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   1141篇
  免费   57篇
  国内免费   123篇
安全科学   207篇
废物处理   30篇
环保管理   122篇
综合类   455篇
基础理论   154篇
污染及防治   180篇
评价与监测   107篇
社会与环境   46篇
灾害及防治   20篇
  2024年   9篇
  2023年   32篇
  2022年   32篇
  2021年   28篇
  2020年   27篇
  2019年   19篇
  2018年   25篇
  2017年   16篇
  2016年   15篇
  2015年   23篇
  2014年   51篇
  2013年   41篇
  2012年   83篇
  2011年   90篇
  2010年   37篇
  2009年   40篇
  2008年   60篇
  2007年   99篇
  2006年   52篇
  2005年   47篇
  2004年   59篇
  2003年   41篇
  2002年   38篇
  2001年   38篇
  2000年   42篇
  1999年   28篇
  1998年   23篇
  1997年   28篇
  1996年   21篇
  1995年   34篇
  1994年   22篇
  1993年   13篇
  1992年   18篇
  1991年   14篇
  1990年   11篇
  1989年   10篇
  1988年   7篇
  1987年   7篇
  1986年   8篇
  1985年   6篇
  1984年   4篇
  1983年   7篇
  1982年   7篇
  1981年   7篇
  1980年   2篇
排序方式: 共有1321条查询结果,搜索用时 574 毫秒
931.
一次事故使他变成了植物人,至今,他仍躺在医院里,妻子和女儿的深情呼唤始终未能把他唤醒.  相似文献   
932.
The effect of cadmium on C and N mineralization in sewage sludge amended and unamended sandy loam, loam and clay loam soils was studied during 2 months incubation at 30+/-1 degrees C. The sludge amendment caused 15-39% increase in microbial respiration, with the maximum C mineralization in sandy loam and the minimum in loam soil. The addition of 10 microg Cd g(-1) soil had no remarkable effect on C and N mineralization and microbial biomass; whereas significant decreases in the above parameters were observed at 25 and 50 microg Cd g(-1) soil, irrespective of the sludge addition. Less NO3(-)-N accumulated at higher Cd concentration. Cd recovery was high in sandy loam and low in clay loam soil. DTPA extractable Cd exhibited a significant negative correlation with microbial biomass (r=-0.58* to -0.86*; p < 0.05).  相似文献   
933.
采用美国EPA规定的水中优先控制污染物的水体有机物浓度标准,计算滇池罗家营水域中污染物的健康风险,并参考美国EPA对致癌风险和非致癌风险的相关定义,对这些化合物的环境健康风险进行了评价。结果表明:2007年滇池罗家营水域污染物非致癌及致癌健康风险值均低于美国EPA给出的参考标准,表明该水域水总污染物不会对人体健康产生风险。  相似文献   
934.
依据HSE管理体系标准,结合有关安全工程理论和风险管理理论与方法,提出了HSE风险管理的思想模式,对其含义和指导意义进行了说明。  相似文献   
935.
PROBLEM: Hundreds of laws have been implemented in the United States over the past few decades designed to reduce alcohol-impaired driving and the crashes that often result. One approach has been to lower the legally allowable alcohol concentration for drivers. We examined the effects of changes in legal BAC limit in 28 U.S. states from January, 1976 to December, 2002. METHOD: An interrupted time-series quasi-experimental design was used, incorporating non-alcohol-related crashes as comparisons. Four outcome measures of alcohol-related crash involvement were examined: single-vehicle nighttime, BAC=0.01-0.07, BAC=0.08-0.14, and BAC>/=0.15. Missing BAC test result data were handled by using multiple imputations. Analyses involved estimation of state-specific ARIMA models, controlling for other factors affecting overall crash rates and other major DUI policy changes. Inverse variance weighting methods were used to pool results across states for the most precise underlying estimate of effect of legal BAC limits. RESULTS: Considerable state by state variability in estimated effects was observed, but results from the pooled analyses were clear and consistent. Changes in legal BAC limits significantly affected alcohol-related fatal crash involvement for both the SVN and BAC test result measures, and the laws affected drivers at all drinking levels. SUMMARY: An estimated 360 deaths are prevented each year in the United States as a result of the move from a 0.10 to 0.08 legal limit in recent years, and an additional 538 lives could be saved each year if the United States reduced the limit to 0.05, consistent with limits in most countries worldwide. IMPACT ON INDUSTRY: Given the significant effects of lower legal BAC limits on fatal crash involvement, businesses should support implementation of laws that further reduce the legal BAC limit for all drivers. Furthermore, all companies should set higher standards for employees, such as a zero allowable BAC limit for driving during work time.  相似文献   
936.
