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   1253篇
  免费   143篇
  国内免费   574篇
安全科学   117篇
废物处理   54篇
环保管理   96篇
综合类   855篇
基础理论   422篇
污染及防治   240篇
评价与监测   126篇
社会与环境   44篇
灾害及防治   16篇
  2024年   7篇
  2023年   30篇
  2022年   48篇
  2021年   38篇
  2020年   45篇
  2019年   56篇
  2018年   58篇
  2017年   79篇
  2016年   74篇
  2015年   96篇
  2014年   83篇
  2013年   239篇
  2012年   124篇
  2011年   127篇
  2010年   76篇
  2009年   95篇
  2008年   68篇
  2007年   87篇
  2006年   91篇
  2005年   57篇
  2004年   34篇
  2003年   54篇
  2002年   54篇
  2001年   54篇
  2000年   35篇
  1999年   27篇
  1998年   27篇
  1997年   24篇
  1996年   25篇
  1995年   19篇
  1994年   10篇
  1993年   5篇
  1992年   6篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   3篇
  1987年   4篇
  1986年   3篇
  1979年   2篇
  1977年   1篇
  1973年   1篇
排序方式: 共有1970条查询结果,搜索用时 93 毫秒
861.
This article presents results from investigations of run-off frommaterials used on buildings and other constructions obtained byshort term exposures of smaller model surfaces and one year exposures of larger materials surfaces on buildings and other constructions. Elevated concentrations of metals in run-off wereobserved for a wide range of different materials used on buildings and other constructions. Sources of metal emission tothe environment includes copper (Cu) surfaces, galvanized steel,impregnated wood, lead (Pb) surfaces, asphalt surfaces, paintedmaterial stainless steel and concrete. Metal emission rates fromsurfaces of copper and galvanized steel were measured from surfaces on buildings during 12 months exposure. The magnitude of metal emission form other surfaces was also estimated and theapplicability of these data for calculations of metal flows inan urban environment is discussed.  相似文献   
862.
二氧化硫和铅联合染毒对小鼠遗传物质的损伤   总被引:1,自引:0,他引:1  
运用单细胞凝胶电泳技术研究了SO2和醋酸铅亚急性联合染毒对雄性小鼠脑、肺、脾、肾细胞DNA的损伤.结果表明,在42mg/m3 SO2和0.2%醋酸铅单独及联合作用下,小鼠脑、肺、肾、脾细胞DNA迁移距离均比对照组显著增加,而且铅可以加剧SO2对脑、肾、脾细胞核DNA的损伤程度;SO2对肺细胞核DNA的损伤程度要比铅的损伤大,小鼠肺细胞核DNA迁移距离在SO2和醋酸铅联合作用组与醋酸铅单独作用组间有极显著性差异(P<0.01),而与SO2单独作用组间没有显著性差异.SO2和醋酸铅均可引起小鼠组织细胞的DNA损伤,它们对脑、肺、脾、肾的损伤程度不同,在一定条件下存在明显的协同效应,可以增强彼此的毒性作用.这意味着SO2和铅均有引起哺乳动物细胞基因突变的潜在危险,大气SO2污染与铅的污染可能加剧某些疾病的发生与发展.  相似文献   
863.
沈阳市土壤铅对儿童血铅的影响   总被引:4,自引:1,他引:3  
研究了沈阳市土壤铅和儿童血铅的动态关系,鉴于今后土壤是儿童最重要的铅暴露源,通过土壤铅预测儿童血铅,并计算当土壤铅含量削减到土壤质量二级标准时,儿童血铅恢复到安全阈值(10μg·dL-1需要的时间,从而为土壤修复提供理论依据.研究表明,土壤铅和儿童血铅的相关系数在地理区水平上最高,为0.9200,地理区客观地代表了儿童铅暴露的真实范围.西部工业区有约90%的儿童血铅水平都高于安全阈值;东部儿童血铅水平最低,几乎没有超标现象;其它地理区儿童血铅的超标范围在3.48%~31.81%.西部工业区儿童血铅恢复到安全阈值以下所需的时间最长,平均为26.68月,其次为北部、东北部、西南部、西北部和中部,东部儿童已在安全水平.无论各地理区儿童血铅水平,还是平均恢复时间和最长恢复时间都受土壤铅含量控制.  相似文献   
864.
