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   534篇
  免费   52篇
  国内免费   104篇
安全科学   244篇
废物处理   13篇
环保管理   42篇
综合类   213篇
基础理论   83篇
污染及防治   66篇
评价与监测   13篇
社会与环境   3篇
灾害及防治   13篇
  2023年   6篇
  2022年   11篇
  2021年   25篇
  2020年   34篇
  2019年   20篇
  2018年   11篇
  2017年   13篇
  2016年   15篇
  2015年   19篇
  2014年   23篇
  2013年   30篇
  2012年   53篇
  2011年   66篇
  2010年   42篇
  2009年   54篇
  2008年   38篇
  2007年   40篇
  2006年   37篇
  2005年   33篇
  2004年   26篇
  2003年   10篇
  2002年   17篇
  2001年   16篇
  2000年   6篇
  1999年   6篇
  1998年   4篇
  1997年   4篇
  1996年   6篇
  1995年   6篇
  1994年   4篇
  1993年   5篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1989年   1篇
  1987年   1篇
  1984年   1篇
  1981年   1篇
  1973年   1篇
排序方式: 共有690条查询结果,搜索用时 15 毫秒
581.
家蚕——新的内分泌干扰物筛选靶标   总被引:1,自引:0,他引:1  
内分泌干扰物对人类及环境的影响日益严重,如何建立快速有效的筛选方法,从复杂的周围环境中鉴别出具有内分泌干扰活性的物质,指导人们尽量规避不必要的暴露风险,成了当前环境学家的重要任务。本文以鳞翅目昆虫的模式物种家蚕为对象,介绍了其内分泌系统组成及相关激素的作用,分析了作为内分泌干扰物筛选靶标的优势,阐述了候选的测试端点及依据,从理论和方法不同角度探讨了家蚕成为一种新的内分泌干扰物筛选靶标的可行性。  相似文献   
582.
危化品安全生产科技研究现状的文献计量分析   总被引:1,自引:0,他引:1  
为了解我国危化品安全生产科技研究现状,揭示危化品安全生产科技的动态演化过程,以中国知网文献数据为来源,采用文献计量法对2006—2014年的危化品安全生产科技相关文献进行挖掘、整理、分析。通过对比2006—2011与2012—2014年2个时间段关键词词频排序,共词聚类2012—2014年的高频关键词,分析我国危化品安全生产科技的主题结构及研究热点变化情况。研究表明:危化品、天然气管道、化工园区等关键词相关的安全生产科技,其关注度依旧较高,但针对这些传统领域的科技研发呈现出新的特点,围绕动态分级、生命周期、云计算等关键词开展的科技研究逐渐成为关注热点和优势方向;2012—2014年我国危化品安全生产科技可以归纳为6个主要研究领域。  相似文献   
583.
一种基于层次分析法的危险化学品源安全评价综合模型   总被引:6,自引:0,他引:6  
危险化学品源的安全评价是安全生产管理中的一项重要内容.目前用于危险化学品源安全评价与分级的常用方法有后果分析法、道指数法、蒙德指数法以及使用临界系数判别重大危险源的方法等.在实际应用中,单独使用某一方法时,由于存在各种片面性问题而得不到满意的评价结果; 几种方法同时使用时,其评价指标、评价结果以及结果的形式又会互相冲突.为解决上述问题,建立了基于层次分析法的综合评价模型.首先,根据安全评价要求构建3层次的评价体系,在各层次中构造判断矩阵,并计算4种常用方法相对综合评价模型的置信度; 其次,对各方法统一危险分级标准,均采用危险分数划定危险级别,并取各危险分数的加权平均值--综合危险分数作为综合评价模型下的危险源分级标准.采用综合评价模型可消除单一方法进行评价时的片面性和偏差,同时,评价结果的一致化使得判断危险化学品源的危险级别以及由此采取相应级别的管理措施成为可能,将更有利于实际安全生产管理指导.  相似文献   
584.
