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51.
简要介绍了可靠性强化试验技术原理与特点,总结了其在平板电视电源模块研发阶段中的应用方法,着重阐述了试验过程和五个类型的试验剖面;引述了激发应力范围的统计学方法,并给出了部分产品应用实施可靠性强化试验技术的典型案例,说明其在激发暴露产品设计、工艺缺陷等方面的突出效果。  相似文献   
52.
菹草的经济价值及其栽培与养鱼技术   总被引:12,自引:0,他引:12  
菹草是渔业水域生态系统中的初级生产者,为渔业生产的重要自然资源之一、根据近年来的试验研究成果,本文探讨了菹草的自明、药用、饲用价值及其在渔业水域中对自然国类资原的增殖与保护作用,介绍了菹草人工栽培与养鱼的技术措施。  相似文献   
53.
/ Limit values are legal limits for the concentrations of substances in the environment. They must be agreed upon in a consensual procedure between science, economics/technology, and political forces. This is a crucial political precondition for their social acceptance. The arguments put forward to justify their expediency and numerical level are based not only on risk-benefit considerations but also on the aspect of the technical avoidability of direct and indirect exposure. The critical assessment of the direct benefit of specified exposures falls within the responsibility of economics/technology, whereas criteria for their potential adverse effects (direct and indirect) are provided by medicine/biochemistry and/or ecology. Within this concept, the avoidance of nonbeneficial-even if not openly adverse-exposure is the essential aim of environmental hygiene and should be promoted by politics/science. In general, society or segments thereof reject adverse, accept beneficial, and tolerate unavoidable exposure. Conflicts of interest arise when different groups of society simultaneously define a given exposure as being adverse, beneficial, and unavoidable. Therefore, from the viewpoint of society as a whole, an optimal exposure lies as far as reasonably achievable at a level lower than known or plausible adverse effect thresholds (as defined by toxicology or ecology). This optimal level of exposure must be determined using a transparent and, hence, public procedure.KEY WORDS: Legal limit values; Benefit threshold; Social acceptance; Social tolerability; Adverse effect threshold; Avoidable exposure; Tolerance threshold; Environmental hygiene  相似文献   
54.
ABSTRACT: A common problem arises in testing for trends in water quality when observations are reported as “less than detection limit.” If a single detection limit is used for the entire study, existing non-parametric statistical methods, modified for ties, are applicable. If, however, the detection limit varies during the course of the study, resulting in multiple detection limits, then the commonly used trend detection methods are not appropriate. A statistic similar to Kendall's tau, but based on expected ranks, is proposed. Monte Carlo simulations show that the normal approximation to the distribution of this statistic is quite good, even for small samples and a large proportion of censored observations. The statistic is also shown to have greater power than the ad-hoc method of treating all observations less than the target censored observation as tied.  相似文献   
55.
Three different sizes of hog farms were selected to analyze the carbon emissions reduction and the cost–benefit of three methane digester systems. The sizes of the digesters are 2,200, 2,200 and 800 m3, respectively. The sales of slaughter hogs from them are 50,000, 35,000 and 10,000 head, respectively. The carbon emissions reductions were 5,237, 4,017, and 1,334 tons, respectively. The results show that while the methane digester systems have a significant effect on carbon emissions reduction, it is difficult to operate the systems sustainably. If the carbon emissions reduction can be traded at high enough prices in the carbon offset markets, then the systems will be profitable and sustainable. Newly established China's domestic carbon offset market could provide this possibility, but more government support is needed. In addition, this study shows that scale economies make the digester adoption relatively more profitable for larger farms than smaller ones.  相似文献   
56.
