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   822篇
  免费   169篇
  国内免费   190篇
测绘学   41篇
大气科学   62篇
地球物理   70篇
地质学   679篇
海洋学   60篇
天文学   5篇
综合类   63篇
自然地理   201篇
  2024年   6篇
  2023年   11篇
  2022年   36篇
  2021年   38篇
  2020年   42篇
  2019年   31篇
  2018年   23篇
  2017年   29篇
  2016年   58篇
  2015年   34篇
  2014年   52篇
  2013年   65篇
  2012年   47篇
  2011年   58篇
  2010年   47篇
  2009年   47篇
  2008年   43篇
  2007年   51篇
  2006年   40篇
  2005年   58篇
  2004年   41篇
  2003年   54篇
  2002年   68篇
  2001年   38篇
  2000年   34篇
  1999年   34篇
  1998年   22篇
  1997年   13篇
  1996年   15篇
  1995年   9篇
  1994年   6篇
  1993年   4篇
  1992年   6篇
  1991年   4篇
  1990年   1篇
  1989年   2篇
  1988年   5篇
  1987年   2篇
  1986年   1篇
  1984年   3篇
  1983年   2篇
  1982年   1篇
排序方式: 共有1181条查询结果,搜索用时 171 毫秒
111.
新构造运动对冲积河流影响研究的回顾与展望   总被引:1,自引:0,他引:1  
研究新构造运动本身及其对冲积河流的影响,可以深化地貌学理论、沉积旋回复杂性假设等的认识,也与实际应用密切相关。将活动构造作为新构造运动的一个组成部分,回顾了新构造运动对冲积河流影响,并提及新构造运动本身的研究进展。控制流域水系格局及河流走向的研究,侧重地质学解释;新构造运动应力场的研究,深化了新构造运动机理及驱动力的探讨。三类基本缓慢新构造运动影响水系发育、河床演变、河型变化及河道冲淤,表现出复杂性、层次性、敏感性和先兆性;文章兼及河流侵蚀作用形成"新构造"的研究进展,回顾了物理模型实验研究成就及数学模拟研究端倪。进而指出:应注重该学科的交叉、渗透、综合研究与新构造快速运动方式对冲积河流影响的研究,定期进行新构造运动活跃区的升降速率、河床演变与泥沙输移的观测,进一步推进物理模型实验与数学模拟研究,并加强研究力量的协作与融合。  相似文献   
112.
Two approaches of statistical downscaling were applied to indices of temperature extremes based on percentiles of daily maximum and minimum temperature observations at Beijing station in summer during 1960-2008. One was to downscale daily maximum and minimum temperatures by using EOF analysis and stepwise linear regression at first, then to calculate the indices of extremes; the other was to directly downscale the percentile-based indices by using seasonal large-scale temperature and geo-potential height records. The cross-validation results showed that the latter approach has a better performance than the former. Then, the latter approach was applied to 48 meteorological stations in northern China. The cross-validation results for all 48 stations showed close correlation between the percentile-based indices and the seasonal large-scale variables. Finally, future scenarios of indices of temperature extremes in northern China were projected by applying the statistical downscaling to Hadley Centre Coupled Model Version 3 (HadCM3) simulations under the Representative Concentration Pathways 4.5 (RCP 4.5) scenario of the Fifth Coupled Model Inter-comparison Project (CMIP5). The results showed that the 90th percentile of daily maximum temperatures will increase by about 1.5℃, and the 10th of daily minimum temperatures will increase by about 2℃ during the period 2011-35 relative to 1980-99.  相似文献   
113.
胶南市七宝山地区发现了以银铅为主的多金属矿 ,矿石中有益组分以银铅为主 ,伴生有萤石、铜及少量金 ,其找矿标志是硅化构造破碎带、石英脉、萤石石英脉等。找矿方向应集中于山周断裂两侧和燕山晚期伟德山超单元之中。该区具有较好的找矿前景  相似文献   
114.
Results of a survey of instrumentation and detector systems, either currently deployed or planned for use at telescopes larger than 3.5 m, in ground based observatories world-wide, are presented. This survey revealed a number of instrumentation design trends at optical, near, and mid-infrared wavelengths. Some of the most prominent trends include the development of vastly larger optical detector systems (> 109 pixels) than anything built to date, and the frequent use of mosaics of near-infrared detectors – something that was quite rare only a decade ago in astronomy. Some future science applications for detectors are then explored, in an attempt to build a bridge between current detectors and what will be needed to support the research ambitions of astronomers in the future.  相似文献   
115.
