全文获取类型
收费全文 | 1334篇 |
免费 | 340篇 |
国内免费 | 329篇 |
专业分类
安全科学 | 99篇 |
废物处理 | 28篇 |
环保管理 | 118篇 |
综合类 | 612篇 |
基础理论 | 858篇 |
污染及防治 | 174篇 |
评价与监测 | 78篇 |
社会与环境 | 16篇 |
灾害及防治 | 20篇 |
出版年
2023年 | 16篇 |
2022年 | 32篇 |
2021年 | 32篇 |
2020年 | 32篇 |
2019年 | 45篇 |
2018年 | 114篇 |
2017年 | 96篇 |
2016年 | 97篇 |
2015年 | 109篇 |
2014年 | 127篇 |
2013年 | 173篇 |
2012年 | 141篇 |
2011年 | 144篇 |
2010年 | 109篇 |
2009年 | 96篇 |
2008年 | 87篇 |
2007年 | 69篇 |
2006年 | 63篇 |
2005年 | 54篇 |
2004年 | 50篇 |
2003年 | 38篇 |
2002年 | 31篇 |
2001年 | 28篇 |
2000年 | 28篇 |
1999年 | 25篇 |
1998年 | 19篇 |
1997年 | 16篇 |
1996年 | 24篇 |
1995年 | 18篇 |
1994年 | 14篇 |
1993年 | 13篇 |
1992年 | 17篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有2003条查询结果,搜索用时 890 毫秒
801.
L. G. Wilson Wayne L. Clark Gary G. Small 《Journal of the American Water Resources Association》1973,9(2):243-257
ABSTRACT Raw sewage was metered into a newly-constructed lagoon of the Pima County Department of Sanitation, Tucson, Arizona. Seepage losses were calculated from data on inflow, evaporation and change in storage. Water samples were obtained from shallow suction cups, a 40 ft. and a 60 ft. PVC well and a 100 ft. access tube, all located inside the lagoon. Samples from these wells, together with water samples from the lagoon, were examined for conform organisms and various physical and chemical constituents. Of special concern were transformations in nitrogen. Estimated seepage rates in the lagoon during inundation ranged from 0.20 ft. per day to 0.10 ft. per day. Water level observations in wells reflected the percolation of effluent to the water table, 70 ft. below land surface. Initially, the nitrate ion levels in the suction cup samples were high, manifesting the leaching of indigenous soil nitrogen. With the onset of anaerobic conditions at the base of the lagoon, nitrification was inhibited at the soil surface and ammonia became the predominant form of nitrogen in the soil solution. Sorption of ammonium ion appeared to occur on clay particles in a soil zone of high cation exchange capacity. There were no undesirable microbial or chemical effects of recharge from lagoon seepage on native groundwater quality. 相似文献
802.
Sun-Fu Shih 《Journal of the American Water Resources Association》1978,14(4):942-955
ABSTRACT: A first-order autoregressive model had been modified with the trend and cyclical movements to generate the streamflow sequences. Three main portions were involved in this modified model, i.e., six-year cycle with trend changing; six-year cycle without trend changing; and both annual and six-year cycles with trend changing. The synthetic sequences of monthly streamflow sequences were compared with the historical records obtained from the Kissimmee River basin by using the Chi-Square test for goodness-of-fit. The results indicated that the newly proposed model has a better solution than the original model because the trend and cyclical movements involved in generating sequences are much closer to the historical records. 相似文献
803.
With high performance liquid chromatograph and fluorospectrometry, 1-hydroxypyrene is identified as a metabolite of pyrene in the urine of dogs after intramuscular injection of pyrene. When three successive doses of 1,2 and 5 μmol/kg wt. pyrene administered, urinary excretion of 1-hydroxypyrene reaches the peak level between 24th and 48th hours. Excreted 1-hydroxypyrene consists of only about 0.05% of injected pyrene. 相似文献
804.
本文阐述了利用各种原辅材料使用量和排放系数的物料衡算方法,计算和收取排污费,可基本解决建筑行业在施工中污染物无规律排放问题,对该行业造成的环境污染会有所抑制. 相似文献
805.
VOC removal from contaminated groundwater through membrane pervaporation. (Ⅰ): Water- 1,1,1- trichloroethane system 总被引:1,自引:0,他引:1
1,1,1-trichloroethane(TCA), a common chlorinated organic solvent and volatile organic compound(VOC), was removed from contaminated groundwater by using a bench-scale membrane pervaporation unit. The effects of TCA concentration, temperature, and flow rate on permeation flux and selectivity(a value) of the process were evaluated. In general, higher temperature leads to higher VOC flux but lower selectivity; higher flow rate of TCA feed stream results in higher VOC flux and selectivity, an indication of the effect of concentration polarization; higher TCA feed concentration produces higher TCA permeation, however, the selectivity was virtually unchanged. 相似文献
806.
采用海藻酸钙固定化优势菌Methylibium petroleipmhilu PM1降解甲基叔丁基醚(MTBE).结果表明,固定化细胞对于pH值、温度、底物浓度的适应范围变宽,在pH5~10、温度25~40℃、底物浓度10~500mg/L时,固定化细胞具有较高的MTBE生物降解活性;30℃储存降解活性半衰期为96h;重复使用30批活性没有明显降低;扫描电镜观察表明,细胞在海藻酸钙包埋载体中能良好地生长和繁殖.固定化细胞降解MTBE反应符合零级动力学特征. 相似文献
807.
GM(1,1)模型预测城市区域环境噪声的应用 总被引:1,自引:0,他引:1
介绍了重庆市主城区区域环境噪声污染现状,根据1996~2002年区域环境噪声的监测数据,建立了GM(1,1)灰色预测模型,通过预测探讨了区域环境噪声的变化规律.结果表明,主城区未来几年区域环境噪声呈上升趋势,2003年预测值为57.8分贝. 相似文献
808.
CHENG Shu-pei ZHONG Zhi-hui LU Peng CHEN Jun ZHU Jian-zhong JUEZi-long 《环境科学学报(英文版)》2000,12(4):394-397
IntroductionPhanerochaetechrysosporium (PC)isoneoftheunusualwhiterotfungithatitisabletomineralizethecompoundofnativelignin .Anditalsocandegradealmostallhazardousorganicpollutantsincludinggeneticmutagenicagentssuchaschlorinatedorganiccompounds,polycyclic… 相似文献
809.
Photoreaction of particle-bound 1-nitropyrehe (1-NP) under simulated atmospheric condition has been studied. When 1-NP coated on the surface of silica gel was suspended in a stream of nitrogen, oxygen or air, respectively, and exposed to intensive light of xenon lamp, photochemical reaction took place. The result of kinetic study showed it to be of the second order. The photoreaction products were identified by off-line HPLC/MS as 1,6-pyrenequinone, 1,8-pyrenequinone, trinitro-hydroxypyrene, dinitrohydroxypyrene, 6,6'- dipyrenenone, etc. The mutagenicity of photochemical reaction products is higher in oxygen and air, and lower in nitrogen than that of the precursor 1-NP, as detected by the Ames Bioassay. 相似文献
810.
We describe our experiences of prenatal diagnosis of alpha-1-antitrypsin deficiency using closely linked polymorphisms detected by Southern blotting and the polymerase chain reaction. Prenatal diagnosis was carried out for 17 pregnancies from 15 couples. 相似文献