水资源多目标协同配置:全价值基础上的框架研究   总被引:1,自引:1,他引:1       下载免费PDF全文
从资源的视角而言,水资源具有的社会、经济、生态属性中,社会属性和生态属性所提供的生态功能和服务多是外部性和非市场的,其价值在纯粹的市场驱动下难以充分实现。从资源管理视角而言,水资源多目标协同配置的实质是水资源多重属性功能和服务的均衡。因此,将具有外部性的社会、生态功能和服务与具有经济价值的功能和服务同时纳入配置框架,是实现多目标协同配置实践的关键问题。本文在回顾水资源配置和水资源非市场价值评估的相关研究的基础上,围绕我国现行水资源配置存在的主要问题,通过水资源的全价值(市场价值和非市场价值)将其多属性功能和公众意愿纳入水资源多目标协同配置中,从水资源管理信息系统、全价值评估和配置管理的绩效评价三个方面构建了水资源配置的多目标协同框架,最后提出相关的保障政策建议。  相似文献   
57.
以非遗研学旅行产品为例,需求侧在产品开发中的缺位是造成产品问题的重要原因,可运用价值共创理论指导产品开发。根据调查问卷结果及分析,基于对实际决策人--学生家长的产品选择偏好、考虑因素、价值感知、购买意向与满意度4个维度的分析,提出优化非遗研学产品开发的4个方面建议:政府营造研学氛围,加强制度保障;学校开展非遗教育,发挥桥梁作用;供方考虑市场需求,强化产品内涵;供需两侧共建价值共创平台。  相似文献   
58.
The process of producing cement products from solid waste can increase the level of pollutants in the cement products. Therefore, it is very important to establish a pollution control standard for cement products to protect the environment and human health. This paper presents acceptance limits for the availability of heavy metals in cement products which have been produced from solid wastes and explains how the limits have been calculated. The approach and method used to formulate these criteria were based on EN 12920. The typical exposure scenarios used in this paper involve concrete being used for drinking water supply pipelines and concrete pavements and are based on an analysis of typical applications of cement in China, and the potential for contact with water. The parameters of a tank test which was based on NEN 7375 were set in accordance with the environmental conditions of typical scenarios in China. Mechanisms controlling the release of heavy metals in concrete and a model for that release were obtained using the leaching test. Finally, based on acceptance criteria for drinking water and groundwater quality in China, limit values for the availability of heavy metals in concrete were calculated.  相似文献   
59.
当前学术界对于GEP的概念内涵和核算方法仍在探索之中,而地方实践已然走在理论研究之前。GEP核算是生态服务价值的货币化评价,主要是为了科学认识生态系统服务的潜在价值,不等同于生态服务价值的市场显现;核算的出发点是为了更好保护自然资本,而非生态产品价值转化。GEP核算通过货币化评价生态服务价值,将自然资本保护更好地纳入经济社会发展决策,为完善生态补偿机制、进行生态文明绩效考核、引导人造资本和人力资本进入生态产业化提供重要参考依据。GEP和GDP都是流量,将GEP直接转化为GDP在逻辑上不成立。如何使GEP核算更好地服务于生态产品价值实现,需要在理论上厘清逻辑关联,在实践中明晰政策边界。  相似文献   
60.
降低消费阶段的碳排放量对实现国家“双碳”战略目标具有重要意义。在此背景下,本研究从碳标签出发,引入“亲社会行为”这一变量,提出研究假设并构建了消费者低碳购买意愿的模型,利用调查问卷和结构方程模型进行数据分析,探究碳标签对消费者低碳购买意愿的影响,并分析亲社会行为在其中的调节作用。研究结果显示,碳标签认知、碳标签宣传均直接影响消费者的低碳购买意愿,碳标签公信力对低碳购买意愿没有直接影响;感知价值和购买态度在碳标签相关因素与低碳购买意愿之间起到完全或部分中介作用;亲社会行为在感知价值和购买态度对低碳购买意愿产生中介效应的链路上具有调节作用。基于研究结果,本文从提高消费者碳标签的认知水平、增强碳标签的宣传效果、提升碳标签的公信力、倡导亲社会的低碳行为等方面提出对策建议,以期通过政府、企业和消费者的多方努力,促进消费者积极参与低碳消费,实现消费领域的低碳变革。  相似文献   
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