BOOK REVIEWS     
Books reviewed in this article: Aerial Photography and Remote Sensing Aerial photography and image interpretation for Resource Management . DAVID P. PAINE . Analytical Models and Techniques Spatial Processes Models and Applications A. D. CLIFF AND J. K. ORD Quantitative and Statistical Approaches to Geography: A Practical Manual JOHN A. MATTHEWS . Cartography and Maps Map Data Processing . HERBERT FREEMAN AND GOFFREDO G. PIERONI , eds. Computer-assisted Cartography: Principles and Prospects, 1982 . MARK S. MONMONIER . Cultural Navajo Architecture: Forms, History, Distributions . STEPHEN C. JETT AND VIRGINIA E . SPENCER . Rational Landscapes and Humanistic Geography . EDWARD RELPH . Economic The Structure and Control of a State Economy . W. L. L'ESPERANCE . Economic Geography . JAMES O. WHEELER AND PETER O. MULLER . The Myth of the Family Farm: Agribusiness Dominance of U.S. Agriculture . INGOLF VOCELER . Libya: The Experience of Oil . J. A. ALLEN . Geography of Public Finance, Welfare Under Fiscal Federalism and local Government Finance . ROBERT BENNETT . Environmental Management, Resources, and Systems Mountains and Man . LARRY W. PRICE . Environmental Geology . DONALD R. COATES . An Introduction to Environmental Systems . G. H. DURY . The Environment: Chinese and American Views . Edited by LAURENCE J. C. MA AND ALLEN G. NOBLE . Land Use in America . RICHARD H. JACKSON . Medical Conceptual and Methodological Issues in Medical Geography . MELINDA S. MEADE (ed.). Philosophy and Geographic Thought Birds in Egg/Eggs in Bird . GUNNAR OLSSON . PhysicaI Climatology: Selected Applications . J. E. OLIVER . Geomorphological Techniques . ANDREW GOUDIE (ed.). Political Politics, Geography and Behaviour . RICHARD MUIR AND RONAN PADDISON . The State of the World Atlas . MICHAEL KIDRON AND RONALD SECAL . Population The Population of the South . DUDLEY L. POSTON , JR . AND ROBERT H. WELLER , eds. Regional Latin America: Economic Development and Regional Differentiation . ARTHUR MORRIS . Developing the Amazon . EMILIO F. MORAN . Western Europe: A Systematic Human Geography . BRIAN W. ILBERY . Settlement Systems in Sparsely Settled Regions: The United States and Australia . RICHARD E. LONSDALEAND JOHN H. HOLMES , eds. African Perspectives: The Economic Geography of Nine African States . HARM DE BUJ AND ESMOND MARTIN , eds. Rural Nonmetropolitan America in Transition . AMOS H. HAWLEY AND SARA MILLS MAZIE , eds. Social Crime and Environment . R. NORMAN DAVIDSON . The Ghetto: Readings with Interpretations . JOE T. DARDEN , ed. Urban Urban Problems and Planning in the Developed World . MICHAEL PACIONE (ed.) Problems and Planning in Third World Cities . Edited by MICHAEL PACIONE . The City in West Europe . D. BURTENSHAW , M. BATEMAN , AND C. J. ASHWORTH .  相似文献   
116.
SOFTWARE REVIEWS     
software reviews are in this article MACATLAS . Number Cruncher Statistical System (NCSS) TRANSPRO FIRE-ROUTER  相似文献   
117.
