全文获取类型
收费全文 | 573篇 |
免费 | 14篇 |
国内免费 | 60篇 |
专业分类
安全科学 | 12篇 |
废物处理 | 7篇 |
环保管理 | 190篇 |
综合类 | 206篇 |
基础理论 | 104篇 |
污染及防治 | 72篇 |
评价与监测 | 33篇 |
社会与环境 | 20篇 |
灾害及防治 | 3篇 |
出版年
2023年 | 1篇 |
2022年 | 8篇 |
2021年 | 18篇 |
2020年 | 9篇 |
2019年 | 3篇 |
2018年 | 4篇 |
2017年 | 9篇 |
2016年 | 16篇 |
2015年 | 17篇 |
2014年 | 16篇 |
2013年 | 45篇 |
2012年 | 19篇 |
2011年 | 60篇 |
2010年 | 27篇 |
2009年 | 59篇 |
2008年 | 33篇 |
2007年 | 29篇 |
2006年 | 26篇 |
2005年 | 22篇 |
2004年 | 23篇 |
2003年 | 23篇 |
2002年 | 19篇 |
2001年 | 16篇 |
2000年 | 19篇 |
1999年 | 15篇 |
1998年 | 15篇 |
1997年 | 14篇 |
1996年 | 7篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 4篇 |
1992年 | 6篇 |
1991年 | 6篇 |
1990年 | 6篇 |
1989年 | 4篇 |
1988年 | 9篇 |
1987年 | 5篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 5篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1972年 | 1篇 |
排序方式: 共有647条查询结果,搜索用时 31 毫秒
1.
2.
浦东新区城市生态问题探析 总被引:3,自引:0,他引:3
以浦东新区为个案,提出了城市开发建设较为突出的城市平衡发展、河流治理、景观规划等方面的城市生态问题,并阐述了解决方法和对策。掌握并运用生态学原理,对于城市建设和管理具有重要意义。 相似文献
3.
4.
广东沿岸海域生物可利用性重金属的地理分布 总被引:6,自引:3,他引:6
利用牡蛎做监测生物,研究了广东沿岸海域生物可利用性重金属Cd,Cu和Zn的地理分布。牡蛎体的Cd,Cu和Zn含量存在着显著的地域差异,反映了广东沿岸海域生物可利用性的Cd,Cu和Zn在地域上存在很大的梯度。由牡蛎显示出的广东沿岸海域生物可利用性重金属的地理分布与广东沿岸海域受人为来源的重金属输入状况相一致,如实地反映了广东沿岸海域重金属污染的基本特征。 相似文献
5.
通过对秦山核电站运行前后相隔近7 a 的工程区邻近海域四季度月生物与非生物环境生态各要素的两次调查分析,进行了Ⅰ期工程运行以来海域生态环境及水质状况的影响评价。结果认为,秦山海域具典型强潮河口湾生态特征,营养盐丰富,而生产力低下。潮汐、径流和湾外海水入侵是导致海洋环境要素季节和年际变化并直接影响海洋生物结构的主要因子。水体富营养化指数上升是沿岸工业和生活污水大量排放的结果。核电站运行中冷却水的热排放由于杭州湾特殊的海底地形和强潮混合的水体环境对附近水域的热升温效应不明显。秦山Ⅰ期工程运行以来对海域生态环境和水质变化未见明显影响 相似文献
6.
以2000年和2004年的QuickBird卫星影像解译的徐径镇土地利用类型图为基础,对土地利用类型变化的幅度和土地利用类型之间转换的空间关系进行了研究,同时选取合适的景观格局指数对该区域的景观格局进行了分析。最后,给出结论和建议。 相似文献
7.
