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   171篇
  免费   1篇
  国内免费   4篇
安全科学   6篇
废物处理   14篇
环保管理   24篇
综合类   11篇
基础理论   24篇
污染及防治   59篇
评价与监测   26篇
社会与环境   11篇
灾害及防治   1篇
  2023年   4篇
  2022年   16篇
  2021年   9篇
  2020年   2篇
  2019年   4篇
  2018年   7篇
  2017年   6篇
  2016年   8篇
  2015年   5篇
  2014年   7篇
  2013年   19篇
  2012年   6篇
  2011年   9篇
  2010年   7篇
  2009年   10篇
  2008年   14篇
  2007年   5篇
  2006年   6篇
  2005年   2篇
  2004年   4篇
  2003年   2篇
  2002年   4篇
  1992年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   1篇
  1986年   1篇
  1985年   1篇
  1984年   1篇
  1980年   1篇
  1978年   1篇
  1975年   4篇
  1974年   2篇
  1973年   1篇
  1966年   1篇
排序方式: 共有176条查询结果,搜索用时 15 毫秒
41.
This study was carried out in order to determine some quality traits such as thousand grain weight (TGW), hectoliter weight (HW), grain protein content (GPC), Zeleny sedimentation volume (ZSV) and stability of quality traits of 25 bread wheat genotypes. The experiment was conducted at seven environmental conditions during 2 growing periods (2003-2004 and 2004-2005) using randomized complete block design with four replicates. The ANOVA showed that out of the total sum of squares, 48.4, 28.0 and 23.6% for TGW, 71.4, 14.9 and 13.7% for HW, 54.4, 23.0 and 22.6% for GPC, 44.7, 41.7 and 13.6% for ZSV was attributable to E, G and G x E interaction effects, respectively. Thousand grain weight, hectoliter weight, grain protein content and Zeleny sedimentasyon volume of genotypes changed from 34.5 to 41.4 g, from 76.5 to 80.4 Kg, from 11.49 to 13.37% and from 22.1 to 46.0 ml, respectively. Seven stability parameters, covering a wide range of statistical approaches, were used so as to predict the genotypes. The study of genotypic stability showed that Bezostaya and advanced lines numbered 11 and 24 had high stability for quality traits and proved to be the best within the pool of the studied genotypes. Also, 8 and 17 numbered genotypes demonstrated high stability for TGW, HW, GPC and HW, GPC and ZSV, respectively.  相似文献   
42.
Adsorption characteristics of Cu and Ni on Irish peat moss   总被引:1,自引:0,他引:1  
Peat has been widely used as a low cost adsorbent to remove a variety of materials including organic compounds and heavy metals from water. Various functional groups in lignin allow such compounds to bind on active sites of peat. The adsorption of Cu(2+) and Ni(2+) from aqueous solutions on Irish peat moss was studied both as a pure ion and from their binary mixtures under both equilibrium and dynamic conditions in the concentration range of 5-100mg/L. The pH of the solutions containing either Cu(2+) or Ni(2+) was varied over a range of 2-8. The adsorption of Cu(2+) and Ni(+2) on peat was found to be pH dependent. The adsorption data could be fitted to a two-site Langmuir adsorption isotherm and the maximum adsorption capacity of peat was determined to be 17.6 mg/g for Cu(2+) and 14.5mg/g for Ni(2+) at 298 K when the initial concentration for both Cu(2+) and Ni(2+) was 100mg/L, and the pH of the solution was 4.0 and 4.5, respectively. Column studies were conducted to generate breakthrough data for both pure component and binary mixtures of copper and nickel. Desorption experiments showed that 2mM EDTA solution could be used to remove all of the adsorbed copper and nickel from the bed.  相似文献   
43.
44.
The effects of mercuric chloride (HgCl2) on lipid profiles and lipid peroxidation in different body organs of fresh water cat-fish Heteropneustes fossilis were studied. The daily exposure of HgCl2 0.2 mg/L for 10, 20 and 30 days depleted the total lipids in brain. But the content of phospholipids enhanced significantly at 30 days. Significant diminution in C/P ratio was discernible with 30 days of exposure following mercury toxicosis. Liver exhibited elevated levels of total lipids, phospholipids, cholesterol and C/P ratio. Interestingly kidney showed marked decrease in the concentration of total lipids, cholesterol and C/P ratio at higher exposure. However, the phospholipid values increased during the longer exposure. The content of total lipids and phospholipids was high in muscle but the level of cholesterol and C/P ratio were depleted. Significant increment in lipid peroxidation was discernible in brain, liver and muscle. In kidney the rate of lipid peroxidation was significantly reduced. The results suggest that exposure of HgCl2 enhances the peroxidation of endogenous lipids in brain, liver and muscle. Interestingly the lipid contents are affected differently in different body organs.  相似文献   
45.
46.
