全文获取类型
收费全文 | 2083篇 |
免费 | 161篇 |
国内免费 | 552篇 |
专业分类
安全科学 | 115篇 |
废物处理 | 14篇 |
环保管理 | 412篇 |
综合类 | 1287篇 |
基础理论 | 367篇 |
环境理论 | 3篇 |
污染及防治 | 134篇 |
评价与监测 | 169篇 |
社会与环境 | 203篇 |
灾害及防治 | 92篇 |
出版年
2024年 | 7篇 |
2023年 | 43篇 |
2022年 | 60篇 |
2021年 | 79篇 |
2020年 | 80篇 |
2019年 | 75篇 |
2018年 | 79篇 |
2017年 | 77篇 |
2016年 | 119篇 |
2015年 | 126篇 |
2014年 | 106篇 |
2013年 | 155篇 |
2012年 | 145篇 |
2011年 | 168篇 |
2010年 | 133篇 |
2009年 | 158篇 |
2008年 | 99篇 |
2007年 | 157篇 |
2006年 | 156篇 |
2005年 | 123篇 |
2004年 | 92篇 |
2003年 | 84篇 |
2002年 | 74篇 |
2001年 | 40篇 |
2000年 | 50篇 |
1999年 | 42篇 |
1998年 | 32篇 |
1997年 | 19篇 |
1996年 | 24篇 |
1995年 | 26篇 |
1994年 | 21篇 |
1993年 | 25篇 |
1992年 | 19篇 |
1991年 | 12篇 |
1990年 | 9篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 4篇 |
1983年 | 3篇 |
1982年 | 7篇 |
1981年 | 8篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1975年 | 3篇 |
1973年 | 2篇 |
1972年 | 9篇 |
1971年 | 5篇 |
1970年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有2796条查询结果,搜索用时 15 毫秒
21.
Macroinvertebrate Regionalisation for use in the Management of Aquatic Ecosystems in Victoria, Australia 总被引:5,自引:0,他引:5
The development of a broader, more holistic approach to aquaticecosystem management has been called for in recent years. Physical and chemical objectives alone are no longer consideredsufficient for the protection of aquatic ecosystems and shouldbe supplemented with biological objectives. The ubiquitousand sedentary nature of macroinvertebrates, combined with theirmeasurable response to environmental conditions, favour their use as important indicators in environmental policies. To establish biological objectives, there is a need for a regionalframework to limit the variability between ecosystems. Past studies have demonstrated that an a posteriori regionalisationapproach may be more useful than an a priori approach in explaining single component (e.g. macroinvertebrates) patternsacross ecosystems. This is particularly important as aquaticresource management agencies often focus on one or twocomponents of the ecosystem to assess environmental health. This study uses an a posteriori method to delineate and describebiological regions based on edge and riffle macroinvertebrate data. The regionalisation will provide a framework for settingbiological objectives, based on the range of reference conditionsmeasured within each separate region. The objectives will includeregional checklists for taxa and biotic indices. Predictive modelling in the style of RIVPACS or AUSRIVAS will also be usedwithin each region to develop objectives, incorporating local, regional and systematic features as predictor variables. 相似文献
22.
Ambient Air Quality Monitoring Network Design for Assessing Human Health Impacts from Exposures to Airborne Contaminants 总被引:1,自引:0,他引:1
Existing methods of establishing ambientair quality monitoring networks typically evaluateonly parameters related to ambient concentrations ofthe contaminant(s) of interest such as emissionsource characteristics, atmospheric transport anddispersion, secondary reactions, depositioncharacteristics, and local topography. However,adverse health risks from exposures to airbornecontaminants are a function of the contaminant andthe anatomic and physiologic characteristics of theexposed population. Thus, ambient air qualitymonitoring networks designed for the protection ofpublic health or for epidemiological studiesevaluating adverse health impacts from exposures toambient air contaminants should account for bothcontaminant characteristics and human healthparameters. A methodology has been establishedwhich optimizes ambient air quality monitoringnetworks for assessments of adverse human healthimpacts from exposures to airborne contaminants byincorporating human health risk assessmenttechniques. The use of risk assessment techniquesas the basis for designing ambient air qualitymonitoring networks will help to target limitedfinancial and human resources to evaluate humanhealth risks from exposures to airbornecontaminants. 相似文献
23.
跨界河流的水质监测(1) 总被引:2,自引:1,他引:2
水质监测是任何水资源管理必不可少的组成部分,水质监测与评价不仅可对水污染问题进行鉴别和评估,而且可以验证污染控制措施是否正确以及污染源是否遵守了相关的环保法规、制度、文章讨论了综合监测系统的对策、网络设计、采样与分析、数据处理与报告,还讨论了必需的科学的组织形式。以4条跨界河流[欧洲的莱茵河(Rhine)和多瑙河(Danube)、南美的拉普拉塔河(La Plata)、东南亚的湄公河(Mekong)]为例阐述了现代意义的监测方法学。对于工业化程度高的流域(如莱茵河和多瑙河),早期预警系统尤为重要。最后探讨了新的性价比好的污染监测方法以及如何避免产生数据很多,但信息量很少的状况。 相似文献
24.
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
25.
26.
根据自然地理、海洋动力、生物等特征!本文研究受大河作用的大丰潮滩地貌、沉积过程,讨论老黄河和长江对该潮滩发育的影响和潮滩生物群落空间分布及演变规律。本文评价了大丰潮滩开发利用现状,分析了它们的经济效益和环境效益,提出把目前受到强烈改造、过度利用的模式改变为顺应潮滩自然演变、有步骤合理开发利用潮滩的模式。 相似文献
27.
28.
29.
30.
作者前文所建立的狭窄海湾潮交换的分段模式的合理性由矩形海湾数值计算结果得到验证,并被应用于象山港海湾水的更新周期估算 相似文献