/ The valleys of European piedmonts constitute changing narrow corridors within which water, matter, nutrients, energy, and species flow. The dispersion patterns of these flows have been significantly disturbed since the end of the 18th century. Thus, western European valleys have been changed into complex mosaics by implementation of socioeconomical programs. In order to define future actions allowing the preservation of this "ecocomplex" (Blandin and Lamotte 1988), it is necessary to gather precise information of the landscape dynamics. Hence, the study of the European river valleys must be based upon two major steps: (1)the analysis of the present landscape with suitable remote sensing techniques, allowing us to map the complex mosaic of narrow corridors; and (2) the analysis of temporal landscape development patterns since the first engineering works that have transformed the braided channel system. In this paper, the efficiency of the addition of two techniques is highlighted: (1) the "wavelet merging method" from multispectral and panchromatic SPOT images for the floodplain land-cover mapping, and (2) the historical reconstruction techniques from old maps and archive documents in order to analyze the cumulative impacts of engineering works on landscape diversity. To illustrate the method, a particularly complex case study is chosen: the Arc/Isere confluence (downstream from Albertville, Savoie, France). Remote sensing, field survey, and historical reconstruction allowed us to distinguish two types of spatial units: (1) the "functional sets" characterized by independent state factors (edaphic, hydrological, and topographic) and supporting a limited number of vegetation types (spontaneous or cultivated), and (2) the functional unit (= ecotope), which corresponds to a unique combination of vegetation type/functional set.KEY WORDS: Landscape ecology; Floodplains; Vegetation; Land use; Remote sensing; Historical reconstruction; Mapping; Merging methods; Human impacts; Alps; Isere river; France 相似文献
8.
A pedagogic problem in forestry and landscape management is to visualize future landscape effects of forest growth and current management activities in the forest. This paper presents a method for forecasting digital image projections of forest landscape dynamics. Static nonlinear regression functions estimate the digital numbers in a Landsat Thematic Mapper image. Regressors used are forest stand variables. By estimating the future forest stand data, based on intermediate treatment and growth, future satellite digital images are created. In a case study example, the future landscape of a forest block in the province of Västernorrland, Sweden, is projected to demonstrate the application of this visualization technique. 相似文献
9.
Adaptive management: Promises and pitfalls 总被引:3,自引:1,他引:3
Proponents of the scientific adaptive management approach argue that it increases knowledge acquisition rates, enhances information flow among policy actors, and provides opportunities for creating shared understandings. However, evidence from efforts to implement the approach in New Brunswick, British Columbia, Canada, and the Columbia River Basin indicates that these promises have not been met. The data show that scientific adaptive management relies excessively on the use of linear systems models, discounts nonscientific forms of knowledge, and pays inadequate attention to policy processes that promote the development of shared understandings among diverse stakeholders. To be effective, new adaptive management efforts will need to incorporate knowledge from multiple sources, make use of multiple systems models, and support new forms of cooperation among stakeholders. 相似文献
10.
The New Jersey Toxics Reduction Workplan for Ny-Nj Harbor: Distribution of Pcdd/Fs in Ambient Waters
As part of the NJ Toxics Reduction Workplan for NY-NJ Harbor, ambient water samples were collected at fifteen locations along
the tidal portions of the Hackensack, Passaic, Raritan, Rahway and Elizabeth Rivers, and in Newark Bay, the Arthur Kill, and
Kill van Kull. A Trace Organics Platform Sampler was used to collect a total of 75 suspended sediment phase samples between
June 2000 and May 2002. These samples were analyzed for spatial and wet vs. dry weather trends in the 17 polychlorinated dibenzo-p-dioxins
and dibenzofurans (PCDD/Fs; modified USEPA Method 1613b). Mean total PCDD/F (tPCDD/F) concentrations at the sampling locations
ranged between 3.8 and 41.5 ng/g. On average, OCDD accounted for almost 80% of the tPCDD/F concentrations; mean total [PCDD/F
– OCDD] concentrations ranged between 0.84 and 5.20 ng/g at the sampling locations. Mean 2,3,7,8-TCDD concentrations ranged
between 0.003 and 0.28 ng/g, with the highest concentrations (> 0.10 ng/g) along the tidal Passaic and lower Hackensack Rivers,
and in upper Newark Bay. Mean tPCDD/F Toxic Equivalency Quotients (TEQ) ranged between 45 and 344 TEQ pg/g, with the highest
levels found in the lower Passaic River. Toxicity was primarily driven by 2,3,7,8-TCDD concentrations in the Passaic and Hackensack
Rivers, and in Newark Bay. Examples of congener distribution patterns at some of the sampling locations are also presented. 相似文献