全文获取类型
收费全文 | 6725篇 |
免费 | 517篇 |
国内免费 | 555篇 |
专业分类
测绘学 | 2890篇 |
大气科学 | 380篇 |
地球物理 | 717篇 |
地质学 | 1737篇 |
海洋学 | 302篇 |
天文学 | 14篇 |
综合类 | 904篇 |
自然地理 | 853篇 |
出版年
2024年 | 12篇 |
2023年 | 44篇 |
2022年 | 137篇 |
2021年 | 182篇 |
2020年 | 180篇 |
2019年 | 188篇 |
2018年 | 134篇 |
2017年 | 302篇 |
2016年 | 249篇 |
2015年 | 301篇 |
2014年 | 342篇 |
2013年 | 491篇 |
2012年 | 419篇 |
2011年 | 441篇 |
2010年 | 328篇 |
2009年 | 312篇 |
2008年 | 353篇 |
2007年 | 428篇 |
2006年 | 420篇 |
2005年 | 374篇 |
2004年 | 391篇 |
2003年 | 301篇 |
2002年 | 280篇 |
2001年 | 240篇 |
2000年 | 178篇 |
1999年 | 150篇 |
1998年 | 141篇 |
1997年 | 104篇 |
1996年 | 92篇 |
1995年 | 46篇 |
1994年 | 59篇 |
1993年 | 50篇 |
1992年 | 34篇 |
1991年 | 16篇 |
1990年 | 22篇 |
1989年 | 18篇 |
1988年 | 17篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有7797条查询结果,搜索用时 15 毫秒
21.
本文在解放军土地管理局研制的“军用土地管理信息系统”的基础上,从系统设计和应用的角度出发,明确了系统应包括的基本功能,提出了改进和完善系统的方法。 相似文献
22.
23.
Although the logistics industry provides critical services to all sectors of the economy, few studies exist in economic geography that examine and explain the organizational dynamics of this industry. This article highlights the significance of the logistics industry in contemporary industrialization and argues that an enriched understanding of the interaction between technology and space can be achieved by examining the evolution of an industry that plays a central role in the contemporary economy. We focus on dimensions that are identified as particularly important: organizational, geographic, and risk and security. 相似文献
24.
This study investigates the extent to which people's views on the causes and preventability of earthquake damage might be influenced by their degree of exposure to hazard as well as what information they have been given about the hazard. The results show that the provision of hazard zoning information influences judgements on preventability and causes of damage, but this effect depends on the degree of hazard faced by residents. In low hazard zones, information leads to the view that causes are manageable, whereas in high hazard zones information may induce a degree of fatalism. The use of public information in risk management needs to take into account the degree of risk faced by the recipients. 相似文献
25.
Spatial assessment and redesign of a groundwater quality monitoring network using entropy theory, Gaza Strip, Palestine 总被引:3,自引:0,他引:3
Using entropy theory, a methodology was developed for the evaluation and redesign of groundwater quality monitoring wells in the Gaza Strip in Palestine. Essential to the methodology is the development of a Transinformation Model (TM) which yields the amount of information transfer and the dependency between the wells as a function of distance. The TM parameters, such as the minimum transinformation and the range, were employed for evaluating the network which revealed that most of the distances between wells were less than the range. It also indicated that a high percentage of redundant information existed in the network. Therefore, the network was reduced by superimposing a square pattern over the monitored area and selecting one well per square block in a stratified pattern. The methodology was tested using the chloride data collected from 1972–2000 from 417 groundwater quality monitoring wells in the Gaza Strip. The number of the groundwater quality monitoring wells in the Gaza Strip was reduced by 53%, while there was 26% redundant information based on the minimum existing distance between wells. This methodology is meant to help monitor the groundwater quality (salinity) in the Gaza Strip. 相似文献
26.
互联网在方便人们交流、共享信息的同时,也带来了极大的安全问题.信息隐藏是解决信息安全的一种有效手段,研究采用LSB法实现重要目标遥感图像信息的隐藏,实验证明该方法可以有效地解决网上图像传输出现的安全问题. 相似文献
27.
28.
MODIS数据在广西生态环境监测及评价中的应用方法 总被引:8,自引:0,他引:8
利用MODIS数据广西遥感影像,用监督分类法做出了地物覆盖分类图,用主成分分析法做出了土壤侵蚀强度图和生态环境质量综合评价指数图。 相似文献
29.
VML在WebGIS图形显示中的应用研究 总被引:3,自引:0,他引:3
针对目前被动式WebGIS地图显示的局限,提出了引入VML的解决办法,使客户端容易实现矢量地图显示、地物动态变化显示、专题制图显示等,丰富了WebGIS的地图表现方式。 相似文献
30.
CHENChujiang LIDeren ZHUQing 《地球空间信息科学学报》2005,8(1):33-38
This paper presents the studies of the refining of IKONOS-2 RPC, the transform of the datum, the mode of the control point distribution and the method of IKONOS stereo triangulation, so that IKONOS imagery can be used to collect the precise geospatial data and produce the large scale map. The transform between the IKONOS-2 image space and the national coordinate system based on the RPC have been developed, and the results of block adjustment with various control schemes in a practical project near Himalayas have been examined and analysed. The encouraging results of high positioning accuracy have been obtained. 相似文献