全文获取类型
收费全文 | 1700篇 |
免费 | 345篇 |
国内免费 | 563篇 |
专业分类
测绘学 | 50篇 |
大气科学 | 159篇 |
地球物理 | 1117篇 |
地质学 | 952篇 |
海洋学 | 184篇 |
天文学 | 3篇 |
综合类 | 51篇 |
自然地理 | 92篇 |
出版年
2024年 | 7篇 |
2023年 | 49篇 |
2022年 | 63篇 |
2021年 | 57篇 |
2020年 | 86篇 |
2019年 | 110篇 |
2018年 | 108篇 |
2017年 | 65篇 |
2016年 | 108篇 |
2015年 | 92篇 |
2014年 | 126篇 |
2013年 | 128篇 |
2012年 | 100篇 |
2011年 | 109篇 |
2010年 | 108篇 |
2009年 | 137篇 |
2008年 | 120篇 |
2007年 | 134篇 |
2006年 | 121篇 |
2005年 | 110篇 |
2004年 | 88篇 |
2003年 | 113篇 |
2002年 | 70篇 |
2001年 | 62篇 |
2000年 | 56篇 |
1999年 | 45篇 |
1998年 | 44篇 |
1997年 | 41篇 |
1996年 | 42篇 |
1995年 | 29篇 |
1994年 | 24篇 |
1993年 | 14篇 |
1992年 | 12篇 |
1991年 | 12篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 2篇 |
1986年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
1978年 | 1篇 |
排序方式: 共有2608条查询结果,搜索用时 11 毫秒
71.
楼梯间作为地震中人员疏散和救援通道,其抗震设计应引起足够的重视.我国2010年实行的《建筑抗震设计规范》(GB50011-2010)中加强了结构中楼梯间的设计要求,结合该规范的实施,本文总结了芦山地震中各类结构中楼梯间的震害现象.通过对梯板、楼梯间墙体、与楼梯间相连的主体结构等位置的震害分析,指出了规范中关于楼梯间新增条文的必要性;提出了一些抗震设计建议,为规范修订和工程设计提供参考. 相似文献
72.
以茶叶萌芽至展叶期寒冻害为突破口,利用1987—2016年福建省泉州市安溪县17个自动气象站2—4月的逐日气象数据及安溪各茶树种植区产量数据,确定茶叶寒冻害的天气指数保险气象指标,分析日极端最低气温与茶叶减产率的关系,建立了茶叶寒冻害指数模型。计算安溪不同区域茶叶种植区不同等级寒冻害的发生概率,应用纯保费率方法厘定了保险费率,并根据福建省政策性农业保险的实际情况,制定茶叶不同区域种植区寒冻害指数保险触发条件、赔付标准,设计了安溪县茶叶寒冻害天气指数保险合同。设计的茶叶寒冻害天气指数保险产品以客观气象数据作为定损依据,可以为茶农提供一种有效的风险转嫁方式,也为保险公司增加新险种提供了技术支撑。 相似文献
73.
The Warsaw International Mechanism for Loss and Damage (L&D) associated with Climate Change Impacts (WIM) was established in 2013 to advance i) knowledge generation; ii) coordination and iii) support to address losses and damages under the UNFCCC. So far, the work undertaken by the WIM Executive Committee (ExCom) has focused on enhancing understanding and awareness of the issue and promoting collaboration with relevant stakeholders. Delivering on the WIM’s third function on action and support has lagged behind, and ‘the political’ nature of L&D has often been blamed for this. Key terrains of contention among Parties have included the positioning of L&D governance vis-à-vis the adaptation space and struggles around state liability and compensation. As a way to facilitate discussion on implementation options, recent research has suggested de-politicising aspects of the L&D debate; yet we have very little insight into how the politics are understood within the realm of international L&D governance. This paper brings an analysis of ‘the political’ into the picture by identifying the complex and underlying issues that fuel contention within UNFCCC L&D negotiations. It gives centre stage to the way different framings of norms and material interests affect the debate, and challenges the tendency in current L&D literature to overlook the socio-historical and political underpinnings of this area of policy-making. We employ a qualitative multi-methods research design which draws on content analysis of 138 official Parties’ submissions and statements, 14 elite interviews with key current and former L&D negotiators and is built on a foundation of 3 years of participant observation at COPs and WIM meetings. We approach this data with a political ethnographic sensibility that seeks to explore how meanings are constructed within and across different sources of data. Our empirical results show that, rather than being a monolithic dispute, L&D catalyses different yet intertwined unresolved discussions. We identify five areas of contention, including continued disputes around compensation; conflicts on the legitimacy of L&D as a third pillar of climate action; tensions between the technical and political dimension of the debate; debates over accountability for losses and damages incurred; and the connection of L&D with other unresolved issues under the Convention. 相似文献
74.
