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   1353篇
  免费   72篇
  国内免费   493篇
安全科学   92篇
废物处理   60篇
环保管理   149篇
综合类   725篇
基础理论   244篇
污染及防治   449篇
评价与监测   81篇
社会与环境   58篇
灾害及防治   60篇
  2024年   2篇
  2023年   27篇
  2022年   84篇
  2021年   61篇
  2020年   61篇
  2019年   53篇
  2018年   62篇
  2017年   80篇
  2016年   59篇
  2015年   68篇
  2014年   97篇
  2013年   132篇
  2012年   116篇
  2011年   137篇
  2010年   84篇
  2009年   88篇
  2008年   83篇
  2007年   76篇
  2006年   85篇
  2005年   60篇
  2004年   42篇
  2003年   33篇
  2002年   53篇
  2001年   38篇
  2000年   47篇
  1999年   37篇
  1998年   19篇
  1997年   27篇
  1996年   15篇
  1995年   17篇
  1994年   11篇
  1993年   20篇
  1992年   11篇
  1991年   10篇
  1990年   4篇
  1989年   3篇
  1988年   2篇
  1987年   4篇
  1986年   1篇
  1984年   1篇
  1983年   2篇
  1982年   2篇
  1973年   1篇
  1958年   1篇
  1920年   1篇
  1919年   1篇
排序方式: 共有1918条查询结果,搜索用时 15 毫秒
151.
微絮凝-超滤工艺处理微污染水源水的中试研究   总被引:2,自引:0,他引:2  
进行了微絮凝.超滤工艺处理微污染水源水的中试研究。试验结果表明:在微絮凝-超滤工艺中,相同混凝剂投加量(相同金属摩尔浓度)下铁盐比铝盐的混凝效果好;微絮凝-超滤工艺的最佳絮凝时间为120s左右;最佳混凝剂投加量为2.2mg/L(以Fe计)。微絮凝-超滤工艺在改善出水水质和缓解膜污染方面均优于直接超滤工艺。微絮凝-超滤工艺的出水水质均符合建设部《城市供水水质标准》(CJ/T206-2005)要求。  相似文献   
152.
城市污水生物处理系统中微生物酶的活性及其分布   总被引:1,自引:0,他引:1  
李茵  罗翠  Chr 《环境污染与防治》2007,29(5):333-335
通过水解模式底物进行分光光度测定的方法,研究了城市污水生物处理系统中微生物酶的活性.选取亮氨酸氨基肽酶、β-葡萄糖苷酶、碱性磷酸酶和脂酶等胞外酶进行分析,结果发现4种胞外酶的平均活性在31.O~88.5 μmol/(L·h),其中76.9%~94.8%的酶活性分布在活性污泥中,说明绝大部分胞外酶是与细胞相连或固定在细胞外多聚絮体基质里.混合水样和出水水样中的DOC几乎相等,而各胞外酶与DOC不存在任何显著的相关关系.增加NO3-浓度可提高亮氨酸氨基肽酶和β-葡萄糖苷酶的活性,但对碱性磷酸酶和脂酶却有明显的抑制作用.  相似文献   
153.
城市污水处理厂除臭技术   总被引:10,自引:0,他引:10  
介绍了城市污水处理厂臭气来源、成分及产量。针对目前国内外除臭技术的研究和发展情况,分析了污水处理厂的各种物理、化学和生物除臭方法的技术原理、优缺点和应用现状。结合日本城市污水处理厂的运行实际,重点介绍了一种不产生臭气的新技术——腐殖活性污泥法的工艺流程、特点及其应用现状。  相似文献   
154.
根据锅炉烟尘测试方法(GB 5468-91)及锅炉大气污染物排放标准(GB 13271-2001),在不同风门的工况下,分别对设计的双层炉排秸秆成型燃料锅炉污染物排放规律进行试验.试验表明,在较好工况下,双层炉排锅炉排烟中CO等中间产物及烟尘含量低于单层炉排锅炉,其排烟中CO、NOx、SO2和烟尘浓度等指标远远低于燃煤锅炉,符合国家关于工业锅炉大气污染物排放标准要求,有较好环保效益.  相似文献   
155.
An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h−1 m−2 (30–60 ng h−1 per g dry plant––540–1080 ng h−1 per plant), in total. Limonene, -thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (MS) and temperature coefficients were determined: βlimonene=0.108 K−1 and MS=14.57 μg h−1 m−2; βsabinene=0.095 K−1 and MS=5.39 μg h−1 m−2.

The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.  相似文献   

156.
