全文获取类型
收费全文 | 595篇 |
免费 | 44篇 |
国内免费 | 30篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 118篇 |
地球物理 | 172篇 |
地质学 | 215篇 |
海洋学 | 69篇 |
天文学 | 1篇 |
综合类 | 15篇 |
自然地理 | 74篇 |
出版年
2024年 | 1篇 |
2023年 | 6篇 |
2022年 | 14篇 |
2021年 | 13篇 |
2020年 | 17篇 |
2019年 | 19篇 |
2018年 | 15篇 |
2017年 | 22篇 |
2016年 | 30篇 |
2015年 | 25篇 |
2014年 | 32篇 |
2013年 | 37篇 |
2012年 | 35篇 |
2011年 | 33篇 |
2010年 | 37篇 |
2009年 | 46篇 |
2008年 | 62篇 |
2007年 | 54篇 |
2006年 | 31篇 |
2005年 | 26篇 |
2004年 | 17篇 |
2003年 | 11篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 7篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有669条查询结果,搜索用时 31 毫秒
221.
222.
我国GIS产业面临严峻的挑战与发展的机遇 ,在GIS产业的发展中 ,应学会灵活运用资本市场与GIS产业的关系 ,利用资本市场完善GIS企业制度、筹措资金、实现GIS企业的跳跃式发展 相似文献
223.
《地学前缘(英文版)》2018,9(6):1679-1687
New sensing and wireless technologies generate massive data. This paper proposes an efficient Bayesian network to evaluate the slope safety using large-quantity field monitoring information with underlying physical mechanisms. A Bayesian network for a slope involving correlated material properties and dozens of observational points is constructed. 相似文献
224.
《Geoforum》2015
This article examines the science–policy interface in volcanic risk assessment. It analyses empirical data from research on Montserrat, where new volcanic risk assessment methodologies were pioneered. We discuss the ways in which these methods contributed towards the ordering of scientific advice in its geographical context, and we provide examples of the complex and overlapping topologies that are assembled in a volcanic eruption. In this case, the science–policy interface can be conceptualised as diffusive: both science and policy contain multiple overlapping networks of actors, objects and ideas that interact with one another through flows of responsibilities, attribution, identity and interpretation. Volcanic risk management involves negotiation of conceptual, relational and physical boundaries, and as a result requires the use of qualitative and quantitative methods across human and physical geography. 相似文献
225.
A successful piece of applied research will not only influence the related problem perception within the scientific community, but also lead to much better understanding of a complex challenge, including the delivery of solutions. Ideally it may contribute significantly to reducing possible risk situations for people and/or the natural environment. In short, a successful study will have a broader impact beyond the sphere of science. Planning, timing, funding, networking, communication, and interdisciplinarity are identified as key aspects for a successful project and are being examined in their scope and boundary conditions, while not neglecting the particular role of local and regional people and authorities.Defining what makes a successful environmental geochemical study is clearly based upon experience and evidence found, and not upon any particular theoretical concept. Here, experience is drawn from the outcome of many projects and specifically first-hand from the complex ARSENEX project in Minas Gerais, Brazil. Against the backdrop of both perceived and real arsenic contamination of environmental compartments, including local people, all subsequent project steps and proposals were set up using a three-prong approach that sought to a) understand the processes, b) educate and inform the public and all other stakeholders and c) remediate the situation. 相似文献
226.
We investigated the effects of elevated pCO2 in seawater both on the acute mortality and the reproductive properties of the benthic copepod Tigriopus japonicus and gastropod Babylonia japonica with the purpose of accumulating basic data for assessing potential environmental impacts of sub-sea geological storage of anthropogenic CO2 in Japan. Acute tests showed that nauplii of T. japonicus have a high tolerance to elevated pCO2 environments. Full life cycle tests on T. japonicus indicated NOEC = 5800 μatm and LOEC = 37,000 μatm. Adult B. japonica showed remarkable resistance to elevated pCO2 in the acute tests. Embryonic development of B. japonica showed a NOEC = 1500 μatm and LOEC = 5400 μatm. T. japonicus showed high resistance to elevated pCO2 throughout the life cycle and B. japonica are rather sensitive during the veliger stage when they started to form their shells. 相似文献
227.
《Geoforum》2014
Amid a rapid expansion of global investments in biofuels there has been an equally rapid proliferation of concerns about the inadequacies of current governance schemes to mitigate the environmental impacts of growing agroenergy production. Managing the land use practices of small producers in a way that ensures their activities are financially and environmentally sustainable is a particularly pressing issue that has been overlooked in research on biofuel governance. I illuminate these challenges through an ethnographic study on the multiple breakdowns of environmental governance in the Southern Goiás region of Brazil, a major expansion region for sugarcane ethanol production. I focus on one of the most pressing compliance issues among small and medium size sugarcane farmers; their persistent use of federally mandated conservation areas for cattle production. I find that while these transgressions are often perceived by administrators and officials as being the result of a lack of “environmental awareness” among rural farmers, they are better understood as a safety net to protect landowners against perceived risks of sugarcane production. These violations are further enabled by continuing ambiguity in the enforcement structure for conservation legislation in the region. Recalibrating regulatory systems to better address these issues of accountability and risk is a critical step toward improving environmental governance of global biofuel commodity chains. 相似文献
228.
由于风暴潮灾害常年对我国造成严重影响,因此国内许多沿海省(自治区、直辖市)均开展了风暴潮灾害风险评估与区划工作。随着该工作的陆续完成,考虑全局风暴潮灾害风险管理的需要,即将面临相邻地区成果衔接或集成的问题。为此,文章开展了相邻地区风暴潮灾害风险评估与区划成果集成方法的初步研究,提出潮位、增水、淹没水深、危险性、脆弱性、风险等级和风险区划等模型计算或评估结果的分类集成方法,并以上海市沿海5区的3个区域风暴潮模型的计算和评估结果为基础进行了方法应用,成功获得了上海全市的集成成果。文章提出的成果集成方法旨在为全国其他沿海省(自治区、直辖市)、县的成果集成提供方法借鉴。 相似文献
229.
230.
IPCC《气候变化中的海洋和冰冻圈特别报告》评估了全球和区域海洋的气候变化及其对生态系统和人类社会的影响、风险及应对措施。结果表明,近几十年来,海洋的物理和化学性质发生了明显变化,如升温、酸化、脱氧和营养盐减少等气候致灾因子(事件)的危害(险)性不断加剧(高信度)。这种变化正在影响从上层到底层的海洋生态系统和人类社会的可持续发展,如海洋初级生产力的下降、物种地理分布的变迁、渔业资源潜在渔获量的下降以及食品供应的减少(高信度)。在气候变化与非气候人为干扰因素的综合影响下,随着温室气体排放的增加(从RCP2.6到RCP8.5情景),到21世纪末,几乎所有类型的海洋和海岸带生态系统将处于高或很高的风险水平(高信度);其中,暖水珊瑚礁生态系统尤其严重,如果全球升温1.5℃和2℃,将分别消失70%~90%和99%以上(很高信度)。然而,当前多种减缓气候变化的海洋应对措施的作用较小,有的可能带来生态危险,而许多降低气候风险的海洋适应措施的作用也很有限,特别是在RCP8.5情景下的作用更小;未来海洋生态系统的风险水平在RCP2.6情景下均低于RCP8.5情景(很高信度)。因此,这凸显了减缓气候变化尤其是减缓和适应气候变化综合治理的重要性。 相似文献