全文获取类型
收费全文 | 34646篇 |
免费 | 2640篇 |
国内免费 | 3839篇 |
专业分类
安全科学 | 5316篇 |
废物处理 | 587篇 |
环保管理 | 7672篇 |
综合类 | 16739篇 |
基础理论 | 3133篇 |
环境理论 | 62篇 |
污染及防治 | 1679篇 |
评价与监测 | 2643篇 |
社会与环境 | 2091篇 |
灾害及防治 | 1203篇 |
出版年
2024年 | 112篇 |
2023年 | 468篇 |
2022年 | 753篇 |
2021年 | 1038篇 |
2020年 | 1179篇 |
2019年 | 936篇 |
2018年 | 818篇 |
2017年 | 1235篇 |
2016年 | 1417篇 |
2015年 | 1476篇 |
2014年 | 1600篇 |
2013年 | 2137篇 |
2012年 | 2300篇 |
2011年 | 2518篇 |
2010年 | 1844篇 |
2009年 | 1984篇 |
2008年 | 1453篇 |
2007年 | 2218篇 |
2006年 | 2193篇 |
2005年 | 1917篇 |
2004年 | 1688篇 |
2003年 | 1585篇 |
2002年 | 1322篇 |
2001年 | 1173篇 |
2000年 | 1100篇 |
1999年 | 924篇 |
1998年 | 648篇 |
1997年 | 580篇 |
1996年 | 407篇 |
1995年 | 401篇 |
1994年 | 287篇 |
1993年 | 288篇 |
1992年 | 194篇 |
1991年 | 131篇 |
1990年 | 99篇 |
1989年 | 70篇 |
1988年 | 72篇 |
1987年 | 54篇 |
1986年 | 45篇 |
1985年 | 39篇 |
1984年 | 53篇 |
1983年 | 35篇 |
1982年 | 37篇 |
1981年 | 33篇 |
1980年 | 47篇 |
1979年 | 51篇 |
1978年 | 26篇 |
1973年 | 22篇 |
1972年 | 23篇 |
1971年 | 22篇 |
排序方式: 共有10000条查询结果,搜索用时 555 毫秒
131.
Benchmarking of environmental performance to demonstrate theachievement of best practice environmental management is acomponent of a new form of licensing of industrialdischarges in Western Australia. The paper describes theapproaches to benchmarking for the critical environmentalissues for an alumina refinery and wastewater treatmentplant. It also describes the lessons learnt from thebenchmarking process on appropriate methods, the benefitsand difficulties in the benchmarking process, and changesthat would assist benchmarking for best practiceenvironmental management. 相似文献
132.
The Prairie Adaptation Research Collaborative (PARC) has implemented an Internet Map Server (IMS) at the PARC web site (www.parc.ca) to 1) disseminate the geo-referenced results of PARC sponsored research on climate change impacts and adaptation, and 2) address data, information and knowledge management within the PARC network of researchers and partners. PARC facilitates interdisciplinary research on adaptation to the impacts of climate change in the Canadian Prairie Provinces. The web site is intended as a platform for sharing information and encouraging discussion of climate change impacts and adaptation. The IMS enables scientists and stakeholders to apply simple climate change scenarios to geo-referenced biophysical and social data, and dynamically create maps that display the geographic distribution of potential impacts of climate change. With a limited capacity for spatial analysis, most geo-processing and the climate impact modeling is done offline within a GIS environment. The IMS will serve the output from climate impact models, such that the model results can be customized by the web site user and be most readily applied to the planning and analysis of adaptation strategies. 相似文献
133.
A membrane extraction-gas chromatography method was developed fordetermination of organophosphorus pesticides and related compounds including methamidophos, DDVP, dimethoate, methyl parathion, parathion, thiophosphoric acid trimethyl ester, and thiophosphoramidic acid dimethyl ester in water samples. In thismethod, surface-modified acetic cellulose membranes were used to extract the target analytes in water samples, the extracted analytes were back-extracted into a small amount of methanol, andgas chromatography with pulsed flame photometric detector (GC-PFPD) was used to determine the concentrations of targetanalytes in the extracts. The recoveries obtained for thetarget analytes spiked into the water samples ranged from 66to 94%. The method detection limit for each target analyte was 0.05 g L-1. The method developed in this study had shown the advantages of being cheap, simple, fast, and reliable. It had been used successfully to determine the concentrations of target analytes in river water samples. 相似文献
134.