Wang X  Yin C  Wang L 《Chemosphere》2002,46(7):1045-1051
Inhibition of growth of the yeast Saccharomyces cerevisiae (Cmiz, the minimum concentration that produced a clear inhibition zone within 12 h) for 24 nitroaromatic compounds was investigated and a quantitative structure-activity relationship (QSAR) developed based on hydrophobicity expressed as the l-octanol/water partition coefficient in logarithm form, log K(ow), electrophilicity based on the energy of the lowest unoccupied orbital (E(lumo)). All nitrobenzene derivatives exhibited enhanced reactive toxicity than baseline. The toxicities of mono-nitrobenzenes and di-nitrobenzenes were elicited by different mechanisms of toxic action. For mono-nitro-derivatives, both significant log K(ow) based and strong E(lumo)-dependent relationships were observed indicating that their toxicities were affected both by the penetration process and the interaction with target sites of interaction. The toxicities of di-nitrobenzenes were greater than mono-nitrobenzenes and no log K(ow)-dependent but highly significant E(lumo)-based relationship was obtained. This suggests that toxicity of di-nitrobenzenes was highly electrophilic and involved mainly their in vivo electrophilic interaction with biomacromolecules. In an effort to model the elevated toxicity of all nitrobenzenes, a response-surface analysis was performed and this resulted in a highly predictive two-variable QSAR without reference to their exact mechanisms (Cmiz = 0.41 log K(ow) - 0.89 E(lumo) - 0.46, r2 = 0.87, Q2 = 0.86, n = 24).  相似文献   
157.
Lin Z  Zhong P  Yin K  Wang L  Yu H 《Chemosphere》2003,52(7):1199-1208
A QSAR model is successfully proposed to predict the toxicity effect on Photobacterium phosphoreum by nonpolar-narcotic-chemical mixtures and/or polar-narcotic-chemical mixtures. For nonpolar-narcotic-chemical mixtures and polar-narcotic-chemical mixtures, their corresponding hydrophobicity-based QSAR models are derived from regression analysis. Comparison of these two QSAR models make us believe that it is the joint effect of hydrogen bond in polar-narcotic-chemical mixture that leads to the difference between these two models. Such joint effect of hydrogen bond can be quantified as AMH and BMH by using the different partition coefficients of mixtures in various organic phase/water systems. And the regression analysis results convinced us that the introduction of AMH does improve the quality of the QSAR model with r2=0.948, S.E.=0.166 and F=745.201 at P=0.000 for total 84 mixtures.  相似文献   
158.
柱生物曝气法吸附处理含铬废水   总被引:7,自引:0,他引:7  
利用复合生物吸附剂FY01与活性污泥作为吸附材料,探讨了柱式生物曝气法对高浓度含铬电镀废水的生物吸附效果。研究结果表明,FY01性能稳定,耐进水pH冲击能力较强。当进水pH=2—5、流速为500mL/h时,10gFY01和5g活性污泥联合处理60.4mg/L含铬电镀废水2h后,铬的去除率达78%以上;在4℃冰箱和23—28℃实验室保存50d的FY01对铬的去除分别在78%~83%和77%-84%之间。柱式生物曝气吸附法对含铬废水的处理效果理想,运行稳定。串联处理2000mL总Cr、Cu^2+和COD浓度分别为60.4、4.51和48.2mg/L的电镀废水2h后,去除率分别高达92.1%、99.2%和71.4%。  相似文献   
159.
分析了焦作某电厂堆灰场附近浅层地下水中Cr6+ 的形成原因。根据该区水文地质背景 ,提出在地下污染水羽的下游建可渗透反应墙的漏斗 -通道系统 ,用对Cr6+ 有很高去除效率的风化煤作为反应材料 ,使污染水羽流经此系统时有效去除地下水中的Cr6+ ,达到净化的目的  相似文献   
160.
An increasing percentage of agricultural land in Germany is used for oil seed plants. Hence, rape has become an important agricultural plant (in Saxony 1998: 12% of the farmland) in the recent years. During flowering of rape along with intensive radiation and high temperatures, a higher production and emission of biogenic VOC was observed. The emissions of terpenes were determined and more importantly, high concentrations of organic carbonyl compounds were observed during this field experiment. All measurements of interest have been carried out during two selected days with optimal weather conditions. It is found that the origin or the mechanism of formation of different group of compounds had strong influence on the day to day variation of their concentrations. The emission flux of terpenes from flowering rape plants was determined to be 16–32 μg h−1 m−2 (30–60 ng h−1 per g dry plant––540–1080 ng h−1 per plant), in total. Limonene, α-thujene and sabinene were the most important compounds (about 60% of total terpenes). For limonene and sabinene reference emission rates (MS) and temperature coefficients were determined: βlimonene=0.108 K−1 and MS=14.57 μg h−1 m−2; βsabinene=0.095 K−1 and MS=5.39 μg h−1 m−2.The detected carbonyl compound concentrations were unexpectedly high (maximum formaldehyde concentration was 18.1 ppbv and 3.4 ppbv for butyraldehyde) for an open field. Possible reasons for these concentrations are the combination of primary emission from the plants induced by high temperature and high ozone stress, the secondary formation from biogenically and advected anthropogenically emitted VOC at high radiation intensities and furthered by the low wind speeds at this time.  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