全文获取类型
收费全文 | 612篇 |
免费 | 43篇 |
国内免费 | 30篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 130篇 |
地球物理 | 168篇 |
地质学 | 217篇 |
海洋学 | 76篇 |
综合类 | 13篇 |
自然地理 | 76篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 13篇 |
2021年 | 14篇 |
2020年 | 20篇 |
2019年 | 20篇 |
2018年 | 16篇 |
2017年 | 33篇 |
2016年 | 30篇 |
2015年 | 27篇 |
2014年 | 36篇 |
2013年 | 40篇 |
2012年 | 38篇 |
2011年 | 34篇 |
2010年 | 31篇 |
2009年 | 48篇 |
2008年 | 61篇 |
2007年 | 53篇 |
2006年 | 29篇 |
2005年 | 27篇 |
2004年 | 17篇 |
2003年 | 12篇 |
2002年 | 15篇 |
2001年 | 9篇 |
2000年 | 10篇 |
1999年 | 10篇 |
1998年 | 8篇 |
1997年 | 4篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 6篇 |
1992年 | 2篇 |
1991年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有685条查询结果,搜索用时 15 毫秒
31.
This paper considers how farmers perceive and respond to climate change policy risks, and suggests that understanding these risk responses is as important as understanding responses to biophysical climate change impacts. Based on a survey of 162 farmers in California, we test three hypotheses regarding climate policy risk: (1) that perceived climate change risks will have a direct impact on farmer's responses to climate policy risks, (2) that previous climate change experiences will influence farmer's climate change perceptions and climate policy risk responses, and (3) that past experiences with environmental policies will more strongly affect a farmer's climate change beliefs, risks, and climate policy risk responses. Using a structural equation model we find support for all three hypotheses and furthermore show that farmers’ negative past policy experiences do not make them less likely to respond to climate policy risks through participation in a government incentive program. We discuss how future research and climate policies can be structured to garner greater agricultural participation. This work highlights that understanding climate policy risk responses and other social, economic and policy perspectives is a vital component of understanding climate change beliefs, risks and behaviors and should be more thoroughly considered in future work. 相似文献
32.
Commonly used earthquake “whole process” frequency - magnitude and strain energy - magnitude laws are merged to obtain an
analytic expression for an upper bound magnitude to regional earthquake occurrenceM
3, which is expressed primarily in terms of the annual maximum magnitudeM
1 and the magnitude equivalent of the annual average total strain energy releaseM
2. Values ofM
3 are also estimated graphically from cumulative strain energy release diagrams. Both methods are illustrated by application
to the high seismicity of the circum-Pacific belt, using Duda’s (1965) data and regionalisation. Values ofM
3 obtained analytically, with their uncertainties, are in agreement with those obtained graphically. Empirical relations are
then obtained betweenM
1,M
2, andM
3, which could be of general assistance in regional seismic risk considerations if they are found to be of a universal nature.
For instance.M
3 andM
2 differ by one magnitude unit in subregions of the circum-Pacific. 相似文献
33.
Nature-triggered hazards and disasters have traditionally been treated only from the lens of geophysical and biophysical processes,
implying that the root cause of large-scale death and destruction lies in the natural domain rather than in a coupled human–environment
system. Conceptually, the physical domain has been seen as discrete and separate from human entities, and solutions were sought
in the technological intervention and control of the physical environment—solutions that often ended up being less effective
than hoped for and sometimes even counter productive. At all levels, institutions have directed and redirected most of their
financial and logistical resources into the search for scientific and engineering solutions without allocating due attention
and resources towards the assessment of effects and effectiveness of the applications of such technological outcomes. However,
over the last two decades, forceful criticisms of the ‘dominant’ technocratic approach to hazards analysis have appeared in
the literature and consequently there has not only been a shift in thinking of causation of disaster loss in terms of human
vulnerability, but also newer questions have arisen regarding distinguishing between the ‘physical exposure’ of people to
threats and societal vulnerability, and linking them with propensity to hazards loss.