Abstract

One of the dominant tree species growing within and around the eastern portion of Los Alamos National Laboratory (LANL), Los Alamos, NM, lands is the pinon pine (Pinus edulis). Pinon pine is used for firewood, fence posts, and building materials and is a source of nuts for food—the seeds are consumed by a wide variety of animals and are also gathered by people in the area and eaten raw or roasted. This study investigated the (1) concentration of 3H, 137Cs, 90Sr, totU, 238Pu, 239, 240Pu, and241 Am in soils (0‐ to 12‐in. [31 cm] depth underneath the tree), pinon pine shoots (PPS), and pinon pine nuts (PPN) collected from LANL lands and regional background (BG) locations, (2) committed effective dose equivalent (CEDE) from the ingestion of nuts, and (3) soil to PPS to PPN concentration ratios (CRs). Most radionuclides, with the exception of 3H in soils, were not significantly higher (p < 0.10) in soils, PPS, and PPN collected from LANL as compared to BG locations, and concentrations of most radionuclides in PPN from LANL have decreased over time. The maximum net CEDE (the CEDE plus two sigma minus BG) at the most conservative ingestion rate (10 lb [4.5 kg]) was 0.0018 mrem (0.018 μSv); this is far below the International Commission on Radiological Protection (all pathway) permissible dose limit of 100 mrem (1000 μSv). Soil‐to‐nut CRs for most radionuclides were within the range of default values in the literature for common fruits and vegetables.  相似文献   
865.
化学品事故应急响应中危害距离的确定   总被引:2,自引:0,他引:2  
介绍了不同国家、机构确定的毒性物质、易燃易爆物质紧急暴露限值和化学品事故中危害距离的确定方法,并以液氯钢瓶泄漏事故说明毒性危害距离的确定,以天然气管线泄漏火灾、爆炸事故说明火灾爆炸事故危害距离的确定。  相似文献   
866.
The increase of fresh vegetable and fruit (FVF) intake could contribute to the prevention of obesity and several major pathologies and thus represents a major public health goal in industrial countries. Nutritional recommendations for increased consumption of FVF could lead to ingestion of unwanted amounts of pesticides. This study was undertaken to evaluate theoretical exposure of French adults to pesticide residues under increasing amounts of FVF intake. Balanced menus with 200 – 400 – 600 – 800 and 1200 g FVF/day were established. Amounts of active substances brought by every FVF vector, at the maximum residue level (MRL) were summed up to determine the intake for each active substance. Values were compared to the Acceptable Daily Intake (ADI) to point out any potential over exposure. A maximalistic approach was adopted and no reducing factor due to processing was taken into account. It was found that under minimal recommended consumption of fruit and vegetables (400 g/d), no active substance reached the ADI, but 18 vs 144 were over 10% of the ADI. Raising FVF to 600 g/d increased the number of active substances over 10 % of the ADI to 24, but again in no case was the ADI exceeded. Doubling the intake to 800 g/d gives values over the ADI for 2 active substances only (cyhexatin and thirame). It was concluded that the increase in fruit and vegetables up to 800 g per day should not expose adults over the ADIs for a majority of authorized pesticides. In this regard, residues levels of ten active substances in fruit and vegetables should deserve particular attention.  相似文献   
867.
