全文获取类型
收费全文 | 699篇 |
免费 | 91篇 |
国内免费 | 422篇 |
专业分类
安全科学 | 138篇 |
废物处理 | 55篇 |
环保管理 | 54篇 |
综合类 | 659篇 |
基础理论 | 114篇 |
污染及防治 | 163篇 |
评价与监测 | 19篇 |
社会与环境 | 4篇 |
灾害及防治 | 6篇 |
出版年
2024年 | 1篇 |
2023年 | 18篇 |
2022年 | 24篇 |
2021年 | 39篇 |
2020年 | 31篇 |
2019年 | 34篇 |
2018年 | 31篇 |
2017年 | 28篇 |
2016年 | 46篇 |
2015年 | 57篇 |
2014年 | 56篇 |
2013年 | 56篇 |
2012年 | 75篇 |
2011年 | 70篇 |
2010年 | 49篇 |
2009年 | 61篇 |
2008年 | 38篇 |
2007年 | 76篇 |
2006年 | 64篇 |
2005年 | 45篇 |
2004年 | 30篇 |
2003年 | 44篇 |
2002年 | 25篇 |
2001年 | 26篇 |
2000年 | 24篇 |
1999年 | 35篇 |
1998年 | 28篇 |
1997年 | 21篇 |
1996年 | 12篇 |
1995年 | 15篇 |
1994年 | 12篇 |
1993年 | 15篇 |
1992年 | 7篇 |
1991年 | 5篇 |
1990年 | 4篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
排序方式: 共有1212条查询结果,搜索用时 31 毫秒
891.
The influence of the nonionic surfactant Tween 80 on pentachlorophenol (PCP) oxidation catalyzed by horseradish peroxidase was studied. The surfactant was tested at concentrations below and above its critical micelle concentration (CMC). Enhancement of PCP removal was observed at sub-CMCs. The presence of Tween 80 in the reaction mixture reduced enzyme inactivation which occurred through a combination of free radical attack and sorption by precipitated products. A simple first-order model was able to simulate time profiles for enzyme inactivation in the presence or absence of Tween 80. At supra-CMCs, the surfactant caused noticeable reductions in PCP removal, presumably through micelle partitioning of PCP which precluded the hydrophobic PCP molecule from interacting with the enzyme. 相似文献
892.
Hydrothermal decomposition of pentachlorophenol in subcritical and
supercritical water with sodium hydroxide addition 总被引:1,自引:0,他引:1
Hydrothermal decomposition of pentachlorophenol (PCP, C6HC150), as the probable human carcinogen, was investigated in a tubular reactor under subcritical and supercritical water with sodium hydroxide (NaOH) addition. The experiments were conducted at a temperature range of 30(0-420℃ and a fixed pressure of 25 MPa, with a residence time that ranged from 10 s to 70 s. Under the reaction conditions, the initial PCP concentrations were varied from 0.25 to 1.39 mmol/L, and the NaOH concentrations were varied from 2.5 to 25 times of the concentrations of PCP. The result of this study showed that PCP conversion in supercritical water was highly dependent on the reaction temperature, residence time, and NaOH concentration. PCP conversion in subcritical water is, however, only dependent on reaction temperature. NaOH concentration and residence times were found to have little effect on PCP conversion in subcritical condition. It was found that NaOH concentration affected the dechlorinations of PCP in the supercritical water. The intermediates detected were proposed to be tetrachlorophenol and trichlorophenol, respectively. 相似文献
893.
给水水质分析中CODMn测定值是评价水质的重要指标之一,现行CODMn测定方法其检测范围为0.5—4.5mg/L,而纯净水、矿泉水、饮用净水等的CODMn低于0.5mg/L,本文提出的KMnO4褪色法可测0.02mg/LCODMn。 相似文献
894.
Truncation errors in finite difference models for solute transport equation with first-order reaction 总被引:1,自引:0,他引:1
The truncation errors associated with finite difference solutions of the advection-dispersion equation with first-order reaction are formulated from a Taylor analysis. The error expressions are based on a general form of the corresponding difference equation and a temporally and spatially weighted parametric approach is used for differentiating among the various finite difference schemes. The numerical truncation errors are defined using Peclet and Courant numbers and a new Sink/Source dimensionless number. It is shown that all of the finite difference schemes suffer from truncation errors. In particular it is shown that the Crank–Nicolson approximation scheme does not have second order accuracy for this case. The effects of these truncation errors on the solution of an advection–dispersion equation with a first order reaction term are demonstrated by comparison with an analytical solution. The results show that these errors are not negligible and that correcting the finite difference scheme for them results in a more accurate solution. 相似文献
895.
896.
潮湿气氛下Ca(OH)2与SO2反应动力学研究 总被引:5,自引:0,他引:5
本文用固定床积分反应器研究潮湿气氛下Ca(OH)2与SO2的反应动力学。 相似文献
897.
Donald Dean Adrian Thomas G. Sanders Emerald M. Roider 《Journal of the American Water Resources Association》1999,35(5):1191-1200
Several published BOD data sets are examined to show that approximately half of them are described best in the least squares sense by treating the BOD equation as being of the three-halves order instead of first order. A dissolved oxygen (DO) sag equation for a stream is developed in which the BOD is described as a three-halves order reaction. The time when the minimum DO concentration occurs is calculated numerically. The DO sag model applied to example problems shows that an increase in the BOD reaction rate constant results in a smaller minimum DO concentration and a decrease in the time to reach the minimum DO. 相似文献
898.
899.
900.
苯甲酸类光催化降解和羟基自由基反应的关系 总被引:2,自引:0,他引:2
研究了13种苯甲酸类化合物在固定膜平板反应器中的光催化降解,探讨了光降解速率与化合物结构之间的定量关系(QSAR),同时分析了苯甲酸类化合物和羟基自由基反应的速率常数与结构的关系结果表明,Hammett常数(σ)和摩尔对数溶解度(lgS)是影响本甲酸类光降解速率lgK的重要因素,其定量关系式为:lgK=-0.309σ+0.125lgS-2.612,苯甲酸类与羟基自由基反应的定量关系式为lgKOH=-0.414σ+9.816,证实了羟基自由基在本甲酸类光催化过程中的重要作用. 相似文献