全文获取类型
收费全文 | 6573篇 |
免费 | 725篇 |
国内免费 | 2148篇 |
专业分类
安全科学 | 789篇 |
废物处理 | 267篇 |
环保管理 | 469篇 |
综合类 | 4483篇 |
基础理论 | 1020篇 |
环境理论 | 2篇 |
污染及防治 | 1197篇 |
评价与监测 | 462篇 |
社会与环境 | 378篇 |
灾害及防治 | 379篇 |
出版年
2024年 | 33篇 |
2023年 | 151篇 |
2022年 | 443篇 |
2021年 | 383篇 |
2020年 | 410篇 |
2019年 | 293篇 |
2018年 | 304篇 |
2017年 | 317篇 |
2016年 | 318篇 |
2015年 | 411篇 |
2014年 | 477篇 |
2013年 | 570篇 |
2012年 | 625篇 |
2011年 | 618篇 |
2010年 | 528篇 |
2009年 | 422篇 |
2008年 | 447篇 |
2007年 | 449篇 |
2006年 | 426篇 |
2005年 | 282篇 |
2004年 | 211篇 |
2003年 | 190篇 |
2002年 | 218篇 |
2001年 | 178篇 |
2000年 | 180篇 |
1999年 | 105篇 |
1998年 | 70篇 |
1997年 | 83篇 |
1996年 | 77篇 |
1995年 | 54篇 |
1994年 | 45篇 |
1993年 | 29篇 |
1992年 | 36篇 |
1991年 | 22篇 |
1990年 | 13篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1981年 | 2篇 |
排序方式: 共有9446条查询结果,搜索用时 12 毫秒
491.
依据2009年7月至2012年2月连续3年对杭州城区环境空气中二英(PCDD/Fs)采样分析结果得知,杭州城区环境空气中二英毒性当量质量浓度变化范围为0.13~0.55 pg TEQ/m3,均值为0.34 pg TEQ/m3。城区环境空气中二英浓度季节变化不显著,夏季略低于冬季;城区范围内不同功能区之间二英浓度差别不显著;连续3年监测结果未显现二英年度变化趋势。沙尘暴天气环境空气中二英浓度显著增高,日常天气和烟花爆竹集中燃放天气环境空气中二英形态分布存在明显区别,烟花爆竹集中燃放期间八氯代二苯并-对-二英(OCDD)占总质量浓度比例显著提高。利用IBM SPSS Statistics 19.0统计软件对24个监测结果聚类分析发现,杭州城区环境空气中二英的同类物分布具有明显的“源”分布特征。 相似文献
492.
2015年11月1—4日,哈尔滨市及周边地区发生了连续的灰霾天气,颗粒物浓度急剧升高。污染发生时,监测仪器均布设在哈尔滨市区上风向30 km处(哈尔滨市双城区)并开展了连续96 h的监测分析。综合利用气象观测资料,3D可视激光雷达监测资料及地面空气污染监测资料分析了灰霾天气发生的气象条件和污染边界层特征,根据哈尔滨市双城区大气污染物排放源谱库对主要成分进行来源解析,结合颗粒物质量浓度和气象条件研究了秸秆焚烧对灰霾天气的影响。结果表明,灰霾天气持续期间,夜间生物质燃烧源成为该地区颗粒物的第二大源;秸秆焚烧产生的大气污染物,由于地面长时间静风,污染边界层降低等原因,致使本地污染物累积、不易扩散,加剧了本次污染。 相似文献
493.
494.
495.
Distribution,sources, and ecological risk assessment of SVOCs in surface sediments from Guan River Estuary,China 总被引:1,自引:0,他引:1
Xinran He Xiaojuan Song Yong Pang Yiping Li Binlin Chen Zhihua Feng 《Environmental monitoring and assessment》2014,186(7):4001-4012
The contamination of semi-volatile organic compounds (SVOCs) in the surface sediments of the Guan River Estuary, China was fully investigated. Total concentrations of 56 species of SVOCs ranged from 132 to 274 ng/g with an average of 186 ng/g (dry weight). Polycyclic aromatic hydrocarbon (PAH) concentrations were positively correlated with clay content and negatively correlated with sediment grain size. Source identification indicated that PAHs originated mainly from pyrolytic sources. However, intense ship traffic in the estuary may provide sources of petrogenic PAHs. Organochlorine pesticides (OCPs) mainly originated from direct input of dichlorodiphenyltrichloroethanes (DDTs) during some industrial processes. The SVOC concentrations were also compared with International Sediments Quality Guidelines and Sediments Quality Criteria, and the results indicated that negative biological impacts may originate from high concentrations of FLO, p,p′-DDE, and total DDTs. 相似文献
496.
