全文获取类型
收费全文 | 635篇 |
免费 | 72篇 |
国内免费 | 61篇 |
专业分类
测绘学 | 182篇 |
大气科学 | 38篇 |
地球物理 | 39篇 |
地质学 | 314篇 |
海洋学 | 60篇 |
天文学 | 3篇 |
综合类 | 49篇 |
自然地理 | 83篇 |
出版年
2024年 | 2篇 |
2023年 | 14篇 |
2022年 | 12篇 |
2021年 | 15篇 |
2020年 | 25篇 |
2019年 | 34篇 |
2018年 | 17篇 |
2017年 | 33篇 |
2016年 | 38篇 |
2015年 | 21篇 |
2014年 | 34篇 |
2013年 | 58篇 |
2012年 | 43篇 |
2011年 | 51篇 |
2010年 | 38篇 |
2009年 | 40篇 |
2008年 | 44篇 |
2007年 | 38篇 |
2006年 | 44篇 |
2005年 | 29篇 |
2004年 | 20篇 |
2003年 | 16篇 |
2002年 | 23篇 |
2001年 | 14篇 |
2000年 | 10篇 |
1999年 | 15篇 |
1998年 | 7篇 |
1997年 | 8篇 |
1996年 | 4篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
1986年 | 3篇 |
1985年 | 1篇 |
1984年 | 2篇 |
排序方式: 共有768条查询结果,搜索用时 31 毫秒
101.
通过引入服务的主动发现、定制、加载与使用机制,支持新服务、新应用的按需创建,为用户发现、定制和运行能够满足用户需求的服务,从而改变当前用户只能被动地使用现有服务的应用模式,以应对信息化需求的不断发展和变化。主动型的地理信息服务在Web服务框架模型、基础协议的基础之上,增加识别用户需求和处理的能力,使用户能够根据特定需要选择合适的服务,使服务能够自动适应用户的需求。本文讨论了面向服务架构下的主动地理信息服务模型,该模型以Web服务技术为支撑,以扩展的UDDI等协议为规范,并对该模型进行测试,实验证明该模型可以有效地主动式的地理信息服务。 相似文献
102.
中国地震地球物理观测网络的核心业务软件“十五”地震前兆数据管理系统已运行十多年,随着观测数据量的增长,数据库的读取和统计查询的性能逐渐降低。此外,管理系统存在SQL注入和跨站脚本攻击等漏洞的安全问题,系统架构难以满足业务发展的需求。中国地震台网中心基于分布式组件的大数据架构,使用消息中间件和时序数据库等技术对管理系统进行重构,将原来存储于Oracle数据库中的地球物理观测数据、基础信息、产品数据等按照各自特点在时序数据库中建表,并将历史数据和增量数据都迁移到新的时序数据库,显著提升了系统读写和统计性能、数据的安全性和可用性(多副本技术)。分布式和容器化等技术的引入,增强了系统的高可用性,并可通过横向扩展进一步增加系统的处理能力。 相似文献
103.
目前的景观建筑设计中往往更注重建筑的景观性,而忽略了建筑的安全稳定性,导致景观建筑的整体抗震效果较差,在景观建筑设计中加入挡土墙设计可以有效提高其抗震性。为此,设计一种具有一定抗震性能的景观建筑挡土墙,利用建筑施工过程中保留的复合纤维材料、建筑垃圾以及纤维绳等作为土墙填充物,并加入具有一定抗拉能力的拉筋材料,以保持土墙内部的稳定性。考虑景观建筑通常注重外观视觉效果,使用"平改坡"设计,在墙体表面种植具有一定视觉冲击的植物,增加土墙自重,促进土墙整体结构的稳定性。分析挡土墙后面无限倾斜填土受力状态,选取菱形微小单元体作为研究对象,计算景观建筑的挡土墙土压力强度。实验证明,优化设计的景观建筑挡土墙结构可以有效增强景观建筑的整体抗震能力。 相似文献
104.
105.
106.
