全文获取类型
收费全文 | 4798篇 |
免费 | 344篇 |
国内免费 | 293篇 |
专业分类
安全科学 | 541篇 |
废物处理 | 53篇 |
环保管理 | 687篇 |
综合类 | 1791篇 |
基础理论 | 332篇 |
污染及防治 | 221篇 |
评价与监测 | 1568篇 |
社会与环境 | 105篇 |
灾害及防治 | 137篇 |
出版年
2024年 | 20篇 |
2023年 | 79篇 |
2022年 | 139篇 |
2021年 | 126篇 |
2020年 | 182篇 |
2019年 | 109篇 |
2018年 | 98篇 |
2017年 | 144篇 |
2016年 | 180篇 |
2015年 | 215篇 |
2014年 | 271篇 |
2013年 | 321篇 |
2012年 | 338篇 |
2011年 | 363篇 |
2010年 | 261篇 |
2009年 | 261篇 |
2008年 | 179篇 |
2007年 | 270篇 |
2006年 | 253篇 |
2005年 | 238篇 |
2004年 | 174篇 |
2003年 | 236篇 |
2002年 | 143篇 |
2001年 | 145篇 |
2000年 | 129篇 |
1999年 | 93篇 |
1998年 | 71篇 |
1997年 | 87篇 |
1996年 | 70篇 |
1995年 | 45篇 |
1994年 | 43篇 |
1993年 | 40篇 |
1992年 | 19篇 |
1991年 | 16篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1980年 | 7篇 |
1979年 | 6篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1973年 | 2篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有5435条查询结果,搜索用时 15 毫秒
211.
212.
Longhurst J 《Environmental monitoring and assessment》2005,111(1-3):27-42
Denmark has a long tradition of monitoring the aquatic environment. Previous monitoring has mainly focused on loss of nutrients
and subsequent impacts on the biological structure in lakes and coastal areas. However, as part of the third Action Plan for
the Aquatic Environment more emphasis has been put on stream ecology. The present paper describes background, strategy and
content of the new NOVANA stream programme, which will run for the period 2004–2009. The new programme will encompass more
than 800 stations covering all stream types in Denmark and monitoring will include three biological quality elements (macrophytes,
macroinvertebrates and fish) as well as physico-chemical features and hydromorphological elements. In addition, the new programme
integrates monitoring of elements both in the stream itself and in the riparian zone. Compliance with important European Commission
Directives such as the Water Framework Directive and the Habitat Directive is discussed. 相似文献
213.
Wiersma YF 《Environmental monitoring and assessment》2005,100(1-3):1-9
Environmental benchmarks are widely used in Canadian environmental assessment as a standard against which to monitor air or water quality in response to human activities in the environment. Recent work in Canada has developed the concept of ecological benchmarks as a complement to environmental benchmarks. However, implementation of ecological benchmarks may be challenging. This paper presents an analogy between ecological benchmarks and the more commonly used environmental benchmarks, as an attempt to increase understanding and use of ecological benchmarks in resource management, assessment, and monitoring. Ecological benchmarks, and their corresponding indicators, will be challenging to identify and use. However, through the use of the principles of adaptive management, effective ecological indicators and benchmarks can be established. Although it is essential that ecological benchmarks are site-specific, the analogy and general principles outlined here are applicable to assessment and monitoring in any part of the world. 相似文献
214.
Graef F Schmidt G Schröder W Stachow U 《Environmental monitoring and assessment》2005,108(1-3):189-203
A representative environmental monitoring network at the regional scale cannot use raster-based or random sampling designs, but requires a stratified sampling procedure integrating different information layers, and it has to occur in ecologically differing homogeneous regions (ecoregions). These we have determined using a set of spatial strata with ecological variables which we analysed with classification and regression trees (CART). We present a framework for environmental monitoring, that covers different scales, and we transfer the framework to a potential GMO (genetically modified organisms) monitoring network. We use ecoregion and other environmental strata together with existing environmental monitoring networks to determine GMO monitoring sites more precisely. 相似文献
215.
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
216.
217.
利用面向对象技术、多线程技术和动态链接技术在嵌入式操作Windows CE上开发了移动环境监测系统。介绍了基于实时嵌入式操作的移动环境监测系统的设计原理、系统框架及关键技术。指出在嵌入式计算机上实现移动环境监测,既可以进行在线环境监测,也可以减少开发的费用和硬件投资。该系统的特点是集成度高,体积小,反应速度快,智能化高,稳定性好和可靠性强。 相似文献
218.
介绍了由数据采集与传输子系统、数据库子系统、水质预警预报子系统、数据输出子系统和人机交互界面组成的南水北调中线工程输水干线的水质监测管理信息系统,根据该系统的实际需求,阐述了开发该系统应该具备的关键技术。 相似文献
219.
论中国环境监测发展战略 总被引:23,自引:10,他引:23
介绍了中国环境监测的发展历程,分析了中国环境监测发展面临的压力,提出了中国环境监测的发展战略和实现战略目标的保障措施. 相似文献
220.
在开发全内反射荧光免疫传感器的基础上,研究水中微囊藻毒素-LR(MC-LR)的检测方法。建立了基于MC-LR平面波导免疫芯片的制备方法,并结合流动分析和荧光检测开发检测系统,针对MC-LR的免疫检测条件进行优化。结果表明,全内反射荧光免疫传感器对MC-LR抗体的检测限为0.001μg/mL;在间接竞争免疫检测模式下,最优检测条件是预反应时间5min、预反应温度37℃、进样停留时间500s;在最优检测条件下,对MC-LR的检测限为0.100μg/L,线性区间为0.200~4.000μg/L;全内反射荧光免疫传感器检测MC-LR的加标回收率均在100.0%±20.0%,平行测定的相对标准偏差小于5%。 相似文献