The ability of Turkish illitic clay (TIC) in removal of Cd(II) and Pb(II) ions from aqueous solutions has been examined in a batch adsorption process with respect to several experimental conditions including initial solution pH, contact time, initial metal ions concentration, temperature, ionic strength, and TIC concentration, etc. The characterization of TIC was performed by using FTIR, XRD and XRF techniques. The maximum uptake of Cd(II) (11.25 mg g−1) and Pb(II) (238.98 mg g−1) was observed when used 1.0 g L−1 of TIC suspension, 50 mg L−1 of initial Cd(II) and 250 mg L−1 of initial Pb(II) concentration at initial pH 4.0 and contact time of 240 min at room temperature. The experimental data were analyzed by the Langmuir, Freundlich, Temkin and Dubinin Radushkevich (D-R) isotherm models. The monolayer adsorption capacity of TIC was found to be 13.09 mg g−1 and 53.76 mg g−1 for Cd(II) and Pb(II) ions, respectively. The kinetics of the adsorption was tested using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models. The results showed that the adsorption of Cd(II) and Pb(II) ions onto TIC proceeds according to the pseudo-second-order model. Thermodynamic parameters including the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes indicated that the present adsorption process was feasible, spontaneous and endothermic in the temperature range of 5–40 °C.  相似文献   
47.
Hasan SA  Hayat S  Ahmad A 《Chemosphere》2011,84(10):1446-1451
The present study was conducted with an aim to gain better insight of brassinosteroid generated response on the effects of cadmium on photosynthetic machinery and active oxygen metabolism in two tomato cultivars (K-25 and Sarvodya). These tomato cultivars were subjected to graded cadmium levels in soil (0, 3, 6, 9 or 12 mg kg−1 soil) with their foliage being sprayed with 0 or 10−8 M of 28-homobrassinolide/24-epibrassinolide (HBL/EBL) at 59 d stage. The results suggested that photosynthetic parameters, leaf water potential and activity of several enzymes (nitrate reductase and carbonic anhydrase) decreased significantly in both the cultivars, to a lesser extent in K-25 than Sarvodya with the increasing levels of cadmium in the soil. However, the activity of antioxidant enzymes and proline content increased in response to metal treatment as well as the application of brassinosteroids (HBL/EBL). Overall, exogenous application of brassinosteroids improved the activity of photosynthetic machinery and that of antioxidant defense system in both the cultivars, and also nullified the damaging effect of metal on these parameters.  相似文献   
48.
The increasing use of ozone in water disinfection processes has been the focus of considerable concern in regards to inorganic disinfection by product formation of bromate in waters containing bromide. Due to the public health risk caused by the presence of bromate as a suspected carcinogen, attention had been addressed to the conditions under which bromate is formed. In this study, photoanodic bromine generation and bromate (BrO(3)(-)) formation were investigated using a TiO(2) electrode in a photoelectrocatalytic (PEC) treatment process. The separation of anodic and cathodic reactions in the PEC system resulted in a pH decrease from 9.3 to 3.0 in the photoanode compartment and an increase to 11.0 in the cathode compartment. Under a photo-illumination intensity of 5.7 m W cm(-2) UV, a biasing potential of +1.0V vs SCE, a pH of 6.0 and at a NaBr concentration of 1.0 x 10(-2) M, active bromine formation increased over time with 2.4 x 10(-6) M min(-6) rate and reached a steady-state concentration of 1.44 x 10(-4) M in 60 min. Bromate formation was detected after a lag-period of 15 min and exhibited a continuous increasing trend with respect to irradiation time. No bromate formation was observed below pH 6.5 whereas an increasing bromate concentrations and pH up to pH=8.5 were noted.  相似文献   
49.
The aim of this study was to determine the origin and quality of waters in Troia. For this purpose total of 25 water samples including 2 springs, 14 surfaces and 9 groundwaters, were collected at eight different times. Global positioning system (GPS) was used to determine to coordinates of sampling points. The concentration of 6 minor elements (B, Cu, F, Fe, Pb and Zn), 9 major anions and cations (Na(+), Ca(2+), K(+), Mg(2+), SO(4)(2-), PO(4)(3-), HCO(3)(-), Cl(-) and, CO(3)(2-)) were determined by spectrometric, colorimetric and volumetric methods. Water pH, EC, DO, ORP and TDS were measured in situ using probes. The data showed that the concentrations of most of minor elements were below the EPA and TSE limits except Pb which ranged between 0.001 and 4.832 mg L(-1). Statistically significant relationships (P<0.01 and r>0.70) were observed between Fe and Cu, Cu and K(+), Cu and Ca(2+), B and Na(+), Na(+) and K(+). Assessing the water based on irrigation using Wilcox model showed that some well waters were not suitable for irrigation. Troia water was found to be highly corrosive and the average corrosion coefficients varied from 0.5 to 4.6. According to the Piper and Schoeller diagrams results, the water in Troia was classified as mixed water type.  相似文献   
50.
The distribution of Nickel-63, Iron-59, Manganese-54 and Tin-113 in plasma was studied in rats which received single intravenous (i.v.) injection of aqueous solutions of their salts alone, and in rats which also received single intramuscular (im) injection of triethylene tetramine (TETA). TETA was extremely effective in reducing the plasma concentration of Nickel-63 followed by that of Iron-59, Manganese-54 and Tin-113.  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