全文获取类型
收费全文 | 269篇 |
免费 | 30篇 |
国内免费 | 14篇 |
专业分类
安全科学 | 96篇 |
废物处理 | 1篇 |
环保管理 | 33篇 |
综合类 | 77篇 |
基础理论 | 42篇 |
污染及防治 | 5篇 |
评价与监测 | 17篇 |
社会与环境 | 17篇 |
灾害及防治 | 25篇 |
出版年
2023年 | 4篇 |
2022年 | 5篇 |
2021年 | 17篇 |
2020年 | 11篇 |
2019年 | 18篇 |
2018年 | 12篇 |
2017年 | 21篇 |
2016年 | 11篇 |
2015年 | 10篇 |
2014年 | 8篇 |
2013年 | 18篇 |
2012年 | 15篇 |
2011年 | 17篇 |
2010年 | 16篇 |
2009年 | 16篇 |
2008年 | 8篇 |
2007年 | 18篇 |
2006年 | 7篇 |
2005年 | 13篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 2篇 |
2001年 | 10篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 2篇 |
1996年 | 5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313条查询结果,搜索用时 15 毫秒
301.
水资源评价图是一种既传统又崭新的评价结果表现形式,它以可视化方式来反映水资源的特点和规律,具有直观形象等特点,是利用和保护水资源科学决策的基本手段。3S技术已经在很多领域得到了广泛的发展和应用,根据水资源评价图研究现状和特点确定3S技术在制作流域水资源图中可行性。以湖北省漳河流域水资源评价系列图的制作为例,提出了3S技术支持下评价图制作的程序,分析了3S技术支持下水资源评价图制作的具体内容、方法及3S在评价图制作中的关键作用,RS和GIS结合可以更好地实现数据的插补,GPS和GIS结合可以获取精度更高的定位数据,符号库的扩充可以更客观、形象地展示评价结果,最后指出这种方法相对于传统手工制图的优点,是规划图件制作的必然趋势。 相似文献
302.
为评估制造业对纳污水体有机物的污染影响,了解污染河道中有机物的种类、含量及赋存特性,采用极性和非极性逐步分离的方法对广东佛山市顺德区容桂街道内河涌沉积物中的有机物进行了综合的物理图谱解析研究.结果表明,污染沉积物中共检出包括烷烃类、烯烃类、多环芳烃、苯系物、杂环类、邻苯二甲酸酯类、醛酮、极性化合物、含硅物质以及烷酸酯类等10大类有机污染物共171种.按检出污染物种类的数量分析,烷烃类>极性化合物>多环芳烃>醛酮类>杂环>苯系物、邻苯二甲酸酯类>烷酸酯类>含硅物质>烯烃.按照有机物相对丰度分析,烷烃类>极性化合物>烷酸酯类>烯烃类>多环芳烃>邻苯二甲酸酯类>含硅物质>醛酮>杂环类>苯系物.在相对含量最高的烷烃类有机污染物中,十九烷在同类物质中占比高达14.83%.毒害性持久性有机污染物多环芳烃的总有机物占比为2.33%,检测中还发现大量有机醇、酚等和涂料工业,邻苯二甲酸酯类等塑料工业以及和电子工业产业相关的有机硅类等物质.和同类研究相比,该区域检出51种、占总有机物55.5%丰度的烷烃类物质种类更丰富,含量更高.本研究对制造业纳污河涌沉积物的有机污染物分析研究,为同质污染河涌的污染治理提供参考. 相似文献
303.
以武汉市后官湖地区为例,采用层次分析法(AHP)测试了人们对该区域内3种景观类型、12类景观元素的认知偏好情况,并初步分析了景观认知偏好的人群差异性。结果表明:(1)样本人群对不同的景观类型和景观元素表现出不同程度的偏好,并且普遍偏好自然景观(尤其是包含水体和与树木有关的景观元素),其次是半自然景观,最次是人工景观;(2)不同个体对于自然景观的认知偏好表现出明显的差异性,而对于人工景观,样本人群的认知偏好评价较为一致;(3)样本人群的性别、年龄、地区、受教育程度、职业及专业背景均会对个体的景观认知偏好产生不同程度的影响,影响程度从大到小依次为:年龄、职业、地区、专业背景、受教育程度、性别;(4)通过对样本人群个体差异性分析结果,最为偏好自然景观的人群大致具有以下特征:女性、小于45岁、居住在城市地区、大学及以上受教育程度、从事室内工作、具有景观或设计相关专业知识。 相似文献
304.
305.
Sebastián Corral David Sáez Gislaine Lam Patricia Lillo Rodrigo Sandoval Domingo Lancellotti 《毒物与环境化学》2013,95(2):344-358
It is widely known that human exposure to mercury vapor can cause neurological and neuropsychological deterioration. We have investigated if a population of Chilean artisanal gold-mining workers heavily exposed to elemental mercury (Hg0) display neurological and neuropsychological impairment. Male volunteers occupationally exposed to Hg0 (“gold miners”, n = 35) were recruited and compared with a group of unexposed workers (n = 40). Blood specimens were obtained from both groups for total mercury quantification. Upon neurological examination, 71% of the “gold miners” group showed abnormalities expressed as frontal impairment, tremor, or simultaneously frontal impairment, parkinsonism, and pyramidal syndrome. In contrast, only 16% of the individuals in the control group displayed neurological abnormalities. The “gold miners” group also showed impairment of the neuropsychological performance and the distribution of abnormal scores for almost all the neuropsychological tests applied was significantly higher in this group compared to the control group. Educational level, alcohol intake, and smoking habits did not influence the outcome of the neurological or neuropsychological examinations. Finally, despite that the higher blood mercury concentrations were found in the “gold miners” group, they were not significantly different from the values obtained in the control group. 相似文献
306.
