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   932篇
  免费   11篇
安全科学   20篇
废物处理   61篇
环保管理   57篇
综合类   172篇
基础理论   155篇
污染及防治   309篇
评价与监测   108篇
社会与环境   55篇
灾害及防治   6篇
  2023年   12篇
  2022年   30篇
  2021年   35篇
  2020年   15篇
  2019年   17篇
  2018年   49篇
  2017年   29篇
  2016年   60篇
  2015年   43篇
  2014年   51篇
  2013年   72篇
  2012年   35篇
  2011年   62篇
  2010年   51篇
  2009年   27篇
  2008年   65篇
  2007年   53篇
  2006年   43篇
  2005年   27篇
  2004年   27篇
  2003年   29篇
  2002年   23篇
  2001年   20篇
  2000年   12篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1996年   4篇
  1995年   6篇
  1994年   9篇
  1993年   5篇
  1992年   5篇
  1991年   1篇
  1990年   3篇
  1988年   1篇
  1986年   1篇
  1985年   2篇
  1984年   2篇
  1983年   1篇
  1982年   2篇
  1981年   2篇
  1979年   1篇
  1978年   1篇
  1975年   2篇
  1964年   1篇
  1962年   1篇
排序方式: 共有943条查询结果,搜索用时 93 毫秒
861.
The aim of this study is to evaluate extensively the characterization and identification of major pollutant parameters by paying attention to the organic chemical pollution for unregulated dumping site leachate in Eskişehir/Turkey. The study that is first and only one research has been very important data related with before new sanitary landfill site in Eskişehir city. For this purpose, in this study leachate samples were collected in-situ at monthly interval for a period of 8 months. Firstly, thirty three physicochemical parameters were monitored. Secondly, SPME technique was used for identification of organic pollutants. Meteorological data were also recorded for the same sampling period to correlate meteorological data and physicochemical parameters. Mean values are used in the correlation analysis. Correlation is shown only for the relationship between air temperature and NO3 . No correlation has been found between rain and leachate quality parameters since the amount of rain was very low during the sampling period. However, analysis results were generally decreased in winter season when each parameter and each sampling point are examined separately. According to correlation between every parameter, especially solid content and dissolved oxygen concentration of leachate is affecting to other parameters. Also, sodium and potassium are changing proportionally with same parameters (suspended solids, fixed solids, dissolved oxygen) and high correlation between chloride and heavy metal concentration is showing. The results were statistically evaluated by use of SPSS 10.0 program. Second part of the study, the leachate was extracted by Solid Phase Microextraction (SPME) technique and then analyzed. Of the methodologies tested in this study, the best one selected was based on 100 μ m polydimethylsiloxane coated fiber (PDMS), headspace with heating (Δ HS) sampling mode and an extraction time of 15 min. at a temperature of 50 o C. Thirty three organic compounds in leachate were identified by GC/MS.  相似文献   
862.
Lake Vela, located in the Portuguese littoral-centre, is a temperate shallow lake exhibiting a high trophic status. This aquatic ecosystem has been potentially exposed to contamination generated by agricultural and livestock activities held in their drainage basin, which seriously compromise their health. This work summarizes some background information and presents the problem formulation step of the ERA. Therefore, it evaluates the characteristics of the stressor(s), describes the ecological system and receptors and suggests a conceptual model, which predicts the potential exposure pathways, relating suspected sources to the defined endpoints. This introductory step also described an analysis plan on the entire study, which includes a delineation of the assessment design, data needs, measures, and methods for conducting the analysis phase of the risk assessment process.  相似文献   
863.
A new test method is described for assessing biodegradation of plastic material under simulated soil conditions. An inert substrate can be activated with soil extract and nutrient and used in place of soil in biodegradation tests. The biodegradation level is evaluated by determining the carbon dioxide (CO2) production released by the test reactors. Effects of substrate nature, solution pH, nutrient composition, soil extract concentration, and activation duration on CO2 production were investigated, and the experimental conditions were optimized. Results obtained with cellulose showed a biodegradation rate of 80% within 28 days. Moreover, with this kind of substrate, reaction products and residues can be easily extracted and analysed.  相似文献   
864.
865.
866.
867.
Ultrasonography in a female fetus revealed cystic cervical hygroma, severe micrognathia, and vertebral and upper limb anomalies suggestive of cerebro-costo-mandibular syndrome (CCMS) which was diagnosed ultrasonographically at 16 weeks' gestation. The father is affected and presents with a Pierre Robin sequence, short stature and typical costovertebral anomalies. CCMS is a rare and severe disorder. The high frequency of sporadic cases, vertical transmission, and the excess of sibs affected via horizontal transmission suggest dominant autosomal mutation with possible germinal mosaicism. The vertical familial case detailed in the present report is a reminder of the high risk when one parent or one sibling is affected and the extreme variability of phenotype and costal ossification. Early prenatal ultrasound diagnosis is possible in a severely affected fetus. Copyright © 2001 John Wiley & Sons, Ltd.  相似文献   
868.
869.
Inorganic chemical composition of native trees of the Atlantic Forest   总被引:1,自引:0,他引:1  
The Atlantic Forest with its exuberant vegetation of high level of biodiversity is classified as one hotspot of the world. Chemical composition of leaves from native trees and underlying soils was evaluated by INAA. The predominant species Euterpe edulis, Bathysa meridionalis, Hyeronima alchorneoides, Marlierea tomentosa, Gomidesia flagellaris, and Gomidesia spectabilis belonging to the diverse plant families were studied. Euterpe edulis, the most abundant understory specie, presented the lowest element concentrations except for Zn. Some variation in chemical composition was noted, however, the chemical specificity of tree species can be more predominant than the soil variability for the obtained leaf concentrations. Factor values obtained through the Monte-Carlo assisted factor analysis were used for species discrimination. The results indicate that chemical investigation of native trees is a quite promising tool for biodiversity studies in the Atlantic Forest.  相似文献   
870.
We describe a method for the simultaneous determination of eight kinds of phenylbenzotriazole-type mutagens (PBTA-1, -2, -3, -4, -5, -6, -7 and -8) in river water based on liquid chromatography-tandem mass spectrometry (LC/MS/MS). The application of dopant-assisted atmospheric pressure photoionization (APPI) for the detection of the PBTAs was studied. The APPI technique provided higher PBTA signal intensities than those obtained with an electrospray ionization (ESI) source, and the APPI method was used for the determination of the PBTAs. A solid-phase extraction procedure was used for the extractions of PBTA-1 through -8 from river water. The procedure was rapid and the relative standard deviations were below 15%. The detection limits of PBTA-1 through -8 in river water using the proposed method were found to range from 0.04 to 0.5 ng L(-1) and PBTAs were successfully detected in river water at sub-ng L(-1) levels.  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