介绍了ASME B31.8S-2001(天然气管道完整性管理)中采用的危险区域预测模型,该模型由火灾模型、气体释放速率模型和热强度阈值3部分组成,它表明了高压天然气管道断裂后,危险区域与管线直径、运行压力的关系.  相似文献   
585.
The changes promoted by treatment of a highly polluted soil with sulphuric acid or calcium hydroxide for changing its pH value are studied by controlling physical properties (particle size, TGA and DTA curves), evolution of metal species (exchangeable, as carbonates, related to Fe‐Mn oxides, linked to organic matter and residual) and metal uptake by plant cultures. Metal contents were determined, after wet digestion with HF—HNO3—HC1O4 when necessary, by AAS (Ca, Mg, Cu, Pb, Mn, Fe, Zn) or emission (Na, K). The treatment of soil with successive amounts of sulphuric leads to changes in particle size, hydration properties and exothermic peak for organic matter combustion. Very small changes were, however, detected in the alkaline treatment of soil. Soil treatments do not have practical influence on speciation of some metals (Na, K, Mg, Pb, Mn, Fe), but the intensity of the acid treatment leads to both an increase in the Cu extraction and a decrease in the Ca solubilization, probably through gypsum formation. In the case of zinc a maximum solubility in the middle of the range of acid treatment was observed. The comparison among extractants shows solubilities high for two pollutants (Pb, Cu), associated mainly to Fe—Mn oxides and organic matter, and low for two macrocomponents (Fe, K). The rest of metals, basically present in soil as carbonates or oxides, have intermediate extractions. Pot cultures weights depended mainly on both the treatment of soil (poor development in the more acid sample and drainage difficulties in the rest of acid treatments) and the situation (very low weights in laboratory runs as compared with outside), but the irrigation with water or a diluted sulphuric acid solution (at pH = 4.0) did not produce significant weight changes. Tendencies to increase plant pollution were observed for smaller soil pH, acid irrigation and probably for outside cultures, due to uptake by leaves.  相似文献   
586.
A multiresidue analytical method was developed for the determination of 9 endocrine disrupting chemicals (EDCs) and 19 pharmaceuticals and personal care products (PPCPs) including acidic and neutral pharmaceuticals in water and soil samples using rapid resolution liquid chromatography-tandem mass spectrometry (RRLC-MS/MS). Solid phase extraction (SPE), and ultrasonic extraction combined with silica gel purification were applied as pretreatment methods for water and soil samples, respectively. The extracts of the EDCs and PPCPs in water and soil samples were then analyzed by RRLC-MS/MS in electrospray ionization (ESI) mode in three independent runs. The chromatographic mobile phases consisted of Milli-Q water and acetonitrile for EDCs and neutral pharmaceuticals, and Milli-Q water containing 0.01 % acetic acid (v/v) and acetonitrile: methanol (1:1, v/v) for acidic pharmaceuticals at a flow rate of 0.3 mL/min. Most of the target compounds exhibited signal suppression due to matrix effects. Measures taken to reduce matrix effects included use of isotope-labeled internal standards, and application of matrix-match calibration curves in the RRLC-MS/MS analyses. The limits of quantitation ranged between 0.15 and 14.08 ng/L for water samples and between 0.06 and 10.64 ng/g for solid samples. The recoveries for the target analytes ranged from 62 to 208 % in water samples and 43 to 177 % in solid samples, with majority of the target compounds having recoveries ranging between 70–120 %. Precision, expressed as the relative standard deviation (RSD), was obtained less than 7.6 and 20.5 % for repeatability and reproducibility, respectively. The established method was successfully applied to the water and soil samples from four irrigated plots in Guangzhou. Six compounds namely bisphenol-A, 4-nonylphenol, triclosan, triclocarban, salicylic acid and clofibric acid were detected in the soils.  相似文献   
587.
