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   3234篇
  免费   576篇
  国内免费   545篇
测绘学   134篇
大气科学   432篇
地球物理   1046篇
地质学   1616篇
海洋学   382篇
天文学   7篇
综合类   171篇
自然地理   567篇
  2024年   32篇
  2023年   88篇
  2022年   166篇
  2021年   178篇
  2020年   177篇
  2019年   186篇
  2018年   162篇
  2017年   143篇
  2016年   186篇
  2015年   146篇
  2014年   244篇
  2013年   263篇
  2012年   203篇
  2011年   204篇
  2010年   187篇
  2009年   188篇
  2008年   201篇
  2007年   172篇
  2006年   198篇
  2005年   132篇
  2004年   113篇
  2003年   95篇
  2002年   91篇
  2001年   79篇
  2000年   63篇
  1999年   63篇
  1998年   61篇
  1997年   35篇
  1996年   61篇
  1995年   59篇
  1994年   48篇
  1993年   39篇
  1992年   32篇
  1991年   20篇
  1990年   10篇
  1989年   7篇
  1988年   6篇
  1987年   3篇
  1986年   5篇
  1985年   3篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1978年   1篇
排序方式: 共有4355条查询结果,搜索用时 23 毫秒
81.
甘肃省东南部未来地震危险区的模式识别   总被引:1,自引:0,他引:1       下载免费PDF全文
在综合分析甘肃省东南部地震地质特征的基础上,利用模式识别方法判定未来地震危险区的可能位置.结果表明,本区易发生地震的地点与全新世断裂强烈活动段相吻合,从而提高了对未来地震危险区判定的可信度  相似文献   
82.
采用R值评分方法,对中国地震局地球物理研究所2001—2004年度划定的全国地震危险区进行了评估,2001—2004年度的R值分别为0.265、0.182、0.293、0.404。近两年的R值相对高些,为了排除随机成分,做了相应的随机预报试验检验,并对地震落入危险区的随机概率作了估计。结果表明,4个年度的R值明显高于随机预报,除2002年度外,地震随机落入危险区的概率很低,不到2%。这说明中国地震局地球物理研究所实际地震危险区划分取得了一定的效果,且逐年提高。  相似文献   
83.
高分辨率卫星影像已经在一些国家的民用领域得到应用。利用高分辨率卫星影像来收集地震损失评价所需要的各类城市信息不仅高效和有较好的时间分辨率,而且它可以减少以往所必需的大量的代价高昂且费力的城市调查。基于在印度城市台拉登所做的研究,讨论了如何利用高分辨率卫星影像进行城市特征识别的一些问题,同时也简单论述了利用GIS/RS软件综合所得的数据以便用于地震损失评价的方法。  相似文献   
84.
As one of the most powerful tools to reduce the earthquake loss, the Earthquake Disaster Management [EDM] and Insurance [EI] have been highlighted and have had a great progress in many countries in recent years. Earthquake disaster management includes a series of contents, such as earthquake hazard and risk analysis, vulnerability analysis of building and infrastructure, earthquake aware training, and building the emergency response system. EI, which has been included in EDM after this practice has been done for many years, include these contents: insurance model, financing. This paper presents the development of china in EDM and EI. The main contents include: (1) the statue and trend of earthquake disaster management and insurance in china; (2) the progresses and new methods about the seismic risk zonation and vulnerability analysis, and the future developing trend, the application of GIS in earthquake disaster assessment is introduced; (3) the way and illustration in building the earthquake disaster e  相似文献   
85.
21世纪中国地质灾害防治形势与减灾战略思考   总被引:9,自引:0,他引:9  
文章论述了21世纪中国地质灾害减灾面临的形势是既存在许多有利条件又存在多方面困难而面临严重挑战。提出21世纪地质灾害减灾战略:1.建立地质灾害防治安全维护体系;2.优先安排西部地区地质灾害防治工程,实施地质灾害风险管理;3.建立矿山地质灾害防治监督管理体系;4.城市地质灾害防治与土地利用相结合;5.加强我国地质环境监测与网站建设;6.针对地质灾害区域分布规律,采取分区减灾对策;7.加大地质灾害防治投入力度。  相似文献   
86.
