全文获取类型
收费全文 | 148篇 |
免费 | 26篇 |
国内免费 | 5篇 |
专业分类
测绘学 | 13篇 |
大气科学 | 7篇 |
地球物理 | 21篇 |
地质学 | 28篇 |
海洋学 | 61篇 |
天文学 | 1篇 |
综合类 | 15篇 |
自然地理 | 33篇 |
出版年
2024年 | 1篇 |
2022年 | 5篇 |
2021年 | 3篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 7篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 8篇 |
2012年 | 6篇 |
2011年 | 5篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 13篇 |
2007年 | 15篇 |
2006年 | 6篇 |
2005年 | 4篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 4篇 |
1985年 | 10篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 3篇 |
1954年 | 1篇 |
排序方式: 共有179条查询结果,搜索用时 0 毫秒
81.
82.
83.
Ted L. McDorman 《Marine Policy》1985,9(4):292-309
This article considers Thailand's problems with the 1982 LOS Convention, especially the exclusive economic zones. Despite the disadvantages, it recommends that Thailand should ratify the Convention. 相似文献
84.
85.
Management of straddling fish stocks has been noted for its political complexity. Negotiations frequently falter as each party seeks to focus upon their own individual and shorter-term goals than the collective interest of the sector. Entrenched positions are often only deepened as new entrants participate to establish their own claims to any emergent share of resource. Unsurprisingly, deadlocks are common and typically compromises are reached only after the real period of biological then economic crisis has passed. Examples to illustrate this tendency can be found in most of the world's oceans and is writ large within the current impasse over blue whiting (Micromesistius poutassou) in the North Atlantic. The development of this fishery is discussed and it is shown that despite the scope to add value to the resource base through a pattern of exploitation focussed more upon human consumption than fish meal and oil, there seems little incentive to extricate participants from the cycle of demise that has engulfed negotiations so far. 相似文献
86.
北极在气候、资源、航道、科考等诸多领域对我国有着重要的现实和潜在价值,科考活动在资源争夺上的工具价值更是独一无二,同时,科考作为低敏感领域的活动也最容易开展合作。《联合国海洋法公约》和《斯匹次卑尔根群岛条约》是目前北极科考活动主要的法律规范。作为发展中大国,中国既有对北极科考的法律依据又有雄厚的科研实力。北极科考活动的拓展关涉中国在北极航道、渔业、投资等领域重要的国家利益,也有利于我国未来在北极事务中占有一席之地。因此,我国应进一步加大北极科考活动力度,参与北极科考活动法律规范的制定,进而提升我国在北极事务中的参与权和发言权。 相似文献
87.
Spaces of enclosure 总被引:1,自引:0,他引:1
Building on recent critical scholarship by authors including Retort [Retort, 2005. Afflicted Powers: Capital and Spectacle in a New Age of War. Verso, London] and Ferguson [Ferguson, J., 2006. Global Shadows: Africa in the Neoliberal World Order. Duke University Press, Durham, NC], this critical review will explore the inter-articulation of neoliberal norms and a resurgent and violent form of geo-politics through the rubric of ‘enclosure’. We believe that ‘enclosure’ serves as an appropriately flexible concept that speaks not only to the vagaries of primitive accumulation but also to the recent recrudescence of an aggrandized mode of statist violence. We argue that enclosure operates contingently, provisionally, and violently across a range of scales, sites, and networks and sketch four preliminary axes of investigation: subjectification, legal violence, the colonial present, and the politics of representation. The review goes on to suggest a set of markers through which to widen the conceptual and political purchase of enclosure through the geoeconomic, geopolitical and biopolitical, and highlights distinct spatial formations, modes of subjectification, and technologies of power through which enclosure variously operates. 相似文献
88.
Data‐driven modelling of shortwave radiation transfer to snow through boreal birch and conifer canopies 下载免费PDF全文
Hydrological and land surface models require simple but accurate methods to predict the solar radiation transmitted through vegetation to snow, backed up by direct comparisons to data. Twenty shortwave pyranometers were deployed in forest plots of varying canopy structures and densities in sparse birch forest near Abisko, Sweden, in spring 2011 and mixed conifer forest near Sodankylä, Finland, in spring 2012. Above‐canopy global and diffuse shortwave irradiances were also measured. These data were used to test a model that uses hemispherical photographs to explicitly estimate both diffuse radiation and direct beam transmission, as well as two models that apply bulk canopy parameters and versions of Beers Law. All three models predict canopy shortwave transmission similarly well for leafless birch forest, but for conifers, the bulk methods perform poorly. In addition, an existing model of multiple reflections between canopy and snow was found to be suitable for birch, but not conifers. A new bulk approach based on empirical relationships with hemisphere‐averaged sky view fraction showed improved performance for both sites; this suggests benefits of avoiding the use of plant area index calculated from optical methods, which can introduce errors. Furthermore, tests using common empirical diffuse radiation models were shown to underestimate shortwave transmission by up to 7% relative to using the data, suggesting that new diffuse models are required for high latitudes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
89.
Sand PH 《Marine pollution bulletin》2007,54(4):374-376
The first wave of unilaterally declared environmental protection zones (starting with Canada's Arctic Waters Pollution Prevention Act of 1970) may have been halted by the 1982 UN Convention on the Law of the Sea. Yet, a second wave now seems to be gaining momentum: the French 'ecological protection zone in the Mediterranean' of April 2003 (promptly emulated by Croatia, Slovenia, and Italy), the British 'environment (protection and preservation) zone' around the Chagos Archipelago of September 2003, and the US 'marine national monument' around the Northwestern Hawaiian Islands of June 2006, all claiming new environmental regulatory powers in sea areas way beyond territorial waters. This viewpoint article questions the unilateral legitimation of those claims, and postulates a trusteeship ethos and fiduciary accountability for ocean governance in these areas. 相似文献
90.
地表水与地下水相互转化关系一直是水文地质研究的热点问题。以往研究更多关注河流的河岸带,但对于相对静止水体——湖泊的湖岸带研究相对偏少。选择白洋淀湖岸带作为研究对象,在周边湖岸带系统部署水位、水温监测系统,采用温度示踪法,开展白洋淀湖岸带区域的地表水与地下水垂向交换量化研究。同时,结合达西定律,间接反演获取垂向渗透系数,系统总结出一套联合利用温度示踪法和达西定律定量研究湿地垂向水交换的方法。结果表明,白洋淀湖岸带以地表水渗漏补给地下水为主,其垂向交换流速可达0.2~1.1 cm/d,沉积岩性主要为粉质黏土、粉土及粉细砂,垂向渗透系数为0.038~0.912 m/d。研究结果可为制定白洋淀湿地补水方案和生态环境保护措施提供基础数据支撑。 相似文献