Applications of artificial neural networks for patterning and predicting aquatic insect species richness in running waters 总被引:3,自引:0,他引:3
Two artificial neural networks (ANNs), unsupervised and supervised learning algorithms, were applied to suggest practical approaches for the analysis of ecological data. Four major aquatic insect orders (Ephemeroptera, Plecoptera, Trichoptera, and Coleoptera, i.e. EPTC), and four environmental variables (elevation, stream order, distance from the source, and water temperature) were used to implement the models. The data were collected and measured at 155 sampling sites on streams of the Adour–Garonne drainage basin (South-western France). The modelling procedure was carried out following two steps. First, a self-organizing map (SOM), an unsupervised ANN, was applied to classify sampling sites using EPTC richness. Second, a backpropagation algorithm (BP), a supervised ANN, was applied to predict EPTC richness using a set of four environmental variables. The trained SOM classified sampling sites according to a gradient of EPTC richness, and the groups obtained corresponded to geographic regions of the drainage basin and characteristics of their environmental variables. The SOM showed its convenience to analyze relationships among sampling sites, biological attributes, and environmental variables. After accounting for the relationships in data sets, the BP used to predict the EPTC richness with a set of four environmental variables showed a high accuracy (r=0.91 and r=0.61 for training and test data sets respectively). The prediction of EPTC richness is thus a valuable tool to assess disturbances in given areas: by knowing what the EPTC richness should be, we can determine the degree to which disturbances have altered it. The results suggested that methodologies successively using two different neural networks are helpful to understand ecological data through ordination first, and then to predict target variables. 相似文献
307.
Colleen Burch Johnson T.J. Sullivan D.J. Buck 《Journal of the American Water Resources Association》1989,25(3):565-572
ABSTRACT: Topographic maps are commonly used to define populations of lakes in regional surveys of surface water quality. To illustrate the effect of different maps on that process, we compared the lakes represented on the 1:250,000-scale maps used for the Northeast Region of the Eastern Lake Survey—Phase I (ELS-I) to the lakes on a sample of large-scale maps (1:24,000 or 1:62,500). Lake areas at or near the lower limit of representation delimited “smallest-lake” values for the compared 1:250,000-scale maps. The regional median for these values was 4.5 hectares (ha) and ranged from 0.6 to 24.8 ha. Lake representation is influenced by cartographic limitations such as map scale, age, and complexity as well as the inherent variability of waterbodies (e.g., water level fluctuations or the creation of reservoirs, beaver impoundments, and oxbows). The total number of lakes on large-scale maps increased markedly as lake area decreased. Approximately 15,700 of the estimated 29,000 lakes in the EPA's Northeast Region were 1 to 4 ha in area. Because maps affect the size distribution of lakes included in a regional survey and because lake areas are thought to modify lake chemistry, maps ultimately affect the estimates of regional surface water quality. 相似文献
308.
Joseph K. Berry 《Environmental management》1987,11(3):317-325
The growing use of computers in environmental management is profoundly changing data collection procedures, analytic processes, and even the decision-making environment itself. The emerging technology of geographic information systems (GIS) is expanding this revolution to integrate spatial information fully into research, planning, and management of land. In one sense, this technology is similar to conventional map processing involving traditional maps and drafting aids, such as pens, rub-on shading, rulers, planimeters, dot grids, and acetate sheets for light-table overlays. In another sense, these systems provide advanced analytic capabilities, enabling managers to address complex issues in entirely new ways. This report discusses a fundamental approach to computer-assisted map analysis that treats entire maps as variables. The set of analytic procedures for processing mapped data forms a mathematical structure analogous to traditional statistics and algebra. All of the procedures discussed are available for personal computer environments. 相似文献
309.
Web-based GIS for collaborative planning and public participation: an application to the strategic planning of wind farm sites 总被引:2,自引:0,他引:2
Spatial planning typically involves multiple stakeholders. To any specific planning problem, stakeholders often bring different levels of knowledge about the components of the problem and make assumptions, reflecting their individual experiences, that yield conflicting views about desirable planning outcomes. Consequently, stakeholders need to learn about the likely outcomes that result from their stated preferences; this learning can be supported through enhanced access to information, increased public participation in spatial decision-making and support for distributed collaboration amongst planners, stakeholders and the public. This paper presents a conceptual system framework for web-based GIS that supports public participation in collaborative planning. The framework combines an information area, a Multi-Criteria Spatial Decision Support System (MC-SDSS) and an argumentation map to support distributed and asynchronous collaboration in spatial planning. After analysing the novel aspects of this framework, the paper describes its implementation, as a proof of concept, in a system for Web-based Participatory Wind Energy Planning (WePWEP). Details are provided on the specific implementation of each of WePWEP's four tiers, including technical and structural aspects. Throughout the paper, particular emphasis is placed on the need to support user learning throughout the planning process. 相似文献
310.