全文获取类型
收费全文 | 1961篇 |
免费 | 258篇 |
国内免费 | 734篇 |
专业分类
安全科学 | 347篇 |
废物处理 | 47篇 |
环保管理 | 172篇 |
综合类 | 1492篇 |
基础理论 | 282篇 |
污染及防治 | 226篇 |
评价与监测 | 149篇 |
社会与环境 | 154篇 |
灾害及防治 | 84篇 |
出版年
2024年 | 16篇 |
2023年 | 59篇 |
2022年 | 158篇 |
2021年 | 156篇 |
2020年 | 178篇 |
2019年 | 127篇 |
2018年 | 143篇 |
2017年 | 176篇 |
2016年 | 123篇 |
2015年 | 137篇 |
2014年 | 120篇 |
2013年 | 175篇 |
2012年 | 184篇 |
2011年 | 174篇 |
2010年 | 163篇 |
2009年 | 134篇 |
2008年 | 137篇 |
2007年 | 125篇 |
2006年 | 104篇 |
2005年 | 74篇 |
2004年 | 52篇 |
2003年 | 47篇 |
2002年 | 48篇 |
2001年 | 39篇 |
2000年 | 41篇 |
1999年 | 26篇 |
1998年 | 8篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 5篇 |
1993年 | 4篇 |
1992年 | 4篇 |
1991年 | 1篇 |
排序方式: 共有2953条查询结果,搜索用时 0 毫秒
51.
52.
Zhiqiang Nie Zhenwu Tang Xiaohua Zhu Yufei Yang Haihui Fu Qingqi Die Qi Wang Qifei Huang 《Environmental science and pollution research international》2013,20(12):8751-8762
The concentrations, compositional profiles, and possible sources of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/PCDF) in water column and surface sediment samples from the lower reaches of the Yangtze River were investigated, and the potential risks posed by these chemicals were evaluated. Concentrations of the 17 2,3,7,8-substituted PCDD/PCDF in the water and sediment samples ranged from 0.45 to 10.0 pg TEQ/L (mean 2.34 pg TEQ/L) and from 0.31 to 51 pg TEQ/g dw (mean 5.25 pg TEQ/g dw), respectively. Water and sediments from the Nanjing–Nantong sections of the Yangtze River were found to have elevated PCDD/PCDF levels, and the PCDD/PCDF TEQ concentrations in 13 sediment samples exceeded the probable effect levels (PEL), above which adverse biological effects are likely. Multivariate statistical analysis indicated that the principal PCDD/PCDF contamination source for the water and sediment was the production and use of pentachlorophenol (PCP) or sodium pentachlorophenate (PCP-Na). PCDD/PCDF concentrations were stable over time near the Yangtze River Estuary but had increased sharply in recent decades in the Nanjing–Nantong section, which will have been related to the growth in industrial activities and other anthropogenic PCDD/PCDF sources. Total organic carbon (TOC) and PCDD/PCDF concentrations correlated significantly (R?=?0.474, P?<?0.01), suggesting that TOC plays an important role in the transport and re-distribution of PCDD/PCDF in the Yangtze River basin. 相似文献
53.
54.
55.
56.
Hu Z 《Chemosphere》2008,72(2):312-318
The biokinetics of attached and suspended bacteria are an essential component of activated sludge models, anaerobic digestion models and biofilm models. These parameters are often assumed or “confirmed” based on the goodness-of-fit of the bioprocess models. Using a microbial fuel cell with a baffled reactor chamber, the attached- and mixed-growth microbial decay coefficients were evaluated under anaerobic conditions. The capability for real-time voltage recording allows easy and accurate measurement of the anaerobic microbial decay coefficients (bL, lysis-regrowth approach), which were determined to be 0.11 ± 0.01 and 0.15 ± 0.01 d−1 for attached (to anode) and mixed (present in the anode chamber) growth microorganisms, respectively. The corresponding half-saturation constants using glucose as a substrate were 204 ± 10 and 123 ± 1 mg COD l−1. Hence, like an oxygen uptake rate-based approach to measure the microbial kinetics under aerobic conditions, the electrochemical recording provides an attractive method to measure anaerobic microbial decay coefficients. 相似文献
57.
通过实验研究了格栅类通透性吊顶对水喷淋控火性能的影响,并利用燃料燃尽时间来计算控火有效性因子来量化这种影响.研究结果表明:格栅会降低水喷淋控火性能,与格栅类吊顶形式、喷头安装高度和工作压力流量有关.在确定的吊顶形式和尺寸下,存在着对控火性能影响最大的喷头安装高度.在实际工程应用中应根据具体格栅特性,合理设计喷头安装高度,以降低格栅的不利影响,保证水喷淋的控火有效性. 相似文献
58.
59.
60.