Though the vulnerability/resilience paradigm has largely replaced the hazards paradigm within the social sciences and much
of the professional emergency and disaster management communities, this shift of thinking has not progressed to much of the
physical science community, decision-makers and the public, who have not yet accepted the idea that understanding and using
human and societal dimensions is equally or more important than trying to deal and control nature through the use of technology.
This special issue is intended to further the idea that the aspects of community and peoples’ power to mitigate, to improve
coping mechanisms, to respond effectively, and recover with vigor against the environmental extremes are of paramount conceptual
and policy importance. 相似文献
34.
In this paper, a simple scenario and probabilistic approach is used to assess the potential groundwater risk due to proposed
overdraft remedial actions in cone of depression, Jining City, China. Focusing on the concentrations of Chloride ions (Cl−) and total hardness (TH), the impact of artificial recharge and reduced pumping on groundwater quality and quantity is analysed
by using the three-dimensional finite difference groundwater flow and transport model, Visual MODFLOW, to simulate groundwater
flow and transport within the study area based on scenarios, and utilizes SURFER software to map risk levels. Although 5,
10 or 15% reduced pumping with artificial recharge leads to more decrease in Cl− and TH concentrations than the 25%, less volume increase is achieved for the remediation of land subsidence and other environmental
problems in the cone of depression. The Cl− concentrations in recovered groundwater are within the desired concentration of 200 mg/l; however, TH in some cases are above
the maximum permissible limit of 500 mg/l, with an exceedence probability of about 0.67 for recharge and recharge with reduced
pumping at 25%. The presence of fractures and hydrogeological complexity greatly determines impacts of remediation, and the
22% reduced pumping with artificial recharge offers an optimum strategy for overdraft remediation in the Jining cone of depression. 相似文献
35.
国外灾害风险管理对我国城市洪水保险的启示 总被引:3,自引:0,他引:3
全球变化和城市化的共同作用将导致城市洪涝灾害加剧,在这一新背景下,结合国外灾害风险管理的研究,对洪水保险进行了有益的探索,针对以前我国洪水保险试点在农村地区失败的原因,提议我国应该从城市开始实施洪水保险计划,认为实施城市洪水保险有必要性和可行性,可以进一步拓展城市洪涝灾害风险管理的渠道。 相似文献
36.
37.
38.
This paper points to the need for seismic risk and vulnerability assessment of infrastructure systems, most notably tall structures and coastal facilities, in Kuwait and other Arabian Gulf countries. Building codes in the region currently lack seismic provisions, despite evidence of a potential threat from large-magnitude earthquakes originating from the southern part of the Zagros fold belt. The historical record of Iranian earthquakes that may have caused significant ground motion in the Gulf region is examined, as are reports of coastal damage from tsunamis. Various specific tasks, expected to constitute research priorities of a Joint Center for Risk Research, a cooperative research program involving Princeton and Kuwait Universities, are outlined. 相似文献
39.
Groundwater contamination: risk management and assessment for landfills in Mar del Plata, Argentina 总被引:3,自引:0,他引:3
This study presents a program for risk management in the contamination of groundwater resulting from leachate in landfills
at Mar del Plata (Argentina). The program includes prediction, prevention, monitory observation and mitigation as actions
that must be taken prior to, during, and after contamination occurs. This routine aids in the identification of weak points
and failures of the program for those who are in charge of making decisions, and will allow better use of limited financial
and technical resources based on planning, thus minimizing disconnected determinations.
Results of the prediction stage were confirmed through monitoring. The presence of a plume of contamination more than 100 m
from the landfill was shown, thus proving that implementation of a monitoring plan to follow the development of the contaminated
plume must be implemented, particularly in populated areas which depend on residential wells for their water supply.
Received: 8 May 2000 · Accepted: 14 August 2000 相似文献
40.