全文获取类型
收费全文 | 4237篇 |
免费 | 315篇 |
国内免费 | 209篇 |
专业分类
安全科学 | 439篇 |
废物处理 | 37篇 |
环保管理 | 599篇 |
综合类 | 1562篇 |
基础理论 | 269篇 |
污染及防治 | 160篇 |
评价与监测 | 1524篇 |
社会与环境 | 67篇 |
灾害及防治 | 104篇 |
出版年
2024年 | 16篇 |
2023年 | 70篇 |
2022年 | 114篇 |
2021年 | 107篇 |
2020年 | 168篇 |
2019年 | 95篇 |
2018年 | 85篇 |
2017年 | 115篇 |
2016年 | 154篇 |
2015年 | 194篇 |
2014年 | 237篇 |
2013年 | 288篇 |
2012年 | 300篇 |
2011年 | 314篇 |
2010年 | 227篇 |
2009年 | 227篇 |
2008年 | 156篇 |
2007年 | 234篇 |
2006年 | 226篇 |
2005年 | 214篇 |
2004年 | 151篇 |
2003年 | 221篇 |
2002年 | 130篇 |
2001年 | 126篇 |
2000年 | 111篇 |
1999年 | 85篇 |
1998年 | 61篇 |
1997年 | 77篇 |
1996年 | 58篇 |
1995年 | 39篇 |
1994年 | 34篇 |
1993年 | 36篇 |
1992年 | 14篇 |
1991年 | 14篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 6篇 |
1987年 | 6篇 |
1986年 | 4篇 |
1985年 | 4篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 1篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1973年 | 1篇 |
排序方式: 共有4761条查询结果,搜索用时 359 毫秒
421.
Two industrial sites were investigated based on years of available hydrogeologic information and monitoring data for soil and groundwater. Collected data were forensically evaluated using age-dating and fingerprinting methods. The previous business uses of the project sites were as a gas station, laundry/dry-cleaning service, and car wash with petroleum underground storage tanks (USTs). As a result, these sites were exposed to a number of toxic contaminants at relatively high concentrations. Source control was necessary for successful remediation and the ultimate removal of the remaining compounds from these industrial sites. Although contaminated soil around the source was excavated during the remedial action and the high concentrations of contaminants were reduced, typical groundwater contaminants such as petroleum hydrocarbons as gasoline (TPH-G), benzene, toluene, ethylbenzene, xylenes (BTEX), and oxygenates including methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA) were persistently found at the studied sites around the source points. The plume and concentration of contaminants had changed their shapes and strength for all monitoring periods. Thus, additional source control seems to be a requirement for the complete removal of source contamination, which must be ascertained with groundwater and soil monitoring on a regular time base. For the study sites, monitored natural attenuation was relatively feasible for the long-term plan; however, it did not offer a perfect remediation solution for an ultimate goal because of residual toxic compounds that might have affected the surrounding residential areas at higher concentrations than their health limits. Therefore, as a remediation strategy, the combination of clean-up technology and natural attenuation with monitoring activities are more highly recommended than either clean-up or natural attenuation used separately. 相似文献
422.
423.
424.
425.
PM2.5在线监测技术概述 总被引:4,自引:0,他引:4
针对PM2.5颗粒物监测技术和PM2.5的监测网络的建设,重点介绍了美国多年来对PM2.5的监测状况,以及采用的Beta射线法、Beta射线光浊度法、微量振荡天平法等监测技术的方法和原理;指出综合国内外多年的监测经验,PM2.5的在线监测需要经过大量手工经典方法数据作为比对和校验,才能给出有效而高质量的PM2.5监测数据。 相似文献
426.
运用遥感动态监测与地理信息系统技术相结合的方法,以2005年和2009年遥感解译数据、土地侵蚀数据及环境统计数据为数据源,依据《生态环境状况评价技术规范(试行)》(HJ/T192-2006),对山东省17个城市生态环境质量现状及动态变化趋势进行了评价。结果表明:2009年17个城市生态环境状况指数在59.81~78.08之间,生态环境质量状况总体良好;2005-2009年17城市生态环境状况指数变化值在0.06~3.5之间,生态环境质量状况基本稳定。 相似文献
427.
秦皇岛海岸侵蚀动态研究 总被引:2,自引:0,他引:2
刘松涛 《中国环境管理干部学院学报》2012,(1):25-28
利用不同时期的地形图、遥感图片对比,并选取典型海岸岸滩监测剖面实测数据,对海岸侵蚀现状进行了分析和定量计算。分析结果显示,秦皇岛海岸全线处于侵蚀状态,平均蚀退率1.5~4 m/a,根据蚀退率可将秦皇岛海岸划分为严重侵蚀、强侵蚀、侵蚀、微侵蚀、稳定5种岸线侵蚀类型。 相似文献
428.
M. Martínez-Haro M.A. Taggart 《Environmental pollution (Barking, Essex : 1987)》2010,158(7):2485-2489
Hunted mallards (n = 56) were collected in the Ebro Delta (Spain) in 2007-08 to evaluate the use of feces as a non-invasive monitoring method to study lead shot ingestion. The prevalence of Pb shot ingestion in these birds was 28.6%, and similar to that reported before a ban on Pb shot use in 2003. Lead concentrations in terminal intestinal contents were higher in mallards with Pb shot in their gizzard. Feces Pb concentrations >34 μg/g d.w were indicative of Pb shot ingestion, and background Pb levels were <12.5 μg/g d.w. To discriminate between birds ingesting soil Pb, and those ingesting Pb shot, we correlated Al and Pb levels and showed that mallards with ingested Pb shot in the gizzard stood out as outliers within the regression. Feces Pb-Al relationships can be used as a simple non-invasive tool in monitoring programs regarding Pb shot ingestion in birds. 相似文献
429.
430.
Trevor J. Stocki Guichong Li R. Kurt Ungar 《Journal of environmental radioactivity》2010,101(1):68-74
A method of weapon detection for the Comprehensive nuclear-Test-Ban-Treaty (CTBT) consists of monitoring the amount of radioxenon in the atmosphere by measuring and sampling the activity concentration of 131mXe, 133Xe, 133mXe, and 135Xe by radionuclide monitoring. Several explosion samples were simulated based on real data since the measured data of this type is quite rare. These data sets consisted of different circumstances of a nuclear explosion, and are used as training data sets to establish an effective classification model employing state-of-the-art technologies in machine learning. A study was conducted involving classic induction algorithms in machine learning including Naïve Bayes, Neural Networks, Decision Trees, k-Nearest Neighbors, and Support Vector Machines, that revealed that they can successfully be used in this practical application. In particular, our studies show that many induction algorithms in machine learning outperform a simple linear discriminator when a signal is found in a high radioxenon background environment. 相似文献