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   354篇
  免费   2篇
  国内免费   6篇
安全科学   9篇
废物处理   44篇
环保管理   36篇
综合类   29篇
基础理论   46篇
环境理论   1篇
污染及防治   144篇
评价与监测   38篇
社会与环境   13篇
灾害及防治   2篇
  2023年   11篇
  2022年   35篇
  2021年   27篇
  2020年   14篇
  2019年   15篇
  2018年   17篇
  2017年   14篇
  2016年   19篇
  2015年   13篇
  2014年   18篇
  2013年   49篇
  2012年   16篇
  2011年   13篇
  2010年   7篇
  2009年   9篇
  2008年   7篇
  2007年   8篇
  2006年   8篇
  2005年   10篇
  2004年   6篇
  2003年   7篇
  2002年   6篇
  2001年   2篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1995年   1篇
  1994年   3篇
  1993年   1篇
  1991年   1篇
  1990年   2篇
  1989年   1篇
  1988年   2篇
  1987年   1篇
  1984年   1篇
  1982年   1篇
  1980年   2篇
  1978年   1篇
  1977年   1篇
  1972年   1篇
  1966年   1篇
  1965年   1篇
  1964年   2篇
排序方式: 共有362条查询结果,搜索用时 343 毫秒
11.
Environmental Science and Pollution Research - Drug resistance of cancer cells is a major issue in cancer treatment. Plant-mediated nanoparticle synthesis has been applied in recent years to...  相似文献   
12.
This study aims to determine the difference of serum Pb and Hg levels in adolescents with or without metabolic syndrome (MetS) and the association of serum levels of these heavy metals with cardiometabolic risk factors and liver enzymes in Iranian adolescents. The study population consisted of 320 adolescents (160 with MetS and 160 healthy controls). The relationship between serum heavy metals and cardiometabolic risk factors was assessed by linear regression. The odds ratios (OR) of having metabolic syndrome across Pb and Hg quartiles were determined by multiple logistic regression analysis. The mean (SD) of Pb and Hg concentrations were higher in adolescents with MetS than in those without it (0.83 (0.27) and 0.17 (0.01) vs. 0.65 (0.15) and 0.10 (0.08)?μg/L, P?=?0.01 and 0.0001, respectively). Increase in serum Pb and Hg was associated with increase in some cardiometabolic risk factors. Among boys and girls, diastolic blood pressure (DBP), fasting blood glucose, total cholesterol (TC), triglycerides (TG), and alanine aminotransaminase increased significantly across quartiles of serum Pb. Among girls, SBP, DBP, TC, and TG had a significant increase across Hg quartiles. The corresponding figure among boys was significant for SBP, DBP, and TG. Higher quartiles of Pb increased the risk of having MetS (OR 95 % CI 3.10, 2.25–4.27), the corresponding figure was 2.03, 1.75–3.16, across Hg quartiles. Our study showed significant associations between serum Pb and Hg levels with cardiometabolic risk factors in adolescents. In future surveys, the role of potential confounders should be considered more extensively. The clinical significance of these findings needs to be confirmed in longitudinal studies. By considering the origins of chronic diseases from early life, controlling environmental pollutants should be considered as a health priority for primordial or primary prevention of noncommunicable diseases.  相似文献   
13.
ABSTRACT

This article aims to study the influence of the addition of graphene oxide nanoparticles (GO) to diesel/higher alcohols blends on the combustion, emission, and exergy parameters of a CI engine under various engine loads. The higher alcohols mainly n-butanol, n-heptanol, and n-octanol are blended with diesel at a volume fraction of 50%. Then, the 25 and 50 mg/L concentrations of GO are dispersed into diesel/higher alcohols blends using an ultrasonicator. The GO structures are examined using TEM, TGA, XRD and FTIR. The findings show that there is a reduction in pmax. and HRR when adding higher alcohols with diesel fuel. Regarding engine emission, there is a significant improvement in emissions formation with adding higher alcohols. The addition of GO into diesel/higher alcohols blends improves the brake thermal efficiency by 15%. Moreover, the pmax. and HRR are both enhanced by 4%. The CO, UHC and smoke formation are reduced considerably by 40%, 50 and 20%, respectively, while NOx level is increased by 30% with adding GO. Finally, adding high percentages of n-butanol, n-heptanol, and n-octanol with diesel fuel with the presence of GO has the potential to achieve ultra-low CO, UHC, and smoke formation meanwhile keeping high thermal efficiency level.  相似文献   
14.