建设用地地质灾害危险性评估中几个问题的思考   总被引:7,自引:3,他引:7  
结合工作实践,就建设用地地质灾害危险性评估及其成果审查工作中经常遇到的5个问题——评估灾害类型的确定原则,评估区环境条件分析深度的把握,现状、预测及综合地质灾害危险性评估内容的侧重点,土地适宜性评价的依据以及优秀评估成果的判定标准,提出了个人的理解和认识。供从事类似工作的同志参考。  相似文献   
87.
I.Y. Malchikova 《冰川冻土》2004,26(Z1):206-209
The development of North Transbaikalye mineral resources (e. g. the Chiney deposit of iron titanium-vanadium-magnetite ores and Udokan copper deposits) is impossible without the establishment of industrial and transport infrastructure, one component of which are linear engineering constructions (drive railways, by-line auto roads, platform passages, protecting constructions, and others). However,on condition of spreading permafrost rocks this is conjugated with certain ecological risk just as from the transport network objects so for the objects themselves. A special attention is paid in the paper to considering of problems of projecting and constructing railways on the Udokan ridge.  相似文献   
88.
Perceptions of hazard and risk on Santorini   总被引:1,自引:0,他引:1  
Santorini, Greece is a major explosive volcano. The Santorini volcanic complex is composed of two active volcanoes—Nea Kameni and Mt. Columbo. Holocene eruptions have generated a variety of processes and deposits and eruption mechanisms pose significant hazards of various types. It has been recognized that, for major European volcanoes, few studies have focused on the social aspects of volcanic activity and little work has been conducted on public perceptions of hazard, risk and vulnerability. Such assessments are an important element of establishing public education programmes and developing volcano disaster management plans. We investigate perceptions of volcanic hazards on Santorini. We find that most residents know that Nea Kameni is active, but only 60% know that Mt. Columbo is active. Forty percent of residents fear that negative impacts on tourism will have the greatest effect on their community. In the event of an eruption, 43% of residents would try to evacuate the island by plane/ferry. Residents aged >50 have retained a memory of the effects of the last eruption at the island, whereas younger residents have no such knowledge. We find that dignitaries and municipal officers (those responsible for planning and managing disaster response) are informed about the history, hazards and effects of the volcanoes. However, there is no “emergency plan” for the island and there is confusion between various departments (Civil Defense, Fire, Police, etc.) about the emergency decision-making process. The resident population of Santorini is at high risk from the hazards associated with a future eruption.  相似文献   
89.
Although seismic isolation rubber bearings in bridges and buildings have proven to be a very effective passive method for reducing earthquake‐induced forces, a detailed mechanical modeling of the rubber that is used in bearings under large strains has not been established. Therefore, a 3D model of failure behavior and the design criteria for the safety evaluation of seismic isolation bearings have not yet been developed. This paper presents: (1) correlation‐based template‐matching algorithms to measure large strain fields of continua; (2) a failure criterion for rubber; and (3) the design criteria for the safety evaluation of laminated algorithms, data‐validation algorithms were developed and implemented to eliminate possible unrealistic displacement vectors present in the measured displacement field. The algorithms were successfully employed in the strain field measurement of LRB and rubber materials that are subjected to failure. The measured local strains for rubber material at failure were used to develop a failure criterion for rubber. The validity of the proposed criterion was evaluated by applying it to the LRB; the criterion was introduced into a 3D finite element model of LRB, compared with the experimental results of bearings failure, and verified. Finally, design criteria are proposed for LRB for the safety evaluation. Copyright © 2003 John Wiley & Sons, Ltd.  相似文献   
90.
洪水保险的理论分析与研究   总被引:4,自引:0,他引:4       下载免费PDF全文
简述了目前一些国家的洪水保险的现状,综合应用了经济学、保险学、系统工程等理论和知识,对洪水保险问题进行了深入分析和研究,揭示了洪水保险的内在性质和规律,建立了洪水保险的效用模型。结合我国的国情,对我国实施洪水保险提出了建议。  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