全文获取类型
收费全文 | 262篇 |
免费 | 2篇 |
国内免费 | 29篇 |
专业分类
安全科学 | 17篇 |
废物处理 | 8篇 |
环保管理 | 14篇 |
综合类 | 73篇 |
基础理论 | 26篇 |
污染及防治 | 107篇 |
评价与监测 | 34篇 |
社会与环境 | 9篇 |
灾害及防治 | 5篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 8篇 |
2020年 | 5篇 |
2019年 | 2篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 12篇 |
2015年 | 5篇 |
2014年 | 19篇 |
2013年 | 27篇 |
2012年 | 20篇 |
2011年 | 25篇 |
2010年 | 11篇 |
2009年 | 25篇 |
2008年 | 23篇 |
2007年 | 22篇 |
2006年 | 10篇 |
2005年 | 5篇 |
2004年 | 9篇 |
2003年 | 9篇 |
2002年 | 5篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 5篇 |
1998年 | 2篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有293条查询结果,搜索用时 171 毫秒
121.
氢化物-原子荧光光谱法测定土壤中硒 总被引:7,自引:0,他引:7
通过对比实验选择了最佳的仪器测定条件、主要试剂的浓度及土壤的前处理方式。实验结果表明:采用HN03-HClO4酸体系在沙浴中对土壤进行消解,硒的检出限为0.02mg/kg;线性范围为0ug/L~200ug/L;平均回收率可达100%~103%。方法经土壤国家标准物质中硒的测定验证,结果与标准值相符。 相似文献
122.
123.
Changes in visibility with PM2.5 composition and relative humidity at a background site in the Pearl River Delta region 总被引:2,自引:0,他引:2
Xiaoxin Fu Xinming Wang Qihou Hu Guanghui Li Xiang Ding Yanli Zhang Quanfu He Tengyu Liu Zhou Zhang Qingqing Yu Ruqing Shen Xinhui Bi 《环境科学学报(英文版)》2016,28(2):10-19
In fall–winter, 2007–2013, visibility and light scattering coefficients(b sp) were measured along with PM_(2.5)mass concentrations and chemical compositions at a background site in the Pearl River Delta(PRD) region. The daily average visibility increased significantly(p 0.01) at a rate of 1.1 km/year, yet its median stabilized at ~13 km. No haze days occurred when the 24-hr mean PM_(2.5)mass concentration was below 75 μg/m~3. By multiple linear regression on the chemical budget of particle scattering coefficient(b sp), we obtained site-specific mass scattering efficiency(MSE) values of 6.5 ± 0.2, 2.6 ± 0.3, 2.4 ± 0.7 and 7.3 ± 1.2 m2/g,respectively, for organic matter(OM), ammonium sulfate(AS), ammonium nitrate(AN) and sea salt(SS). The reconstructed light extinction coefficient(b ext) based on the Interagency Monitoring of Protected Visual Environments(IMPROVE) algorithm with our site-specific MSE revealed that OM, AS, AN, SS and light-absorbing carbon(LAC) on average contributed 45.9% ± 1.6%,25.6% ± 1.2%, 12.0% ± 0.7%, 11.2% ± 0.9% and 5.4% ± 0.3% to light extinction, respectively.Averaged b ext displayed a significant reduction rate of 14.1/Mm·year(p 0.05); this rate would be 82% higher if it were not counteracted by increasing relative humidity(RH) and hygroscopic growth factor(f(RH)) at rates of 2.5% and 0.16/year-1(p 0.01), respectively, during the fall–winter, 2007–2013. This growth of RH and f(RH) partly offsets the positive effects of lowered AS in improving visibility, and aggravated the negative effects of increasing AN to impair visibility. 相似文献
124.