The use of assimilation tools for satellite validation requires true estimates of the accuracy of the reference data. Since its inception, the Network for Detection of Stratospheric Change (NDSC) has provided systematic lidar measurements of ozone and temperature at several places around the world that are well adapted for satellite validations. Regular exercises have been organised to ensure the data quality at each individual site. These exercises can be separated into three categories: large scale intercomparisons using multiple instruments, including a mobile lidar; using satellite observations as a geographic transfer standards to compare measurements at different sites; and comparative investigations of the analysis software. NDSC is a research network, so each system has its own history, design, and analysis, and has participated differently in validation campaigns. There are still some technological differences that may explain different accuracies. However, the comparison campaigns performed over the last decade have always proved to be very helpful in improving the measurements. To date, more efforts have been devoted to characterising ozone measurements than to temperature observations. The synthesis of the published works shows that the network can potentially be considered as homogeneous within +/-2% between 20-35 km for ozone and +/-1 K between 35-60 km for temperature. Outside this altitude range, larger biases are reported and more efforts are required. In the lower stratosphere, Raman channels seem to improve comparisons but such capabilities were not systematically compared. At the top of the profiles, more investigations on analysis methodologies are still probably needed. SAGE II and GOMOS appear to be excellent tools for future ozone lidar validations but need to be better coordinated and take more advantage of assimilation tools. Also, temperature validations face major difficulties caused by atmospheric tides and therefore require intercomparisons with the mobile systems, at all sites.  相似文献   
15.
This paper presents a forecasting study of municipal solid waste generation (MSWG) rate and potential of its recyclable components in Kuala Lumpur (KL), the capital city of Malaysia. The generation rates and composition of solid wastes of various classes such as street cleansing, landscape and garden, industrial and constructional, institutional, residential and commercial are analyzed. The past and present trends are studied and extrapolated for the coming years using Microsoft office 2003 Excel spreadsheet assuming a linear behavior. The study shows that increased solid waste generation of KL is alarming. For instance, the amount of daily residential SWG is found to be about 1.62 kg/capita; with the national average at 0.8–0.9 kg/capita and is expected to be increasing linearly, reaching to 2.23 kg/capita by 2024. This figure seems reasonable for an urban developing area like KL city. It is also found that, food (organic) waste is the major recyclable component followed by mix paper and mix plastics. Along with estimated population growth and their business activities, it has been observed that the city is still lacking in terms of efficient waste treatment technology, sufficient fund, public awareness, maintaining the established norms of industrial waste treatment etc. Hence it is recommended that the concerned authority (DBKL) shall view this issue seriously.  相似文献   
16.
17.
18.
19.
The effect of Dimethoate, Carbaryl and Permethrin on the activities of liver L-tryptophan 2,3-dioxygenase (total-, holo-, and apo-forms) and pyridoxal phosphokinase of male mice was investigated. Dimethoate inhibited both enzyme systems after single and repeated dose treatment; except the dioxygenase holo-enzyme after repeated doses. Single dose of Carbaryl treatment inhibited the pyridoxal phosphokinase, total and holo-enzyme of L-tryptophan dioxygenase. However, the repeated dose treatment do not affect both enzyme systems. Permethrin inhibited only total-, holo- and apo-enzymes of L-tryptophan dioxygenase whereas repeated administration has no significant effect on both enzymes. The data indicate that these insecticides may induce abnormal tryptophan metabolism through which some endogenous bladder carcinogens are formed.  相似文献   
20.
Sayed M. Hassan 《Chemosphere》1994,29(12):2555-2569
A single column ion chromatographic method for the determination of sulfide, sulfite, sulfate and thiosulfate was developed. It uses an anion exchange column (Waters, IC-Pak A) and a borate-gluconate buffer at pH 8.5 that contains EDTA and ascorbic acid to prevent sulfite oxidation. This eluent has relatively low background values for both conductivity and ultraviolet absorption, which allows determination of the above sulfur anions with high sensitivity. The mean percent recovery of the investigated anions in synthetic mixtures were 98.6, 100.0, 99.6 and 100.2 % for sulfide, sulfite, thiosulfate and sulfate, respectively. The method was applied to study sulfide ion oxidation at the water-sediment interface using six aquifer samples collected within the continental United States. Results indicated that sulfide ion disappearance follows a pseudo first-order profile and that the rate of disappearance correlates with the total organic carbon and clay content of the sediment.  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