合成有机化学品的超临界水氧化   总被引:8,自引:0,他引:8  
研究了超临界水氧化系统中合成有机化学品 ,如酚、间苯三酚、对叔丁基酚、间甲酚、3 ,5-二甲酚、苯胺、硝基苯、叔丁醇、三氯乙醛等的氧化作用。在实验条件下 ,上述化学品均能显著降解。酚和苯胺的去除随氧化剂过氧化氢加入量增加而增加。较优的K值 (实验中加入的H2 O2 量与按反应方程化学计量的量的比值 )对酚和苯胺分别为 1 .5和 1 .1。实验结果显示 ,当系统的压力为 3 0MPa ,温度为 4 50℃ ,停留时间为 1 90s,K =2 .0 (对酚 )和系统压力为 2 5MPa,温度为 50 0℃ ,停留时间为 3 0s,K =1 .2 (对苯胺 ) ,氧化效率都接近 1 0 0 %。含酚废水处理结果表明温度、压力、停留时间 3种因素中 ,温度是主要影响因素  相似文献   
588.
Background, aim, and scope  Food consumption is an important route of human exposure to endocrine-disrupting chemicals. So far, this has been demonstrated by exposure modeling or analytical identification of single substances in foodstuff (e.g., phthalates) and human body fluids (e.g., urine and blood). Since the research in this field is focused on few chemicals (and thus missing mixture effects), the overall contamination of edibles with xenohormones is largely unknown. The aim of this study was to assess the integrated estrogenic burden of bottled mineral water as model foodstuff and to characterize the potential sources of the estrogenic contamination. Materials, methods, and results  In the present study, we analyzed commercially available mineral water in an in vitro system with the human estrogen receptor alpha and detected estrogenic contamination in 60% of all samples with a maximum activity equivalent to 75.2 ng/l of the natural sex hormone 17β-estradiol. Furthermore, breeding of the molluskan model Potamopyrgus antipodarum in water bottles made of glass and plastic [polyethylene terephthalate (PET)] resulted in an increased reproductive output of snails cultured in PET bottles. This provides first evidence that substances leaching from plastic food packaging materials act as functional estrogens in vivo. Discussion and conclusions  Our results demonstrate a widespread contamination of mineral water with xenoestrogens that partly originates from compounds leaching from the plastic packaging material. These substances possess potent estrogenic activity in vivo in a molluskan sentinel. Overall, the results indicate that a broader range of foodstuff may be contaminated with endocrine disruptors when packed in plastics.  相似文献   
589.
Tens of thousands of chemicals are currently marketed worldwide, but only a small number of these compounds has been measured in effluents or the environment to date. The need for screening methodologies to select candidates for environmental monitoring is therefore significant. To meet this need, the Swedish Chemicals Agency developed the Exposure Index (EI), a model for ranking emissions to a number of environmental matrices based on chemical quantity used and use pattern. Here we evaluate the EI. Data on measured concentrations of organic chemicals in sewage treatment plants, one of the recipients considered in the EI model, were compiled from the literature, and the correlation between predicted emission levels and observed concentrations was assessed by linear regression analysis. The adequacy of the parameters employed in the EI was further explored by calibration of the model to measured concentrations. The EI was found to be of limited use for ranking contaminant levels in STPs; the r2 values for the regressions between predicted and observed values ranged from 0.02 (= 0.243) to 0.14 (= 0.007) depending on the dataset. The calibrated version of the model produced only slightly better predictions although it was fitted to the experimental data. However, the model is a valuable first step in developing a high throughput screening tool for organic contaminants, and there is potential for improving the EI algorithm.  相似文献   
590.
黄璐  陈武  陈泉源 《环境工程学报》2010,4(12):2694-2698
通过对江汉油田采油废水水质分析以及混凝实验研究,分析采油作业返排液中主要化学组分对含油废水混凝处理效果的影响,探讨了混凝剂、常用油田化学品与浊度及油含量去除率的关系,初步分析了它们的作用机理。研究表明,在钻井液中,单宁、磺化酚醛树脂(SMP)等对含油废水处理的影响很大,在压裂液中瓜胶、重铬酸钾等的影响较大,酸化液中乙酸和柠檬酸等的影响较大,射孔液中盐酸等的影响较大。本研究的结果对于消除返排液对油田生产的不良影响,保证系列增储上产措施的实施及其有效性,避免环境污染,具有十分重要的参考价值。  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