Yanan Tang Ying Xu Feng Li Lindsay Jmaiff Steve E.Hrudey Xing-Fang Li 《环境科学学报(英文版)》2016,28(4):259-266
A broad range of organic compounds are known to exist in drinking water sources and serve as precursors of disinfection byproducts(DBPs).Epidemiological findings of an association of increased risk of bladder cancer with the consumption of chlorinated water has resulted in health concerns about DBPs.Peptides are thought to be an important category of DBP precursors in water.However,little is known about the actual presence of peptides and their DBPs in drinking water because of their high sample complexity and low concentrations.To address this challenge and identify peptides and non-chlorinated/chlorinated peptide DBPs from large sets of organic compounds in water,we developed a novel high throughput analysis strategy,which integrated multiple solid phase extraction(SPE),high performance liquid chromatography(HPLC)separation,and non-target identification using precursor ion exclusion(PIE)high resolution mass spectrometry(MS).After MS analysis,structures of candidate compounds,particularly peptides,were obtained by searching against the Human Metabolome Database(HMDB).Using this strategy,we successfully detected 625 peptides(out of 17,205 putative compounds)and 617 peptides(out of 13,297)respectively in source and finished water samples.The source and finished water samples had 501 peptides and amino acids in common.The remaining 116 peptides and amino acids were unique to the finished water.From a subset of 30 putative compounds for which standards were available,25 were confirmed using HPLC-MS analysis.By analyzing the peptides identified in source and finished water,we successfully confirmed three disinfection reaction pathways that convert peptides into toxic DBPs. 相似文献
125.
126.
The influence of aluminium cation as a strong electrophilic centre on the thermolysis of chlorophenols chemisorbed on Al(OH)3 surface was investigated. If thermolysis is carried out at 300 °C the spontaneous rupture of the bond between aluminium and oxygen of phenol takes place in the temperature range of 260–280 °C. The thermolysis of chlorophenoxy aluminium compounds occurs through homolytic and heterolytic bond cleavage. In the case of heterolytic cleavage the leaving chlorophenoxy anion causes a simultaneous formation of the aluminium cation, which is the driving force for the rearrangement of the unstable intermediate. By homolytic cleavage of the Al–O bond the chlorophenoxy radical is formed. The isolation of reaction products of the thermolysis of the system Al(OH)3/2,4,6-trichlorophenol gave five isomers of dimeric compounds of resonance stabilised 2,4,6-trichlorophenoxy radical. The compounds are stable in nonaqueous, aprotic solution, but they are very sensitive to acid catalysis. They quickly transform into aromatic hydroxydiphenyl ethers. The process of dechlorination and aromatisation of cyclohexadienone dimers gives PCDD/PCDF. 相似文献
127.
The use of column experiments, usually performed to better approximate field conditions, may provide information that is not available from batch experiments. In such experiments heavy metals are often adsorbed until saturation followed by desorption experiments. When the affinity of the metal to soil is high, the retention factor (R) could be greater than thousands and the duration of experiments can become impractically long. In order to use reasonable laboratory time, the flow rate should be increased or the column size decreased. The increase in flow rate produces undesirable kinetic and dispersion effects, so we used very small soil columns (pore volume = 0.31–0.70 ml) and relatively high flow rates (0.03–0.12 ml min−1) in studies of Zn(II) adsorption and retention in soils. Conservative tracer flow column experiments under saturation conditions were carried out to determine flow parameters for different flow rates. Column pore volume (Vp), Peclet numbers (Pe) and longitudinal dispersion coefficients (DL) were determined from breakthrough curves. The effect of type of electrolyte and ionic strength on the Zn(II) retention onto soil was determined. The influence of flow rate and bed height on the retention coefficient and on the mass transfer zone was also studied. The effect of different influent Zn(II) concentrations on the R values obtained was analyzed. Freundlich parameters from column experiments were compared with batch ones. The leaching efficiency of different electrolytes, salts of weak organic acids and EDTA was also studied. 相似文献
128.
依据JJF1059.1-2012,确立测量结果和不确定度评价的数学模型,从采集气样体积和采气后滤膜消解液待测物浓度和定容体积三个部分,A类不确定度和B类不确定度二个方面评定测量过程的不确定度,量化各不确定度分量。本次测量相对合成标准不确定度为0.024,较大的不确定度是样品浓度测量过程中的A类不确定度,主要由标准曲线测量和样品测量随机偏差引入,分量值分别为0.013和0.011。本次测量结果为0.169±0.008mg/m3(包含区间在0.161~0.177mg/m3),k=2。即在包含概率约为95%的条件下,可以判定该工作场所空气中硒化氢的含量已经超过了PC-TWA标准限值。 相似文献
129.
130.