全文获取类型
收费全文 | 944篇 |
免费 | 151篇 |
国内免费 | 79篇 |
专业分类
测绘学 | 12篇 |
大气科学 | 37篇 |
地球物理 | 102篇 |
地质学 | 281篇 |
海洋学 | 547篇 |
天文学 | 2篇 |
综合类 | 36篇 |
自然地理 | 157篇 |
出版年
2024年 | 4篇 |
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 27篇 |
2020年 | 26篇 |
2019年 | 37篇 |
2018年 | 29篇 |
2017年 | 25篇 |
2016年 | 27篇 |
2015年 | 34篇 |
2014年 | 33篇 |
2013年 | 77篇 |
2012年 | 41篇 |
2011年 | 42篇 |
2010年 | 40篇 |
2009年 | 49篇 |
2008年 | 45篇 |
2007年 | 47篇 |
2006年 | 53篇 |
2005年 | 38篇 |
2004年 | 54篇 |
2003年 | 41篇 |
2002年 | 28篇 |
2001年 | 30篇 |
2000年 | 32篇 |
1999年 | 27篇 |
1998年 | 33篇 |
1997年 | 21篇 |
1996年 | 9篇 |
1995年 | 23篇 |
1994年 | 17篇 |
1993年 | 10篇 |
1992年 | 10篇 |
1991年 | 11篇 |
1990年 | 8篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 7篇 |
1985年 | 11篇 |
1984年 | 17篇 |
1983年 | 24篇 |
1982年 | 25篇 |
1981年 | 26篇 |
1980年 | 1篇 |
1976年 | 1篇 |
1882年 | 1篇 |
排序方式: 共有1174条查询结果,搜索用时 0 毫秒
1.
Sarah L. Holloway 《Geoforum》2007,38(1):7-20
In the past decade geographers have critiqued the exclusivity of idyllic representations of rurality and sought to explore the diverse experiences of Other social groups in the countryside. This paper builds upon that small but significant strand of research which has highlighted the whiteness of representations of rurality and the consequences of this for racialised minorities. These debates have been crucially important in forwarding our understanding of racially-exclusive constructions of idyllic country living; however, it is important that academics neither assume that such ideas are forever fixed, nor that they affect all minority ethnic groups in the same ways. This paper takes both the potential power and frailty of these ideas seriously, as it examines how the concepts of race, racism and rurality are deployed by different commentators as they debate the place of one specific minority ethnic group in the English countryside. The route taken into this is a consideration of print-media reporting of events in Firle, Sussex, where, in 2003, some white rural residents symbolically purged their village of Gypsy-Travellers by burning a mock caravan complete with effigies at their annual bonfire celebrations. In conclusion, the paper challenges the relative lack of attention to these issues within the white-dominated discipline of geography, and argues that it is imperative to trace the dynamic ways in which the whiteness of idyllic understandings of the rural are reinforced and challenged through contemporary social practice. 相似文献
2.
滨岸地带自然环境多变,地质环境极为脆弱,但在社会经济发展中起着极为重要的作用。着重分析我国东部滨岸侵沉变异特征,研究滨岸侵沉变异地域分异规律与成因规律。 相似文献
3.
This paper provides a comparative analysis of two separate national surveys of the uptake and use of Geographical Information Systems (GIS) by Health Authorities (HAs) in England and Wales. The surveys were undertaken at two different time points (1991 and 2001), and the intervening period has been characterized by major (and continuing) health sector restructuring. The substantial number of HA mergers between 1991 and 2001 provide a methodological challenge in attempting to make comparisons. A pragmatic approach is adopted and the presentation of results has to be restricted solely to English and Welsh HA data. Our findings show that there has been a considerable increase in the use of GIS since the early 1990s, and there is some evidence of more sophisticated uses for a wider range of policy-related and application tasks. However, we conclude that there is still considerable scope for the wider uptake and use of GIS within the NHS. In addition, our findings provide a baseline with which to monitor the impacts of future organizational restructuring on the uses of GIS within the NHS. We suggest that this is important given the replacement of 95 English HAs with 28 new Strategic HAs (StHAs) from April 2002, and the repercussions of the anticipated shift in GIS responsibility to Primary Care Trusts. 相似文献
4.
根据沙河、正定、商丘、东营四测站三天同步测量所获取的地磁日变数据,提出了三种局部地区地磁日变的拟合方法;井通过对四测站三天地磁日变曲线的分析发现了时差对日变曲线的非均衡影响以及东营日变具比较明显的海岸效应之影响。 相似文献
5.
海岸侵蚀灾害管理中的几项基础工作 总被引:3,自引:2,他引:3
讨论了作为海岸带管理工作中一项重要管理内容──海岸侵蚀灾害管理中的几项基础性工作,主要讨论了灾害评估的意义;海岸侵蚀灾害管理基础图件和专业图件的名称及主要内容;建立海岸侵蚀灾害信息系统的意义和主要内容;关于海岸侵蚀灾害管理法的意义和急迫性;提出了建立禁建区和禁采区的意义和紧迫性,并指出在海岸带开发建设中要统一管理,全面规划,注意到海岸带生态环境的特殊性。总之在海岸侵蚀灾害管理中,首先要做好基础工作,在此基础上做好法制建设和依法管理。 相似文献
6.
In the Western Lake Baikal, recent Baikal Rift's tectonics control the topography, seismicity, climate, geomorphology, and economy. Scarps, facets, structural terraces, horsts and grabens, and trapezoid valleys can be clearly observed. They have been generated by the recent tectonic movements along the faults and represent a serious geologic hazard. The specific geological conditions predetermine a unique variety of landscapes. Thus, the main type of the economy is tourism. However, unorganized tourism leads to the degradation of the unique landscapes. It increases risk and requires disaster management. Three criteria has been used for risk assessment: (1) degree of geologic hazard; (2) degree of landscape degradation; and (3) degree of the economy's vitality. The high ecological significance and low stability to antropogeneous pressure are typical for landscapes of the Western Lake Baikal. Thus, some special activities of disaster management should be implemented based on our investigation. 相似文献
7.
海岸侵蚀是沿海各国面临的共同问题,海滩养护是当前砂质海岸保护的最佳手段,在全球范围内得到广泛应用。本文回顾了海滩养护技术的发展历程,总结了世界范围的海滩养护实践,分析各国海滩养护理念上存在的差异。以研究文献为基础,总结归纳了平面和横向剖面的补砂方式、辅助工程技术和海滩模型预测等方面的海滩养护技术研究进展,并在此基础上提出了海滩养护的未来发展趋势:①针对复杂海岸的海滩养护应用拓展;②基于沉积物管理的海滩养护修复;③从地貌系统到生态系统全面考虑的海滩养护技术;④全球砂源赤字条件下的海滩保护和修复思路。 相似文献
8.
9.
10.