BOOK REVIEWS     
Book Reviewed in this article: Marine Resources of Kuwait: Their Role in the Development of Non-oil Resources . Fatimah H. Y. al -Abdul -Razzak Recollections of a Revolution: Geography as Spatial Science . Mark Billinge , Derek Gregory and Ron Martin Entre l'Eden et l'Utopie . Luc Bureau Developments in Political Geography . M. A. Busteed The Elements of Graphing Data . William S. Cleveland Rural Resource Management . Paul J. Cloke and Chris C. Park Third World Atlas . Ben Crow and Alan Thomas Exploitation, Conservation, Preservation: A Geographic Perspective on Natural Resource Use . Susan L. Cutter , Hilary Lambert Renwick, and William H. Renwick . Wine Regions of the Southern Hemisphere . Harm Jan de Blij Regional Development: Problems and Policies in Eastern and Western Europe . George Demko The Geographer at Work . Peter R. Gould Change in the Amazon Basin . John Hemming Geography Since the Second World War . R. J. Johnston and P. Claval Urbanization in China: Town and Countryside in a Developing Economy 1949–2000 A.D. , R. J. R. Kirkby Transport and Communications for Pacific Microstates: Issues in Organisation and Management . Christopher C. Kissling Fluvial Forms and Processes . David Knighton The Urban Millennium . Josef W. Konvitz Technological Transition in Cartography . Mark Stephen Monmonier Field Guide to Soils and the Environment: Applications of Soil Surveys . Gerald W. Olson Northern Australia: The Arenas of Life and Ecosystems on Half a Continent . Don Parkes A Killing Rain: The Global Threat of Acid Rain . Thomas Pawlick From the Family Farm to Agribusiness: The Irrigation Crusade in California and the West, 1850–1931 . Donald J. Pisani Hybrid Maize Diffusion in Kenya . Franz -Michael Rundquist Warning and Response to the Mount St. Helens Eruption . Thomas F. Saarinen and James L. Sell Coastal Geomorphology in Australia . B. G. Thom Tropical Rain Forests of the Far East , 2nd ed . T. C. Whitmore The Dark Side of the Earth . Robert Muir Wood Categorical Data Analysis for Geographers and Environmental Scientists , Neil Wrigley  相似文献   
118.
江西金山金矿田东蒋金矿床地质特征及找矿远景   总被引:3,自引:0,他引:3  
林忠良 《矿产与地质》2004,18(6):567-570
阐述了东蒋金矿床的成矿地质背景,通过对该金矿区地质特征的分析和总结,认为东蒋韧性剪切带为一卓具规模的控矿、容矿构造,其具有构造岩分带、蚀变分带及金矿化强度分带“三位一体”的规律性分布特点。指出该区业已发现韧性剪切带中的似层状金矿体和陡倾斜断裂带(F1)中的脉状金矿体,而该带目前无矿的东段分布有物探激电、航磁、重力异常及化探异常,这些都显示该区尚具有良好的找矿前景。  相似文献   
119.
巴南区地热资源丰富,热储总存量为3.105×1015KJ,热流体储存总量为6.855×108m3。经30多年的开发利用,已初步形成了以东温泉、南温泉、桥口坝温泉为核心的温泉旅游开发格局,主要用于温泉房地产开发、风景区、温泉旅游、康乐疗养休闲、商务会展等。为提升开发利用水平,巴南区地热水资源开发要以市场为导向,以效益为目标,突出重点、打造精品、强化特色、完善配套,建设特色温泉产业。  相似文献   
120.
中国城市群形成发育的政策影响过程与实施效果评价   总被引:6,自引:1,他引:5  
方创琳 《地理科学》2012,(3):257-264
中国城市群是中国未来经济发展格局中最具活力和潜力的核心地区,城市群的真正形成与发育始于20世纪80年代的改革开放初期,历经80年代的发育萌芽阶段、90年代快速成长阶段和21世纪前10 a的持续发展阶段,共三大阶段。城市群形成发育带有强烈的政府主导性,主要是国家及地方宏观调控政策和区域发展政策发挥作用的结果,体现在国家宏观调控政策的导向性和重点区域发展政策的倾向性两大方面。具体表现为,"六五"计划提出地区域协作和经济区政策开启了中国城市群建设的序幕,"七五"计划提出地三级经济区网络政策搭建了中国城市群建设的初步框架"八五"计划提出地横向联合与城乡统筹政策注入了中国城市群建设的一体化内容"九五"计划提出地区域协调发展政策推动了中国中西部地区城市群的形成发育"十五"计划实施地城镇化战略指明了中国城市群建设的基本方向"十一五"规划首次把城市群作为推进城镇化的主体空间形态,奠定了中国城市群建设的空间格局。与此同时,针对处在不同地区、不同类型和不同发育程度的城市群,国家相继因地制宜地实施了无数项差异化扶持政策,这些政策有力地推动着中国城市群朝着健康稳定的方向持续发展。  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