Press, 1988, xxv + 190 pages, $25.00 cloth $12.50 paper.

Persian Carpets , by Michael Craig Hillmann, Austin: University of Texas Press, 1984, 98 pp. index to p. 112.

Resurrection and Renewal: The Making of the Babi Movement in Iran, 1844–1850, Abbas Amanat, Ithaca & London: Cornell University Press, 1989, pp. xv.+ 461, no price indicated.

Iran min al‐Dakhil, (Iran From Within), by Fahmi Huwaydi, Cairo: Markaz al‐Ahram li al‐tarjuma wa al‐nashr, 1987, 405 pp.

Woven From the Soul, Spun from the Heart: Textile Arts of Safavid and Qajar Iran, 16lh‐19lh Centuries , edited by Carol Bier, Washington, DC: The Textile Museum, 1987.

Summon Up Remembrance, by Marzich Gail, Oxford: George Ronald Books, 1987, 295 pp., appendix, bibliography, $14.95.

Iran and The United States, A Cold War Case Study, by Richard W. Cottam, Pittsburgh: University of Pittsburgh Press, 1988. $12.95 pb.  相似文献   

147.
148.
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   
149.
150.
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