Limit values (LVs) are legal concentration limits for constituents, residues and contaminants in consumer products or for emissions from production processes into environmental compartments. They are a traditional regulatory aid to manage chemicals in human environments. To make them proactive, LVs should become enforced by means of a transparent and informed decision process whose starting point is the Basic Rule of Environmental Hygiene, BREH:Avoid useless exposure as far as possible, minimize useful exposure in a reasonable manner, and prevent that exposure which is dangerous. The BREH calls upon minimizing exposure not only according toon site risk potentials and acceptance, but also tooff site avoidability and acceptability.  相似文献   
868.
多种污染物混合特别是低浓度下的混合对生物的联合毒性是生态毒理学研究的热点之一。选择了3类污染物苯酚、间甲基苯酚、苯胺、对硝基苯胺、硝酸铅,采用美国微板光度计测定了它们对发光菌青海弧菌.Q67(Vibrio-qinghaiensissp-Q67)的单一及联合毒性。应用非线性拟合技术模拟了这5种物质及其混合物的剂量.效应曲线,硝酸铅可用Logit模型模拟,其它4个物质能用Weibull模型准确描述,所有拟合相关系数在0.98以上,均方根误差在O.02以下。根据纯物质的EC50值,获得这5个物质的毒性强弱顺序:硝酸铅〉对硝基苯胺〉间甲基苯酚〉苯酚〉苯胺。混合实验设计了各物质在EC50、EC1、无观察效应浓度(noobserved effectcon centration,NOEC)比例的混合。用浓度加和(doseaddition,DA)和独立作用模型(independentaction,IA)对混合物毒性进行预测。IA基本准确预测了这5个物质在各自EC50混合的毒性。DA与队模型都稍微过高地预测了以EC。及NOEC浓度比例混合的联合毒性,但都在毒理学实验容许的范围之内。这5个物质以NOEC混合时对测试生物Q67没有产生明显毒性,但是还不能判定这些物质在此浓度下混合是安全的。污染物在各自的NOEC浓度下混合是否对其它生物有潜在的威胁还需更多毒理学实验支持。  相似文献   
869.
ABSTRACT

An evaluation of acute dietary exposure to pesticide residues, applying deterministic and stochastic methods, was performed for a selected group of pesticides in two representative age groups from Argentina. Thus, 28 active ingredients (a.i.) and 75 food items were evaluated for the group of 2–5-year-old children, while 9 a.i. and 59 food items were considered for the 10–49-year-old women group. A deterministic assessment was conducting following the Food and Agriculture Organization (FAO) and World Health Organization (WHO) procedure but using the national maximum residue limits (MRLs) as pesticide residue concentration data, while in the stochastic approach, a theoretical distribution modeled with the available information was used. Food consumption data were obtained from the 2004–2005 comprehensive national nutrition and health survey. The risk was estimated by comparing the short-term dietary exposure with the acute reference dose (ARfD) values for each pesticide-food combination evaluated. In the deterministic assessment, 173 (39.1%) and 40 (31.3%) combinations exceeded the ARfD thresholds for the 2–5-year-old children and 10–49-year-old women groups, respectively. This conservative study generated relevant information as a first stage of acute dietary risk assessment in Argentina.  相似文献   
870.
Use of fipronil {5-amino-1-[2,6-dichloro-4-(trifluoromethyl)phenyl]-4-trifluoromethyl)sulfinyl]-1H-pyrazole-3-carbonitrile CAS 120068–37-3} topical pet products on dogs and cats introduces low level residues into residences. Distribution and fate studies of fipronil on pets and in residences were performed to evaluate potential determinants of human exposure. Fipronil, desulfinyl fipronil, fipronil sulfone and fipronil sulfide were measured on hair clippings and brushed hair. The derivatives usually represented <10% of fipronil applied. Cotton gloves worn over impervious nitrile gloves, cotton cloths placed indoors in locations frequented by pets, and cotton socks worn by residents as direct dosimeters collected fipronil and its derivatives listed above in low amounts during 4-week study periods. Subsequent acid hydrolysis urine biomonitoring did not reveal significant excretion of biomarkers at ppb levels. The human exposure potential of fipronil is low relative to levels of health concern.  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