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81.
通过采用SBR改良工艺处理城乡结合部生活污水的试验,根据城乡结合部污水的特点,采用SBR改良工艺,研究工艺的处理效果、水量波动和排水位置对处理效果的影响。结果表明,SBR改良工艺对城乡结合部污水有良好的处理效果;SBR改良工艺耐冲击负荷能力大,在连续2倍进水量的情况下,仍有良好的处理效果;降低排水位置对出水SS有一定的影响,但SBR工艺的污泥沉降效果好。  相似文献   
82.
With the aim of wood production with negligible negative effects on biodiversity and ecosystem processes, a silvicultural practice of selective logging with natural regeneration has been implemented in European beech forests (Fagus sylvatica) during the last decades. Despite this near‐to‐nature strategy, species richness of various taxa is lower in these forests than in unmanaged forests. To develop guidelines to minimize the fundamental weaknesses in the current practice, we linked functional traits of saproxylic beetle species to ecosystem characteristics. We used continental‐scale data from 8 European countries and regional‐scale data from a large forest in southern Germany and forest‐stand variables that represented a gradient of intensity of forest use to evaluate the effect of current near‐to‐nature management strategies on the functional diversity of saproxylic beetles. Forest‐stand variables did not have a statistically significant effect on overall functional diversity, but they did significantly affect community mean and diversity of single functional traits. As the amount of dead wood increased the composition of assemblages shifted toward dominance of larger species and species preferring dead wood of large diameter and in advanced stages of decay. The mean amount of dead wood across plots in which most species occurred was from 20 to 60 m3/ha. Species occurring in plots with mean dead wood >60 m3/ha were consistently those inhabiting dead wood of large diameter and in advanced stages of decay. On the basis of our results, to make current wood‐production practices in beech forests throughout Europe more conservation oriented (i.e., promoting biodiversity and ecosystem functioning), we recommend increasing the amount of dead wood to >20 m3/ha; not removing dead wood of large diameter (50 cm) and allowing more dead wood in advanced stages of decomposition to develop; and designating strict forest reserves, with their exceptionally high amounts of dead wood, that would serve as refuges for and sources of saproxylic habitat specialists. Efectos Actuales del Manejo Casi Natural de Bosques sobre la Composición de Atributos Funcionales de Escarabajos Saproxílicos en Bosques de Haya  相似文献   
83.
Abstract:  Applying the ecosystem services concept to conservation initiatives or in managing ecosystem services requires understanding how environmental impacts affect the ecology of key species or functional groups providing the services. We examined effects of river impoundments, one of the leading threats to freshwater biodiversity, on an important ecosystem service provided by large tropical rivers (i.e., artisanal fisheries). The societal and economic importance of this ecosystem service in developing countries may provide leverage to advance conservation agendas where future impoundments are being considered. We assessed impoundment effects on the energetic costs of fisheries production (embodied energy) and commercial market value of the artisanal fishery of the Paraná River, Brazil, before and after formation of Itaipu Reservoir. High-value migratory species that dominated the fishery before the impoundment was built constituted a minor component of the contemporary fishery that is based heavily on reservoir-adapted introduced species. Cascading effects of river impoundment resulted in a mismatch between embodied energy and market value: energetic costs of fisheries production increased, whereas market value decreased. This was partially attributable to changes in species functional composition but also strongly linked to species identities that affected market value as a result of consumer preferences even when species were functionally similar. Similar trends are expected in other large tropical rivers following impoundment. In addition to identifying consequences of a common anthropogenic impact on an important ecosystem service, our assessment provides insight into the sustainability of fisheries production in tropical rivers and priorities for regional biodiversity conservation .  相似文献   
84.
