全文获取类型
收费全文 | 2660篇 |
免费 | 511篇 |
国内免费 | 667篇 |
专业分类
测绘学 | 410篇 |
大气科学 | 557篇 |
地球物理 | 659篇 |
地质学 | 1224篇 |
海洋学 | 337篇 |
天文学 | 72篇 |
综合类 | 281篇 |
自然地理 | 298篇 |
出版年
2024年 | 31篇 |
2023年 | 73篇 |
2022年 | 179篇 |
2021年 | 219篇 |
2020年 | 160篇 |
2019年 | 165篇 |
2018年 | 183篇 |
2017年 | 178篇 |
2016年 | 177篇 |
2015年 | 158篇 |
2014年 | 138篇 |
2013年 | 170篇 |
2012年 | 143篇 |
2011年 | 162篇 |
2010年 | 135篇 |
2009年 | 129篇 |
2008年 | 132篇 |
2007年 | 116篇 |
2006年 | 102篇 |
2005年 | 92篇 |
2004年 | 69篇 |
2003年 | 57篇 |
2002年 | 84篇 |
2001年 | 72篇 |
2000年 | 68篇 |
1999年 | 116篇 |
1998年 | 93篇 |
1997年 | 93篇 |
1996年 | 68篇 |
1995年 | 43篇 |
1994年 | 38篇 |
1993年 | 44篇 |
1992年 | 33篇 |
1991年 | 32篇 |
1990年 | 16篇 |
1989年 | 21篇 |
1988年 | 6篇 |
1987年 | 11篇 |
1986年 | 9篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 5篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1977年 | 1篇 |
1958年 | 2篇 |
1957年 | 2篇 |
排序方式: 共有3838条查询结果,搜索用时 15 毫秒
151.
Li Xingxing Ma Tengzhou Xie Weiliang Zhang Keke Huang Jiaxin Ren Xiaodong 《GPS Solutions》2019,23(2):1-16
GPS Solutions - As parameter estimation and statistical testing are often intimately linked in the processing of observational data, the uncertainties involved in both estimation and testing need... 相似文献
152.
This paper presents the basic concepts and principles, data structure and high efficient spatial index for multi-resolution image database. The database is characterized by arrangement of multi-resource image data and seamless mosaic, distribution-based storage and management, integration with other spatial database software such as GeoStar and GeoGrid developed by Wuhan Technical University of Surveying and Mapping. 相似文献
153.
Xiaodong Zhang Ho Jin Kim Clinton Streeter David A. Claypool Ramesh Sivanpillai Santhosh Seelan 《国际地球制图》2013,28(7):537-551
Precision agriculture often relies on high-resolution imagery to delineate the variability within a field. Airborne Environmental Research Observational Camera (AEROCam) was designed to meet the needs of agriculture producers, ranchers, and researchers, who require high-resolution imagery in a near real-time environment for rapid decision support. AEROCam was developed and operated through a unique collaboration between several departments at the University of North Dakota, including the Upper Midwest Aerospace Consortium (UMAC), the School of Engineering and Mines, and flight operations at the John D. Odegard School of Aerospace Sciences. AEROCam consists of a Redlake MS4100 area-scan multi-spectral digital camera that features a 1920 × 1080 CCD array (7.4-μm detector) with 8-bit quantization. When operated at ~2 km above ground level, multispectral images with four bands in the visible and near infrared have a ground sample distance of 1 m with a horizontal extent of just over 1.6 km. Depending on the applications, flying at different altitudes can adjust the spatial resolution from 0.25 to 2 m. Rigorous spectral and radiometric calibrations allow AEROCam to be used in a variety of applications, qualitative and quantitative. Equipped with an inertial measurement unit (IMU) system, the images acquired can be geo-referenced automatically and delivered to end users near real time through our Digital Northern Great Plains system (DNGP). The images are also available to zone mapping application for precision farming (ZoneMAP), an online decision support tool for creating management zones from remote sensing imagery and data from other sources. Operational since 2004, AEROCam has flown over 250 sorties and delivered over 150,000 images to the users in the Northern Great Plains region, resulting in numerous applications in precision agriculture and resource management. 相似文献
154.
155.
156.
本文提出一种基于小面元相对配准的正射影像快速更新方法,该方法不涉及常规摄影测量的处理方法,而是直接利用新获取的卫星遥感影像和原始正射影像进行高精度小面元相对配准,然后将卫星遥感影像纠正到原始正射影像参考坐标系,进而实现正射影像的快速更新。 相似文献
157.
地面移动测量技术的发展与现状 总被引:1,自引:0,他引:1
地面移动测量技术是当前倍受关注的测量前沿技术。本文论述了地面移动测量技术的基本原理和特点,回顾了该技术的发展历史,总结了国内外研究现状,展望了今后的发展趋势与应用前景,并对研究、发展和应用这一技术提出了建议。 相似文献
158.
介绍了在建筑场地及厂房内部无控制网的情况下,利用精密工程测量的手段和方法,检验校正设备,提高安装精度,解决设备安装后存在的安装定位不精确问题的方法,以满足生产要求。 相似文献
159.
基于交互多模型的水下目标跟踪方法 总被引:1,自引:0,他引:1
According to the requirements of real-time performance and reliability in underwater maneuvering target tracking as well as clarifying motion features of the underwater target, an interacting multiple model algorithm based on fuzzy logic inference (FIMM) is proposed. Maneuvering patterns of the target are represented by model sets, including the constant velocity model (CA), the Singer mode~, and the nearly constant speed horizontal-turn model (HT) in FIMM technology. The simulation results show that compared to conventional IMM, the reliability and real-time performance of underwater target tracking can be improved by FIMM algorithm. 相似文献
160.
重点介绍了基于Flash平台制作多媒体综合电子地图集的开发集成方法以及具体功能的实现。 相似文献