水电站综合自动化系统抗电磁干扰措施   总被引:1,自引:0,他引:1  
金长德  郑锡恩 《安全》2007,28(12):7-10
综合自动化系统及其装置在水电站分布广泛,它们大都处于各种电磁环境中,很容易受到电磁骚扰而不能正常工作,给水电站安全经济运行带来重要影响.为了保证水电站综合自动化系统能正常工作并具有高度可靠性,必须采取各种有效的抗电磁干扰的措施,增强系统的抗干扰性能.  相似文献   
937.
BACKGROUND: Methods to study driving patterns and exposure of older drivers have typically relied on surveys or driving diaries. Electronic data logging devices may offer a reliable, alternative method of measuring driving exposure, and global positioning system (GPS) technology may be able to provide further information about driving patterns. OBJECTIVES: The aim of this study was to compare a driving diary with two electronic data logging devices, one of which had GPS capability, in order to identify which method best assesses the driving exposure and habits of older drivers as well as the method most acceptable to study participants. METHOD: In this prospective cohort study we recruited 20 participants aged 70 years or more (mean 78; range 70-85) (15 men and 5 women). The participants' driving patterns were recorded for one week with an electronic data logging device with GPS (FleetPulse), followed by recording for a further week with an electronic data logging device without GPS (CarChip). During both time periods the subjects also completed a standard driving diary. RESULTS: More comprehensive information, including braking and acceleration patterns, duration of driving time, time of day, and maximum speeds, was collected with the electronic devices than with the driving diary. There was excellent correlation between the driving diary data and those obtained with the CarChip (r = 0.9; p < 0.01). The correlation between the driving diary data and the FleetPulse data was moderate (r = 0.56; p = 0.02). The subjects clearly preferred the electronic monitoring devices over the driving diary. GPS data were able to demonstrate driving routes. CONCLUSIONS: Electronic data logging devices are a valid method for recording the driving patterns of older adults. These devices also reduce burden and improve the completeness of data.  相似文献   
938.
A partial life-cycle test with the model fish Danio rerio was performed in order to evaluate the genotoxic potential of binary mixtures of xenoandrogenic (tributyltin--TBT; triphenyltin--TPT) and an estrogenic compound (ethinylestradiol--EE2). Five days post-fertilisation larvae were diet-exposed to environmental relevant concentrations of TBT and TPT (25 ng/g-100 ng/g), and water-exposed to ethinylestradiol (3.5 ng/L) for a four-month period; binary mixtures of TBT plus EE2 and TPT plus EE2 were run in parallel. The erythrocytic nuclear abnormalities (ENA) assay in circulating erythrocytes was used to evaluate genotoxicity in the end of the four-month exposure period. A significant increase (p<0.05, Kruskall-Wallis non-parametric ANOVA) in ENA frequency, in comparison with control animals, was observed in those animals exposed to TBT and TPT (the highest doses only), and to EE2 and the binary mixtures, although neither synergistic nor additive effects of the tested compounds were evident. Overall, the results clearly indicate that chronic exposure to low levels of TBT, TPT, EE2 and binary mixtures of TBT plus EE2 and TPT plus EE2 are genotoxic to zebrafish, which may suggest that wild fish populations may be under increased DNA damage in areas contaminated by these endocrine disrupting chemicals.  相似文献   
939.
大气中多环芳烃气/粒分配的不确定性分析   总被引:2,自引:2,他引:0  
于2010年8月10~14日用双层石英膜和双层聚氨酯泡沫(PUF)的方法采集并分析了厦门大学海洋楼顶大气中气态和颗粒态多环芳烃(PAHs),并采用标准误差传递方法对气/粒分配系数(Kp)的不确定度进行了分析.测量结果显示,低分子量PAHs如萘、 苊、 二氢苊和芴在PUF吸附体系中的穿透能力最强,穿透率接近50%;如考虑第一层石英滤膜对气态萘、 苊和二氢苊的吸附影响,则校正后的Kp值比校正前相应的Kp值低1个数量级以上.采用标准误差传递方法得到PAHs气/粒分配系数Kp的不确定度,介于28.14%~50.37%之间,且表现为易挥发和难挥发性PAHs的Kp值皆具有较高的不确定度,而半挥发性PAHs的Kp值的不确定度则较小.Kp值的不确定度来源分析显示,气态PAHs浓度的不确定度的影响最大(方差贡献均值=77.9%),其次为颗粒态PAHs浓度的不确定度(方差贡献均值=22.0%),大气颗粒物浓度的不确定度影响最小(方差贡献均值=0.1%).因此,选择合适的采样系统以获取更加准确的气态PAHs的浓度,是提高PAHs气/粒分配系数准确度的关键.  相似文献   
940.
分析了国内外制药行业清洁生产发展现状,阐明了我国制药行业实施清洁生产的必要性,重点分析清洁生产推行过程中存在的问题、产生原因及应采取的对策。  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