The authors analysed a proportional valve with electrical position feedback for its failure behaviour. Severalfailures were introduced into the feedback loop, especially into the 2 solenoids and the inductive positiontransducer. The behaviour of the valve for square and ramp reference signals was recorded and systematicallyanalysed. It was shown that failures could be detected by monitoring the residual signal from the equipmentunder control or the residual signal from the sensor. It was possible to achieve the safe position within twice thenormal response time of the valve by switching off the current of both solenoids. The application of these resultsfor a new generation of safe proportional valves is discussed. The use of the results of these investigationsobviates the need for redundancy of the electrical position monitoring arrangement in a safe proportionalvalve.  相似文献   
85.
86.
Genetic modification leads to several important moral issues. Up until now they have mainly been discussed from the viewpoint that only individual living beings, above all animals, are morally considerable. The standpoint that also collective entities such as species belong to the moral sphere have seldom been taken into account in a more thorough way, although it is advocated by several important environmental ethicists. The main purpose of this article is to analyze in more detail than often has been done what the practical consequences of this ethical position would be for the use of genetic engineering on animals and plants. The practical consequences of the holistic standpoint (focused on collective entities) of Holmes Rolston, III, is compared with the practical consequences of the individualistic standpoints (focused on individual living beings) of Bernard E. Rollin and Philipp Balzer, Klaus Peter Rippe, and Peter Schaber, respectively. The article also discusses whether the claim that species are morally considerable is tenable as a foundation for policy decisions on genetic engineering.  相似文献   
87.
在概述国内土壤环境质量标准存在的问题的基础上,分析了国外土壤环境质量标准/指导值发展趋势,提出了我国土壤环境质量的三级标准体系,即:背景值标准、筛选值标准、有效态污染临界值标准,并据三级标准体系和各重金属的单项污染指数,把土壤环境质量分为七个等级:清洁、轻度玷污、中度玷污、重度玷污、轻度污染、中度污染、重度污染,用七种警示色来表示不同的污染程度,为我国土壤环境质量标准的修订提供借鉴.  相似文献   
88.
南岳珍稀濒危植物的调查研究   总被引:6,自引:0,他引:6  
在南岳野生植物中,珍稀濒危植物主要是指国家级保护植物,共有13种,其中一级2种,二级11种,它们是金钱松Pseudolarix amabilis (Nelson) Rehd.,篦子三尖杉Cephalotaxus oliveri Mast.,南方红豆杉Taxus chinensis (Pilger) Rehd.var.mairei (Lemeé et Lévl.) Cheng et L.K.Fu,榉树Zelkova Schneideriana Hand.-Mazz.,樟树Cinnamomum camphora (L.) Presl,闽楠Phoebe bournei (Hemsl.) Yang,伯乐树Bretschneidera sinensis Hemsl,绒毛皂荚Gleditsia.japonica Miq.var. velutina L.C.Li,野大豆Glycine soja Sieb. et Zucc.,花榈木Ormosia henryi Prain,毛红椿Toona sinensis (A.Juss.) Roem.var.pubescens (Franch.) Hand.-Mazz.,喜树Camptotheca acuminata Decne.,以及香果树等,本文主要介绍他们的分类位置、形态特征和地理分布状况,分析了它们的区系特征,提出应该尽快建立南岳国家级野生保护植物的核心或者优先保护地段、建立珍稀濒危植物的地理信息系统、研究其生物学和生态学特性以及采取就地或迁地保护措施来保存等对策.  相似文献   
89.
"3S"技术在生态环境动态监测中的应用研究   总被引:17,自引:0,他引:17  
针对传统生态环境动态监测方法的不足,论述了"3S"技术的特点与优势,并结合"四川省岷江中上游生态环境遥感综合调查与评价"项目,介绍了应用"3S"技术进行生态环境动态监测的方法和流程.  相似文献   
90.
万先进 《四川环境》1993,12(3):40-42
本文阐述了省级环境监测中心站在整个国家环境监测网络中的重要地位和作用。回顾了我省环境监测中心站这些年来的工作,当前存在的困难和问题,以及如何对我省环境监测中心站进行体制改革的思考。  相似文献   
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