全文获取类型
收费全文 | 196篇 |
免费 | 19篇 |
国内免费 | 17篇 |
专业分类
安全科学 | 28篇 |
废物处理 | 2篇 |
环保管理 | 29篇 |
综合类 | 73篇 |
基础理论 | 43篇 |
污染及防治 | 5篇 |
评价与监测 | 16篇 |
社会与环境 | 13篇 |
灾害及防治 | 23篇 |
出版年
2023年 | 3篇 |
2022年 | 3篇 |
2021年 | 13篇 |
2020年 | 8篇 |
2019年 | 8篇 |
2018年 | 5篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 6篇 |
2014年 | 4篇 |
2013年 | 7篇 |
2012年 | 11篇 |
2011年 | 14篇 |
2010年 | 11篇 |
2009年 | 15篇 |
2008年 | 8篇 |
2007年 | 12篇 |
2006年 | 4篇 |
2005年 | 11篇 |
2004年 | 8篇 |
2003年 | 9篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 5篇 |
1987年 | 1篇 |
排序方式: 共有232条查询结果,搜索用时 31 毫秒
121.
Antonopoulos IS Karagiannidis A Gkouletsos A Perkoulidis G 《Waste management (New York, N.Y.)》2012,32(4):710-718
A non-stoichiometric model for a downdraft gasifier was developed in order to simulate the overall gasification process. Mass and energy balances of the gasifier were calculated and the composition of produced syngas was predicted. The capacity of the modeled gasifier was assumed to be 0.5 MW, with an Equivalence Ratio (EQ) of 0.45. The model incorporates the chemical reactions and species involved, while it starts by selecting all species containing C, H, and O, or any other dominant elements. Olive wood, miscanthus and cardoon were tested in the formulated model for a temperature range of 800-1200 °C, in order to examine the syngas composition and the moisture impact on the supplied fuel. Model results were then used in order to design an olive wood gasification reactor. 相似文献
122.
David W. Watkins Greg A. Link Dennis Johnson 《Journal of the American Water Resources Association》2005,41(1):157-170
ABSTRACT: For regional precipitation frequency analyses, methods are needed to spatially interpolate or smooth point intensity duration frequency (IDF) estimates at gage sites for the purposes of visualization and estimation at ungaged sites. In this study to update IDF estimates for Michigan, the assumption is made that for practical purposes, the entire state may be treated as a homogeneous region in which annual maximum precipitation is identically distributed at each site apart from a site‐specific scaling factor, commonly known as the index flood. Several interpolation and smoothing techniques are evaluated for IDF estimation at ungaged sites, including trend surface analysis, thin plate splines, inverse distance weighting, and several kriging algorithms. Ordinary block kriging is recommended as a practical and objective method for smoothing the variability in the index flood values and developing isopluvial maps. 相似文献
123.
自然灾害软风险区划图模式研究 总被引:2,自引:0,他引:2
如何表达风险值估计不准,是深层次风险区划研究的问题.将模糊风险研究引向自然灾害风险区划领域,探讨了风险值估计不准条件下自然灾害风险区划的图型模式.给出了一种带有“层次“结构的“多值的“的自然灾害风险区划图图型模式.这是应用软计算的思想和方法得到的一种自然灾害风险区划图,我们称之为自然灾害软风险区划图.自然灾害软风险区划图不仅提供了表达风险值估计不准这一信息,而且提供了风险信息的可靠性,为改进自然灾害风险区划提供一种新的思路. 相似文献
124.
姚清林 《防灾减灾工程学报》1996,(4)
在紧急地震救灾期往往来不及优选通往现场的最短路径,由于地震破坏城市的交通系统,改变其可通行性,震前又不能按照静态的最短路算法进行设计。因此,本文在进行路径可通行性破坏概率预测与控制的基础上,给出了为重点救灾目标设计最佳安全度最短路径的图与网络算法 相似文献
125.
Self-Organizing Maps for Integrated Environmental Assessment of the Mid-Atlantic Region 总被引:6,自引:0,他引:6
A new method has been developed to perform environmental assessment at regional scale. This involves a combination of a self-organizing map (SOM) neural network and principal component analysis (PCA). The method is capable of clustering ecosystems in terms of environmental conditions and suggesting relative cumulative environmental impacts of multiple factors across a large region. Using data on land-cover, population, roads, streams, air pollution, and topography of the Mid-Atlantic region, the method was able to indicate areas that are in relatively poor environmental condition or vulnerable to future deterioration. Combining the strengths of SOM with those of PCA, the method offers an easy and useful way to perform a regional environmental assessment. Compared with traditional clustering and ranking approaches, the described method has considerable advantages, such as providing a valuable means for visualizing complex multidimensional environmental data at multiple scales and offering a single assessment or ranking needed for a regional environmental assessment while still facilitating the opportunity for more detailed analyses. 相似文献
126.
Can machines recognise stress in plants? 总被引:2,自引:0,他引:2
Ronald?Maldonado-RodriguezEmail author Stancho?Pavlov Alberto?Gonzalez Abdallah?Oukarroum Reto?J.?Strasser 《Environmental Chemistry Letters》2003,1(3):201-205
In this paper we show that chlorophyll a fluorescence signals analysed with the self-organizing map (SOM) can be used as a routine tool for the monitoring and classification of pea varieties (Pisum sativum) according to their degree of resistance against drought stress. Fluorescence kinetics measurements were obtained from non-stressed plants. The aim of this study is to evaluate the applicability of artificial intelligence techniques in eco-physiological research. Our goal is to provide a fast tool that will contribute to the knowledge needed to develop strategies that would help to decrease the impact of environmental stress in agriculture and forestry. 相似文献
127.
中国建筑抗震设计规范的演变与展望 总被引:9,自引:3,他引:9
陈国兴 《防灾减灾工程学报》2003,23(1):102-113
地震区划图是编制抗震设计规范的基础资料。本文回顾了中国地震区划图和建筑抗震设计规范的发展简史,对1 956、1977、1990和2001年编制的中国地震区划图进行了简要比较,指出了4代区划图的差异;对1959、1964、1974、1989和2002年编制的中国建筑抗震设计规范或草案的抗震设计原则进行了比较,详细比较了5部规范或草案中关于地震作用的计算方法、场地分类和地基抗震有关规定的异同点,简要讨论了建筑抗震设计规范的发展方向。 相似文献
128.
Comparing Landslide Maps: A Case Study in the Upper Tiber River Basin, Central Italy 总被引:17,自引:0,他引:17
/ The preparation of landslide maps is an important step in any landslide hazard assessment. Landslides maps are prepared around the world, but little effort is made to assess their reliability, outline their main characteristics, and pinpoint their limitations. In order to redress this imbalance, the results of a long-term research project in the Upper Tiber River basin in central Italy are used to compare reconnaissance and detailed landslide inventory maps, statistical and geomorphologically based density maps, and landslide hazard maps obtained by multivariate statistical modeling. An attempt is made to discuss advantages and limitations of the available maps, outlining possible applications for decision-makers, land developers, and environmental and civil defence agencies. The Tiber experiment has confirmed that landslides can be cost-effectively mapped by interpreting aerial photographs coupled with field surveys and that errors and uncertainties associated with the inventory can be quantified. The experiment has shown that GIS makes it easy to prepare landslide density maps and facilitates the production of statistically based landslide hazard models. The former supply an overview of the distribution of landslides that is easily comprehended but do not provide insight on the causes of instability. The latter, giving insight into the causes of instability, are diagnostically powerful, but are difficult to prepare and exploit. 相似文献
129.
130.