75.
近50年河南降水变化对水资源的影响 总被引:4,自引:0,他引:4
利用河南32个代表站1951~2002年降水量资料,分析了20世纪50年代以来全省年降水资源和水资源的变化趋势以及对旱涝灾害的影响。结果表明,自20世纪80年代中期以来,河南已进入一个降水量偏少时期,干旱化程度加重,水资源短缺已成为影响工农业生产和国民经济发展的主要因素。 相似文献
76.
2005年11月26日九江--瑞昌5.7级地震浅析 总被引:8,自引:0,他引:8
2005年11月26日,在江西省九江县与瑞昌市交界处发生5.7级地震,震源深度10km。宏观震中在九江县港口乡。震中烈度Ⅶ度,极震区为北东向的椭圆,烈度分布受瑞昌盆地内地形地貌条件的控制;5.7级地震的最大余震为ML5.3级,序列类型为主震—余震型,余震较丰富,余震区长轴为北西向。此次地震经历了较长期的应力应变积累过程,发生在江西分宜—黄海北部北东向ML≥4.0级地震活动带和湖北西部—江西南昌ML≥3.0级地震活动带的交汇部位,与大区域地震活动性中长期异常相关。 相似文献
77.
黑龙江省玉米低温冷害风险评估及预估 总被引:1,自引:0,他引:1
利用气候资料、地理信息数据及社会经济数据,根据自然灾害风险理论和低温冷害形成机制,采用GIS技术,分析了黑龙江省玉米低温冷害的危险性和易损性,实现了玉米低温冷害的风险评估与区划,并利用CMIP5中的MRI-CGCM3模式模拟结果对黑龙江省2015-2044年玉米低温冷害风险进行预估。结果表明:1961年以来共有24年是低温冷害年,其中12年是严重低温冷害年。松嫩平原大部、三江平原大部及黑河南部是玉米一般低温冷害的多发区,同时该区暴露性较高,如有重度灾害发生,则对全省粮食产量产生严重影响。未来30年,黑龙江省低温冷害发生的概率有所减少,松嫩平原东部和南部是一般低温冷害的高风险区,三江平原西部是严重低温冷害的高风险区。 相似文献
78.
Jonathan Gewirtzman Sujay Natson Julie-Anne Richards Victoria Hoffmeister Alexis Durand Romain Weikmans 《Climate Policy》2018,18(8):1076-1086
After decades of pressure from vulnerable developing countries, the Warsaw International Mechanism on Loss and Damage (the WIM) was established at the nineteenth Conference of the Parties (COP 19) in 2013 to address costly damages from climate change. However, little progress has been made towards establishing a mechanism to fund loss and damage. The WIM's Executive Committee issued its first two-year workplan the following year at COP 20 which offered, among other things, a range of approaches to financing loss and damage programmes, which we review here. We provide brief overviews of each mechanism proposed by the WIM ExCom, describe their current applications, their statuses under the United Nations Framework Convention on Climate Change (UNFCCC), some of their advantages and disadvantages, and their current or potential application to loss and damage. We find that several of these mechanisms may be useful in supporting loss and damage programmes, but identify some key gaps. First, most of the mechanisms identified by the WIM ExCom are insurance schemes subsidized with voluntary contributions, which may not be adequate or reliable over time. Second, none were devised to apply to slow-onset events, or to non-economic losses and damages. That is, if harms are inflicted on parts of a society or its ecosystems that have no price, or if they occur gradually, they would probably not be covered by these mechanisms. Finally, the lack of a dedicated and adequate flow of finance to address the real loss and damage being experienced by vulnerable nations will require the use of innovative financial tools beyond those mentioned in the WIM ExCom workplan.
Key policy insights
Despite a full article of the 2015 Paris Agreement devoted to loss and damage, there is little international agreement on the scope of loss and damage programmes, and especially how they would be funded and by whom.
Most of the loss and damage funding mechanisms identified by the WIM ExCom are insurance schemes subsidized with voluntary contributions, which may burden the most vulnerable countries and may not be reliable over time.
None of the mechanisms were devised to apply to slow-onset events, or to non-economic losses and damages.
79.
80.