全文获取类型
收费全文 | 448篇 |
免费 | 48篇 |
国内免费 | 17篇 |
专业分类
测绘学 | 49篇 |
大气科学 | 19篇 |
地球物理 | 148篇 |
地质学 | 70篇 |
海洋学 | 7篇 |
天文学 | 168篇 |
综合类 | 12篇 |
自然地理 | 40篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 3篇 |
2021年 | 4篇 |
2020年 | 5篇 |
2019年 | 11篇 |
2018年 | 8篇 |
2017年 | 7篇 |
2016年 | 6篇 |
2015年 | 8篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 10篇 |
2011年 | 22篇 |
2010年 | 24篇 |
2009年 | 44篇 |
2008年 | 32篇 |
2007年 | 20篇 |
2006年 | 22篇 |
2005年 | 18篇 |
2004年 | 26篇 |
2003年 | 17篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 21篇 |
1999年 | 40篇 |
1998年 | 31篇 |
1997年 | 15篇 |
1996年 | 11篇 |
1995年 | 7篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 7篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 1篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有513条查询结果,搜索用时 29 毫秒
71.
72.
西方国家办公空间研究综述 总被引:2,自引:0,他引:2
文章分别从区位论、城市空间结构理论等角度入手,总结了西方早期上述理论体系中办公空间研究的相关内容,并从办公空间的区位特征、集聚与扩散及其空间结构形成机制等方面对西方战后在办公空间方面的研究进展进行了综述,还对西方办公空间的研究方法进行了总结,最后结合我国的实际情况对西方的研究进行了述评,以期为我国相同领域研究的开展提供一点启示。 相似文献
73.
锑矿化集中于喜马拉雅期石英斑岩内接触带,存在矿源层形成、充分分异及近地表成矿三个阶段。可作为滇西碱性岩锡矿床典型。 相似文献
74.
Bin Jiang 《International journal of geographical information science》2013,27(7):823-837
A city can be topologically represented as a connectivity graph, consisting of nodes representing individual spaces and links if the corresponding spaces are intersected. It turns out in the space syntax literature that some defined topological metrics can capture human movement rates in individual spaces. In other words, the topological metrics are significantly correlated to human movement rates, and individual spaces can be ranked by the metrics for predicting human movement. However, this correlation has never been well justified. In this paper, we study the same issue by applying the weighted PageRank algorithm to the connectivity graph or space–space topology for ranking the individual spaces, and find surprisingly that: (1) the PageRank scores are better correlated to human movement rates than the space syntax metrics, and (2) the underlying space–space topology demonstrates small world and scale free properties. The findings provide a novel justification as to why space syntax, or topological analysis in general, can be used to predict human movement. We further conjecture that this kind of analysis is no more than predicting a drunkard's walking on a small world and scale free network. 相似文献
75.
Ahmed Mahmood 《国际地球制图》2013,28(2):91-101
In the case of a major disaster, information derived from satellite observation is not only highly useful, it may at times be indispensable because of the damage caused by the disaster to ground infrastructure. The International Charter ‘Space and Major Disasters’ (‘the Charter’) has been one of the primary sources of satellite data for the past 11 years to cover events like floods, fires, tsunamis, ocean storms, earthquakes, volcanic eruptions and oil spills. With the growing membership of the Charter, an increasingly large number of sensors are now available, which can be planned with the required temporal frequency and spectral range to cover a disaster event. Some of the type Charter activation cases are reported in this article to demonstrate the innovative use of multi-satellite imagery for disaster response. 相似文献
76.
Space,time, and situational awareness in natural hazards: a case study of Hurricane Sandy with social media data 总被引:1,自引:0,他引:1
Zheye Wang 《制图学和地理信息科学》2013,40(4):334-346
ABSTRACTVarious methods have been developed to investigate the geospatial information, temporal component, and message content in disaster-related social media data to enrich human-centric information for situational awareness. However, few studies have simultaneously analyzed these three dimensions (i.e. space, time, and content). With an attempt to bring a space–time perspective into situational awareness, this study develops a novel approach to integrate space, time, and content dimensions in social media data and enable a space–time analysis of detailed social responses to a natural disaster. Using Markov transition probability matrix and location quotient, we analyzed the Hurricane Sandy tweets in New York City and explored how people’s conversational topics changed across space and over time. Our approach offers potential to facilitate efficient policy/decision-making and rapid response in mitigations of damages caused by natural disasters. 相似文献
77.
78.
CSAMT法在四台矿402盘区陷落柱构造探测中的应用 总被引:10,自引:7,他引:10
可控源音频大地电磁法应用于寻找煤田落陷落柱构造,乃是个新课题。通过对大同矿务局四台矿402盘区的野外实际应用,发现了两个陷柱落构造,与实际资料基本吻合。 相似文献
79.
Trajectory Analysis and Design for A Jupiter Exploration Mission 总被引:1,自引:0,他引:1
The trajectory design for a Jupiter exploration mission is investigated in this paper. The differences between the Jupiter exploration trajectory and the Mars or Venus exploration trajectory are mainly concerned about. Firstly, the selection of the Jupiter-centered orbit is analyzed based on the Galileo Jupiter mission. As for the Earth-Jupiter transfer orbit, the fuel consumption of the direct transfer is too large. So the energy-saving technologies such as the planetary gravity assist should be used for the trajectory to the Jupiter. The different sequences of planetary gravity assists are examined by applying the Particle Swarm Optimization (PSO). According to the searched result, the Venus-Earth-Earth sequence (VEEGA) is the most effective one for the Jupiter mission. During the Jupiter mission, the spacecraft will pass though the main asteroid belt between the orbits of Mars and Jupiter, and may encounter multiple asteroids. Therefore the Jupiter mission is able to combine with the main-belt asteroid flyby mission. The design method of the intermediate asteroid flyby trajectory is also considered. At last, an entire trajectory for the Jupiter mission launched in 2023 is presented. 相似文献
80.
From the point of view of the non-parametric statistics, a general estimation method of the accuracy and con?dence interval of preliminary orbit determination is proposed for the occasion without any other information but observational data. Based on the bootstrap method, the estimation relies only on the observational data and does not require the precise orbit determination as a reference, or the assumption of normal distribution of observational errors. Numerical experiments show that this method is very simple in implementa- tion, and may serve as an easy accuracy evaluation for the preliminary orbit determination and for the follow-up employments. 相似文献