Sustainable development of the aquatic environment depends upon routine and defensible cumulative effects assessment (CEA). CEA is the process of predicting the consequences of development relative to an assessment of existing environmental quality. Theoretically, it provides an on-going mechanism to evaluate if levels of development exceed the environment's assimilative capacity; i.e., its ability to sustain itself. In practice, the link between CEA and sustainable development has not been realized because CEA concepts and methods have developed along two dichotomous tracks. One track views CEA as an extension of the environmental assessment (EA) process for project developments. Under this track, stressor-based (S-B) methods have been developed where the emphasis is on local, project-related stressors, their link with aquatic indicators, and the potential for environmental effects through stressor-indicator interactions. S-B methods focus on the proposed development and prediction of project-related effects. They lack a mechanism to quantify existing aquatic quality especially at scales broader than an isolated development. This limitation results in the prediction of potential effects relative to a poorly defined baseline state. The other track views CEA as a broader, regional assessment tool where effects-based (E-B) methods specialize in quantification of existing aquatic effects over broad spatial scales. However, the predictive capabilities of E-B methods are limited because they are retrospective, i.e., the stressor causing the effect is identified after the effect has been measured. When used in isolation, S-B and E-B methods do not address CEA in the context necessary for sustainable development. However, if the strengths of these approaches were integrated into a holistic framework for CEA, an operational mechanism would exist to better monitor and assess sustainable development of our aquatic resources. This paper reviews the existing conceptual basis of CEA in Canada including existing methodologies, limitations and strengths. A conceptual framework for integrating project-based and regional-based CEA is presented. 相似文献
135.
In this paper, the problem of optimal timing, when to adopt an environmental policy in a strategic framework is considered. Using real options theory and some basic tools of game theory, we show that, under certain assumptions, a country behaving strategically should wait longer before adopting such a policy than if it behaves unstrategically or within a larger entity. Such a postponed decision is sub-optimal as regards to the environment protection. 相似文献
136.
对室内装饰装修材料检测中甲醛分析方法的研究 总被引:2,自引:0,他引:2
目前室内装饰装修材料中甲醛含量的检测有六个类别,分析方法不统一,且没有一定的质量控制措施.文章对分析方法进行了改进,并且研究用水中的甲醛标样来对检测过程进行质量控制,结果较好. 相似文献
137.
138.
139.
Gałuszka A 《Environmental monitoring and assessment》2005,110(1-3):55-70
In June of 2000, biogeochemical study was carried out in three ecosystems of the Holy Cross Mountains (south-central Poland).
This paper presents element concentrations and stable sulfur (and in one site lead) isotope ratios in rocks, detailed soil
profiles, and plant bioindicators including epiphytic lichen Hypogymnia physodes (L.) Nyl., mosses (Pleurozium schreberi (Brid.) Mitt., Hypnum cupressiforme Hedw. S. Str., Hylocomium splendens (Hedw.) B.S.G.), Scots pine (Pinus sylvestris L.), common birch (Betula pendula Roth.), aspen (Populus tremula L.) and English oak (Quercus robur L.). Chemical analyses were performed with ICP-AES and AAS methods in the accredited laboratory (Central Chemical Laboratory
of the Polish Geological Institute in Warsaw). The principal objective of this study was to compare the chemical composition
of rocks, soils and selected plant bioindicators between investigation sites using the same methods of sample collection,
preparation and analyses. The results of this study have shown that there is a high variability in concentrations of elements
in plant bioindicators from the same sites that can not be explained only by soil properties or anthropogenic influence. This
conclusion indicates that for biomonitoring purposes (especially with vascular plants) we cannot neglect individual features
of the species examined. 相似文献
140.
Butter (45) and ghee (55) samples were collected from rural and urban areas of cotton growing belt of Haryana and analysed for detecting the residues of organochlorine, synthetic pyrethroid and organophosphate insecticides. The estimation was carried out by using multi residue analytical technique employing GC-ECD and GC-NPD systems equipped with capillary columns. Butter samples were comparatively more contaminated (97%) than ghee (94%), showing more contamination with organochlorine insecticides from urban samples. About 11% samples of butter showed endosulfan residues above MRL value and 2% samples had residues of synthetic pyrethroids and organophosphates each above their respective MRL values. In ghee, residues of HCH & DDT both and of endosulfan exceeded the MRL values in 5 and 20% samples, respectively. Among organophosphates, only chlorpyriphos was detected with 9% samples showing its residue above MRL value. Irrespective of contamination levels, residues above the MRL values were more in ghee. More extensive study covering other agricultural regions/zones of Haryana has been suggested to know the overall scenario of contamination of milk products. 相似文献