地理信息技术发展的新方向——网格GIS初探 总被引:4,自引:0,他引:4
网格GIS是网格及网格计算技术与GIS相结合而形成的新的GIS发展方向,具有空间资源共享、海量空间数据存储与处理、异地协同工作与异构系统支持等功能,在城市管理、房地产管理、资源勘测与调查等方面具有十分重要的作用。本文在分析网格GIS的概念及其特征的基础上,提出了网格GIS的四层结构体系,并简要介绍了网格GIS实现的关键技术。 相似文献
107.
Basin floor fans contain some of the largest deep-water hydrocarbon accumulations discovered, however they also demonstrate extremely complex stratigraphic architecture, understanding of which is crucial for maximum recovery. Here we develop a new method, based upon palynofacies analysis, for the distinction of the different depositional environments that are commonly associated with basin floor fans. Previous studies and our sedimentological analysis allow good confidence in the discrimination of the different depositional environments of the outcropping Marnoso-Arenacea Formation fan system. One hundred and thirty-five samples were collected from mudstones in conjunction with sedimentary logging of 871 m of outcrops. Six lithofacies associations are described and interpreted to represent lobe axis, lobe fringe, fan fringe, contained interlobe, basin plain, and starved high depositional sub-environments. Palynofacies of these elements demonstrate turbidites to be rich in terrestrial organic matter, with sixteen categories of matter recognised. The abundances and proportions of particles varies between sub-environments, with lobe axis deposits containing the largest, densest particles, with a transition to ever smaller and lighter particles moving toward the basin plain. Fuzzy C-means statistical analysis was used to explore this trend. Distribution of organic matter is not random, but is dominated by hydrodynamic sorting and sequential fall-out of particles as turbidity currents passed across the basin. This allows a palynofacies classification scheme to be constructed to assist the identification of depositional environments of submarine fans, which may be combined with subsurface data to assist reservoir characterisation. 相似文献
108.
The investigation of complex geological setting is still dominated by traditional geo-data collection and analytical techniques, e.g., stratigraphic logging, dip data measurements, structural ground mapping, seismic interpretation, balance section restoration, forward modelling, etc. Despite the advantages of improving our understanding in structural geometry and fault architecture, the geospatial modelling, applying computer-aided three-dimensional geometric design, visualization and interpretation, has rarely been applied to such complex geological setting. This study used the Lenghu fold-and-thrust belt (in Qaidam basin, NE Tibetan Plateau) to demonstrate that the application of geospatial and geomechanical modelling could improve our understanding and provide an effective technique for investigating the fault architecture and strain distribution. The three-dimensional configuration of the Lenghu fold-and-thrust belt was initially derived from traditional analysis techniques, such as regional stratigraphic logging, cross section construction, meso-scale ground mapping and landsat image interpretation. The high-resolution field data and landsat image were integrated to construct the geospatial model, which was subsequently used to quantitatively investigate the fault throw changes along the Lenghu thrust fault zone and to understand its control on the lateral structural variation. The geospatial model was then restored in three dimensions to reveal the kinematic evolution of the Lenghu fold-and-thrust belt. Geomechanical modelling, using a Mass-Spring algorithm, provided an effective three-dimensional tool for structural strain analysis, which was used to predict the strain distribution throughout the overall structure, e.g., normal faults with throws ranging from meters to tens of meters in the hanging-wall. The strain distribution predicted by geomechanical modelling was then validated by the natural normal faults in the hanging-wall. The high accordance between the strain prediction and statistics of natural normal faults demonstrates good applicability of geospatial and geomechanical modelling in the complex geological setting of the Lenghu fold-and-thrust belt. The geospatial models and geomechanical models, therefore, can provide a robust technique for analyzing and interpreting multi-source data within a three-dimensional environment. We anticipate that the application of three-dimensional geospatial modelling and geomechanical modelling, integrating both multi-source geologic data and three-dimensional analytical techniques, can provide an effective workflow for investigating the fault architecture and strain distribution at different scales (e.g., ranging from regional-to meso-scale). 相似文献
109.
地磁台网高压直流输电判别处理系统设计 总被引:3,自引:2,他引:1
介绍地磁高压直流输电干扰自动判断处理系统的主要功能、架构设计和运行流程,并对其核心功能的实现过程进行描述。本系统为全国地磁观测人员处理高压直流输电干扰提供具体时间、幅度参考标准,有利于地磁预处理数据质量的提高。 相似文献
110.