便携式GC/MS热脱附法直接测定环境空气中挥发性有机物 总被引:3,自引:1,他引:2
采用便携式气相色谱/质谱联用热脱附法直接测定环境空气中的挥发性有机物,优化了试验条件。方法在5×10-9~100×10-9范围内线性良好,39种化合物的检出限为1.1μg/m3~19μg/m3,标准气体平行测定的RSD≤11.0%,回收率在80%~120%之间。 相似文献
497.
Lan Q Cui K Zeng F Zhu F Liu H Chen H Ma Y Wen J Luan T Sun G Zeng Z 《Environmental monitoring and assessment》2012,184(8):4921-4929
Phthalate esters (PAEs) were examined in indoor and outdoor dust samples from the subtropical city of Guangzhou, China. The ∑(16)PAEs concentrations ranged from 121 to 3,223 μg g(-1) dust, with the median concentration of 840 μg g(-1) dust. Significantly higher concentrations of PAEs in dust samples were found in offices where electrical and electronic devices, carpet pads, and office furniture were widely used. Of the 16 PAEs, diisobutyl phthalate (DiBP), di-n-butyl phthalate (DnBP), and di(2-ethylhexyl) phthalate (DEHP) dominated the PAEs in indoor and outdoor dust samples, and accounted for >96.8% and >93.1% of the ∑(16)PAEs concentrations, respectively. The median daily inhalation exposure of ∑(16)PAEs were 3.53 and 0.247 μg kg(-1) body weight day(-1), and at the 95(th) percentile were 7.62 and 0.530 μg kg(-1) body weight day(-1), up on the measured concentrations and estimated dust ingestion rates, respectively, for toddles and adults. The ubiquitous distribution of PAEs as noted in this study suggests the need for detailed assessment of PAEs concentrations using more sites and to further investigate the factors influencing PAEs exposure in China. 相似文献
498.
Li YX Han W Yang M Feng CH Lu XF Zhang FS 《Environmental monitoring and assessment》2012,184(8):5035-5041
Concentrated animal feeding operations have been recognized as one of the most important contributors of natural estrogens which show significant endocrine-disrupting properties in aquatic environments. In this study, the concentrations of 17α-estradiol (17α-E2), 17β-estradiol (17β-E2), estrone (E1), and estriol (E3) in several matrices, including soils (surface and deep), sediments (surface and deep), and groundwaters, around a typical dairy farm were surveyed using gas chromatography/mass spectrometry. Of the two farmlands, surface and subsurface sediments in waste lagoon and along effluent drainage drench, the concentrations of 17α-E2, 17β-E2, and E1 ranged from below detection limit to the highest level of 6.60 μg/kg, except that E3 was not detectable. Three estrogens of 17α-E2, 17β-E2, and E1 with the concentrations of 3.18-31.61 ng/L were observed in two groundwater samples. The results clearly demonstrated the vertical migration and horizontal transport of estrogens in the investigated area. Within 750-m distance, it was observed the attenuation of 17α-E2, 17β-E2, and E1 along the effluent route and the horizontal migration of estrogens was less than 1,350 m in this survey. 相似文献
499.
The accelerated industrialization and urbanization in the last three decades around the Pearl River Delta within Guangdong Province in China have led to serious concerns about the impacts on the aquatic environment. In the present study, the genotoxicity of the sediments collected from the Pearl River was evaluated by micronucleus (MN) assay with Vicia faba root tip cells, and the 16 EPA priority polycyclic aromatic hydrocarbons (PAHs) and heavy metals (HMs, including Cr, Cu, As, Se, Cd, Hg, and Pb) in the sediments were determined respectively by GC-MS, inductively coupled plasma mass spectrometry, and inductively coupled plasma atomic emission spectrometry. The results showed that there were significant increases of MN frequencies observed in the sediment-exposed groups, compared with the negative group (P?0.05, P?0.01), indicating that the sediments clearly had genotoxicity to the V. faba root cells. The total concentrations of the priority PAHs (250-13,656 ng g(-1), dry weight) and HMs (As, 22,770-36,639 μg kg(-1); Cr, 39,333-133,343 μg kg(-1); Cu, 36,145-159,270 μg kg(-1); Pb, 51,210-166,642 μg kg(-1); Cd, 475.4-1,818.9 μg kg(-1); Hg, 59.9-460.8 μg kg(-1); and Se, 331.7-1,250.4 μg kg(-1), dry weight) were close to those obtained from other urbanized and industrialized areas, which have been considered moderately polluted. There was a clear positive correlation between MN potency and the molar concentrations of Hg and Pb in the sediments (Hg, r?=?0.94; Pb, r?=?0.91), suggesting that Hg and Pb were the most important factors that posed the sediments higher genotoxicity to V. faba root cells. Our results suggested that both biological and chemical approaches are necessary to be included in a battery of tests to assess the eco-environmental risks of sediments. 相似文献
500.