全文获取类型
收费全文 | 323篇 |
免费 | 18篇 |
国内免费 | 22篇 |
专业分类
测绘学 | 94篇 |
大气科学 | 48篇 |
地球物理 | 82篇 |
地质学 | 27篇 |
海洋学 | 58篇 |
天文学 | 7篇 |
综合类 | 26篇 |
自然地理 | 21篇 |
出版年
2023年 | 2篇 |
2022年 | 9篇 |
2021年 | 10篇 |
2020年 | 14篇 |
2019年 | 17篇 |
2018年 | 5篇 |
2017年 | 16篇 |
2016年 | 14篇 |
2015年 | 6篇 |
2014年 | 14篇 |
2013年 | 29篇 |
2012年 | 17篇 |
2011年 | 15篇 |
2010年 | 21篇 |
2009年 | 16篇 |
2008年 | 19篇 |
2007年 | 26篇 |
2006年 | 22篇 |
2005年 | 14篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 10篇 |
2001年 | 3篇 |
2000年 | 12篇 |
1999年 | 6篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1982年 | 1篇 |
排序方式: 共有363条查询结果,搜索用时 15 毫秒
61.
62.
电视测井中的图象处理问题 总被引:5,自引:3,他引:2
电视测井采集到的原始视频图象经过几何空间变换,图像象素重采样,最终生成可供地质分析解释的井壁表面图象文件。此外,必须动态识别指北针的图像以确定井下探头的方位,并以识别的北方位为起点守成图象的几何空间变换。基于井场施工效率和井下探头的安全原因,探头井中以4cm/s左右的速度下落,图像处理过程必须与探的落保持同步,因而还具有一定程度的实时性要求。 相似文献
63.
Andrew Curtis Jayakrishnan Ajayakumar Eric Jefferis Susanne Mitchell 《International journal of geographical information science》2019,33(6):1224-1250
ABSTRACTThe importance of including a contextual underpinning to the spatial analysis of social data is gaining traction in the spatial science community. The challenge, though, is how to capture these data in a rigorous manner that is translational. One method that has shown promise in achieving this aim is the spatial video geonarrative (SVG), and in this paper we pose questions that advance the science of geonarratives through a case study of criminal ex-offenders. Eleven ex-offenders provided sketch maps and SVGs identifying high-crime areas of their community. Wordmapper software was used to map and classify the SVG content; its spatial filter extension was used for hot spot mapping with statistical significance tested using Monte Carlo simulations. Then, each subject’s sketch map and SVG were compared. Results reveal that SVGs consistently produce finer spatial-scale data and more locations of relevance than the sketch maps. SVGs also provide explanation of spatial-temporal processes and causal mechanisms linked to specific places, which are not evident in the sketch maps. SVG can be a rigorous translational method for collecting data on the geographic context of many phenomena. Therefore, this paper makes an important advance in understanding how environmentally immersive methods contribute to the understanding of geographic context. 相似文献
64.
This article introduces a software package named GeoSurveillance that combines spatial statistical techniques and GIS routines to perform tests for the detection and monitoring of spatial
clustering. GeoSurveillance provides both retrospective and prospective tests. While retrospective tests are applied to spatial data collected for a
particular point in time, prospective tests attempt to incorporate the dynamic nature of spatial patterns via analyzing time-series
data to detect emergent clusters as quickly as possible. This article will outline the structure of GeoSurveillance as well as describe the statistical cluster detection methods implemented in the software. It concludes with an illustration
of the use of the software to analyze the spatial pattern of low birth weights in Los Angeles County, California.
相似文献
65.
66.
67.
Yizhao Gao Anand Padmanabhan Junjun Yin Guofeng Cao 《International journal of geographical information science》2018,32(3):425-449
Tracking spatial and temporal trends of events (e.g. disease outbreaks and natural disasters) is important for situation awareness and timely response. Social media, with increasing popularity, provide an effective way to collect event-related data from massive populations and thus a significant opportunity to dynamically monitor events as they emerge and evolve. While existing research has demonstrated the value of social media as sensors in event detection, estimating potential time spans and influenced areas of an event from social media remains challenging. Challenges include the unstable volumes of available data, the spatial heterogeneity of event activities and social media data, and the data sparsity. This paper describes a systematic approach to detecting potential spatiotemporal patterns of events by resolving these challenges through several interrelated strategies: using kernel density estimation for smoothed social media intensity surfaces; utilizing event-unrelated social media posts to help map relative event prevalence; and normalizing event indicators based on historical fluctuation. This approach generates event indicator maps and significance maps explaining spatiotemporal variations of event prevalence to identify space-time regions with potentially abnormal event activities. The approach has been applied to detect influenza activity patterns in the conterminous US using Twitter data. A set of experiments demonstrated that our approach produces high-resolution influenza activity maps that could be explained by available ground truth data. 相似文献
68.
During the April-June raining season,warm-sector heavy rainfall(WR) and frontal heavy rainfall(FR) often occur in the south of China,causing natural disasters.In this study,the microphysical characteristics of WR and FR events from 2016 to 2022 are analyzed by using 2-dimensional video disdrometer(2DVD) data in the south of China.The microphysical characteristics of WR and FR events are quite different.Compared with FR events,WR events have higher concentration of D<5.3 mm(especially D <1 ... 相似文献
69.
系统的采集端运行在搭载Android系统的平板上,使用Esri公司发布的ArcGIS for Android二次开发而成。数据处理端运行在PC端,使用Esri公司的ArcGIS for Engine构建。采集人员可以使用采集端快速录制视频或拍照进行数据采集,数据处理人员使用数据处理端导入采集端采集的数据进行处理获取最终的成果。结果表明:相对于传统的兴趣点采集技术,使用本系统不仅能提高采集效率,而且能有效地降低采集成本。 相似文献
70.
在双线偏振雷达试制过程中,其视频积分处理器(DVIP)不同于常规雷达的DVIP。即将常规雷达峰值采样的DVIP改为具有距离、方位双重积分的多点采样智能化的DVIP,以减小脉动,提高被测对象的稳定性。本文介绍了双线偏振DVIP的组成方式、特点及工作原理。 相似文献