首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2456篇
  免费   53篇
  国内免费   46篇
安全科学   1267篇
废物处理   19篇
环保管理   192篇
综合类   735篇
基础理论   68篇
环境理论   1篇
污染及防治   60篇
评价与监测   93篇
社会与环境   38篇
灾害及防治   82篇
  2024年   1篇
  2023年   23篇
  2022年   15篇
  2021年   74篇
  2020年   83篇
  2019年   35篇
  2018年   15篇
  2017年   35篇
  2016年   67篇
  2015年   69篇
  2014年   101篇
  2013年   89篇
  2012年   103篇
  2011年   115篇
  2010年   64篇
  2009年   88篇
  2008年   76篇
  2007年   80篇
  2006年   78篇
  2005年   139篇
  2004年   174篇
  2003年   141篇
  2002年   93篇
  2001年   70篇
  2000年   107篇
  1999年   108篇
  1998年   111篇
  1997年   66篇
  1996年   68篇
  1995年   99篇
  1994年   40篇
  1993年   37篇
  1992年   32篇
  1991年   20篇
  1990年   10篇
  1989年   5篇
  1988年   3篇
  1987年   4篇
  1986年   2篇
  1985年   4篇
  1984年   1篇
  1983年   1篇
  1979年   2篇
  1978年   2篇
  1977年   3篇
  1970年   1篇
  1967年   1篇
排序方式: 共有2555条查询结果,搜索用时 31 毫秒
951.
A battery of biomarkers has recently been developed in the earthworm Eisenia andrei. In this study, different biomarkers (i.e. Ca2+-ATPase activity, lysosomal membrane stability-LMS, lysosomal lipofuscin and neutral lipid content) were utilized to evaluate the alterations in the physiological status of animals, induced by exposure for 3 d to different sublethal concentrations of TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) (1.5 × 10−3, 1.5 × 10−2, 1.5 × 10−1 ng mL−1) utilizing the paper contact toxicity test. Lysosome/cytoplasm volume ratio and DNA damage were also evaluated as a biomarker at the tissue level and as a biomarker of genotoxicity, respectively. Moreover, the NR retention time assay conditions were optimized for the determination of in vivo LMS in earthworm coelomocytes. The results demonstrate that LMS and Ca2+-ATPase activity were early warning biomarkers able to detect the effects of minimal amounts of TCDD and that biomarkers evaluated at the tissue level are important for following the evolution of the stress syndrome in earthworms. To evaluate the health status of the animals, an Earthworm Expert System (EES) for biomarker data integration and interpretation was developed. The EES proved to be a suitable tool able to rank, objectively, the different levels of the stress syndrome in E. andrei induced by the different concentrations of TCDD.  相似文献   
952.
Sewage sludge amendment on agricultural soils has recently become a practice of heightened interest, as a consequence of sewage sludge production increase. This practice has benefits to soil and crops, however it may also lead to environmental contamination, depending on the characteristics of the fields. In order to define the suitability of the different agricultural fields to receive sewage sludge, a spatial tool is proposed. This tool, elaborated in GIS platform, aggregates different criteria regarding human exposure and environmental contamination.The spatial tool was applied to a case study in the region of Catalonia (NE of Spain). Within the case study, each step of the tool development is detailed. The results show that the studied region has different suitability degrees, being the appropriate areas sufficient for receiving the total amount of sewage sludge produced. The sensitivity analysis showed that “groundwater contamination”, “distance to urban areas”, “metals concentration in soil” and “crop type” are the most important criteria of the evaluation.The developed tool successfully tackled the problem, providing a comprehensive procedure to evaluate agricultural land suitability to receive sewage sludge as an organic fertilizer. Also, the tool implementation gives insights to decision makers, guiding them to more confident decisions, based on an extensive group of criteria.  相似文献   
953.
Often perceived as a Cinderella material, there is growing appreciation for solid waste as a renewable content thermal process feed. Nonetheless, research on solid waste gasification and sulphur mechanisms in particular is lacking. This paper presents results from two related experiments on a novel two stage gasification process, at demonstration scale, using a sulphur-enriched wood pellet feed.Notable SO2 and relatively low COS levels (before gas cleaning) were interesting features of the trials, and not normally expected under reducing gasification conditions. Analysis suggests that localised oxygen rich regions within the fluid bed played a role in SO2’s generation. The response of COS to sulphur in the feed was quite prompt, whereas SO2 was more delayed. It is proposed that the bed material sequestered sulphur from the feed, later aiding SO2 generation. The more reducing gas phase regions above the bed would have facilitated COS – hence its faster response. These results provide a useful insight, with further analysis on a suite of performed experiments underway, along with thermodynamic modelling.  相似文献   
954.
