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301.
Environmental impact assessment using FORM and groundwater system reliability concept: case study Jining, China 总被引:2,自引:0,他引:2
In this paper, fist-order reliability method (FORM) is used to evaluate the impacts of uncertainties posed by traditional
deterministic models on the environment in Jining, China. Because of groundwater contamination in shallow aquifer, and an
increase in water demand, the new wells target the confined aquifer with constant pumping rate of 5,000 m3/d. Using Theis equation, the groundwater drawdown is analyzed to determine whether the confined aquifer will be contaminated.
Although the piezometric level is higher than the phreatic level by 11.0 m, the risk of drawdown is still 19.49% when the
pumping rate of 5,000 m3/d is maintained for 2 years. The deterministic model indicates a drawdown of 8.94 m which is lower than the maximum tolerance
drawdown of 11.0 m. The sensitivity and uncertainty analysis reveal that the model result is more sensitive to transmissivity
than specific yield, while the reliability analysis offers significant information for the decision makers. This approach
exposes and minimizes the risk of undesirable consequences such as groundwater contamination. 相似文献
302.
Landslide risk assessment using concepts of danger pixels and fuzzy set theory in Darjeeling Himalayas 总被引:4,自引:1,他引:3
Landslide risk assessment (LRA) is a key component of landslide studies. The landslide risk can be defined as the potential
for adverse consequences or loss to human population and property due to the occurrence of landslides. The LRA can be regional
or site-specific in nature and is an important information for planning various developmental activities in the area. LRA
is considered as a function of landslide potential (LP) and resource damage potential (RDP). The LP and RDP are typically
characterized by the landslide susceptibility zonation map and the resource map (i.e., land use land cover map) of the area,
respectively. Development of approaches for LRA has always been a challenge. In the present study, two approaches for LRA,
one based on the concept of danger pixels and the other based on fuzzy set theory, have been developed and implemented to
generate LRA maps of Darjeeling Himalayas, India. The LRA map based on the first approach indicates that 1,015 pixels of habitation
and 921 pixels of road section are under risk due to landslides. The LRA map derived from fuzzy set theory based approach
shows that a part of habitat area (2,496 pixels) is under very high risk due to landslides. Also, another part of habitat
area and a portion of road network (7,204 pixels) are under high risk due to landslides. Thus, LRA map based on the concept
of danger pixels gives the pixels under different resource categories at risk due to landslides whereas the LRA map based
on the concept of fuzzy set theory further refines this result by defining the degree of severity of risk to these categories
by putting these into high and low risk zones. Hence, the landslide risk assessment study carried out using two approaches
in this paper can be considered in cohesion for assessing the risks due to landslides in a region. 相似文献
303.
Successful adaptation to climate risks will depend on the outcomes of many coordinated and uncoordinated actions. Key will be ensuring public and private adaptations undertaken at a variety of scales do not undermine one another. To improve understandings of how adaptive responses accumulate, we investigate interactions between public and private efforts to mitigate flood hazards in the Deerfield River Watershed, located in Western Massachusetts, USA. Through interviews, we uncover the manner in which private adaptations, undertaken by landowners seeking to protect their land from flood impacts, are both determined in response to and have an effect on public adaptations seeking to address flood impacts across the watershed. Landowners respond to public adaptations based on their perceptions of the appropriateness of adaptive pathways including how they view the effectiveness of adaptive action and how the actions fit with the social contract. As a result, the interface between public and private adaptations takes various forms: commutable, attenuating, synergistic, or countervailing. Our findings underscore how, in areas with high geo-physical connectivity and where responsibility is dispersed across private and public entities, anticipating and responding to multiple interfaces between public and private adaptations is needed for public adaptations to achieve the best cumulative outcomes. 相似文献
304.
This paper focuses on how scientific uncertainties about future peak flood flows and sea level rises are accounted for in long term strategic planning processes to adapt inland and coastal flood risk management in England to climate change. Combining key informant interviews (n = 18) with documentary analysis, it explores the institutional tensions between adaptive management approaches emphasising openness to uncertainty and to alternative policy options on the one hand and risk-based ones that close them down by transforming uncertainties into calculable risks whose management can be rationalized through cost-benefit analysis and nationally consistent, risk-based priority setting on the other hand. These alternative approaches to managing uncertainty about the first-order risks to society from future flooding are shaped by institutional concerns with managing the second-order, ‘institutional’ risks of criticism and blame arising from accountability for discharging those first-order risk management responsibilities. In the case of river flooding the poorly understood impacts of future climate change were represented with a simplistic adjustment to peak flow estimates, which proved robust in overcoming institutional resistance to making precautionary allowances for climate change in risk-based flood management, at least in part because its scientific limitations were acknowledged only partially. By contrast in the case of coastal flood risk management, greater scientific confidence led to successively more elaborate guidance on how to represent the science, which in turn led to inconsistency in implementation and increased the institutional risks involved in taking the uncertain effects of future sea level rise into account in adaptation planning and flood risk management. Comparative analysis of these two cases then informs some wider reflections about the tensions between adaptive and risk-based approaches, the role of institutional risk in climate change adaptation, and the importance of such institutional dynamics in shaping the framing uncertainties and policy responses to scientific knowledge about them. 相似文献
305.
基于临界条件的中国航空气象危险要素区域分布与风险区划 总被引:2,自引:1,他引:1
根据航空飞行安全的气象保障规范和临界条件,探讨了我国区域内影响飞机起降的气象要素的区域特征;在气象要素影响分析的基础上,建立飞机起降安全的气象要素评价指标;采用层次分析法(AHP)确定各评价指标的权重,利用模糊综合评价方法构建了飞机起降气象安全风险的评价标准和评价体系,运用区间梯形隶属度函数来计算评估单元各指标针对各风险等级的隶属度,最后根据最大隶属度原则作出风险评估与区划。分析表明,我国北方地区航空安全气象环境较南方地区好,南方出现航空飞行不利影响的恶劣气象条件的频率显著高于北方;我国航空安全气象风险由北至南逐渐递增,尤以东部沿海地区、福建和江西东北部地区、贵州东部及湖南地区的风险等级最高。 相似文献
306.
307.
Chao Chen Kate Z. Guyton 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(4):487-494
The objectives of this paper are to (1) reexamine the data that were used to support the conclusion of a threshold effect
for 2-amino-3,8-dimethylimidazo[4,5-f] quinoxaline (MeIQx)-induced initiation and carcinogenicity at low doses in the rat
liver, and (2) discuss issues and uncertainties about assessing cancer risk at low doses. Our analysis is part of an effort
to understand proper interpretation and modeling of data related to cancer mechanisms and is not an effort to develop a risk
assessment for this compound. The data reanalysis presented herein shows that the low-dose initiation activity of MeIQx, which
can be found in cooked meat, cannot be dismissed. It is argued that the threshold effect for carcinogenic agents cannot be
determined by statistical non-significance alone; more relevant biological information is required. A biologically motivated
procedure is proposed for data analyses. The concept and procedure that are appropriate for analyzing MeIQx data are equally
applicable to other compounds with comparable data.
The ideas and approaches in this presentation are those of the authors and do not necessarily represent the positions or policies
of the USEPA. 相似文献
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