A workshop was held in Berlin September 12–14th 2012 to assess the state of the science of the data supporting low dose effects and non-monotonic dose responses (“low dose hypothesis”) for chemicals with endocrine activity (endocrine disrupting chemicals or EDCs). This workshop consisted of lectures to present the current state of the science of EDC action and also the risk assessment process. These lectures were followed by breakout sessions to integrate scientists from various backgrounds to discuss in an open and unbiased manner the data supporting the “low dose hypothesis”. While no consensus was reached the robust discussions were helpful to inform both basic scientists and risk assessors on all the issues. There were a number of important ideas developed to help continue the discussion and improve communication over the next few years.  相似文献   
955.
通过对汽车修理养护企业喷烤漆废气排放现状进行调查分析,指出中国目前适用于控制汽车修理养护企业废气排放的标准《大气污染物综合排放标准》(GB 16297-1996)在实际运用中存在的问题。依据《制定地方大气污染物排放标准的技术方法》(GB/T 3840-1991)《大气污染物综合排放标准详解》《工作场所有害因素职业接触限值化学有害因素》(GBZ 2.1-2007)《工业企业设计卫生标准》(TJ 36-1979)、美国环保局多介质环境模型等,用不同方法计算汽车修理养护企业排放的废气中几种挥发性有机物的排放浓度和排放速率限值,并对监测结果进行评价分析,提出编制汽车修理养护企业废气排放控制标准的建议。  相似文献   
956.
浅谈强化环境监测质量管理体系建设   总被引:19,自引:0,他引:19  
针对新的历史条件下环境监测质量管理体系建设不断完善的实际需求,提出了完善监测技术体系、补充建立量值溯源基准体系、建立监测质量控制指标体系、提高环境监测人员技术能力和水平、有效运行环境监测质量体系、建立健全监测质量监督机制等6项提升环境监测质量管理水平的体系建设思路。  相似文献   
957.
山西省重点污染源自动监控系统是集环境监测、监视和控制于一体的污染源自动监控系统,解决了传统污染源监控系统"只监不控"、"只监结果不监过程"的问题。介绍了该系统的组成、功能及技术特点,并于2010年3月通过该系统对超标排放企业远程监控的实施情况进行了分析。结果表明,该系统能够有效对监控企业进行实时监测,并对污染超标企业进行远程控制和警示,从而有效提高了环境监管水平和执法效率,加强了防止和应对突发性重大环境污染事故的能力。  相似文献   
958.
通过对7种废气自动监测系统的比较研究和现场测试,提出了非分散红外法、紫外差分法、紫外荧光法、化学发光法等多种SO2和NO x自动监测技术在低浓度范围实现准确定量监测的性能评价方法,定义了CEMS的系统检出限及其主要影响因素。建议采用系统检出限、线性误差等关键参数作为低浓度CEMS的性能评价方法,提出将全系统多点标准气体校准或加标回收率作为验收和质控监督的基本方法。  相似文献   
959.
界定机动车维修、报废过程中产生的固体废物、废水、土壤污染为机动车二次污染,并通过实地调查、监测分析广州市12家定点报废汽车回收公司,开展机动车二次污染现状研究。研究表明,报废机动车回收过程中对资源化金属的回收利用成效较好,但对用途不大的部件随意渠道转移,对危险废物和严控废物未能较好处理;大多没有完善废水处理设施,废水直接排放;土壤多项特征污染物超标严重。针对广州市机动车二次污染现状,提出了加强法规建设、环境监控、行业管理、清洁生产等防治措施。  相似文献   
960.
采用A—O1-O2生物膜系统处理模拟废水,通过动力学分析与推导,并根据实验数据求取相关的动力学参数,最后得出A、O1、O2单段以及系统整体对于CODCr,和NH4+-N降解的动力学模型,一方面为了便于从理论上分析去除CODCr、NH4+-N的规律,另一方面为该系统的实际工程设计和应用提供理论依据。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号