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   91篇
  免费   0篇
废物处理   4篇
环保管理   2篇
综合类   7篇
基础理论   33篇
污染及防治   40篇
评价与监测   3篇
灾害及防治   2篇
  2022年   1篇
  2017年   1篇
  2014年   3篇
  2013年   6篇
  2012年   7篇
  2011年   4篇
  2010年   1篇
  2009年   1篇
  2008年   5篇
  2007年   3篇
  2006年   1篇
  2005年   6篇
  2003年   2篇
  2002年   5篇
  2001年   3篇
  2000年   5篇
  1999年   4篇
  1998年   4篇
  1997年   6篇
  1996年   2篇
  1995年   8篇
  1994年   5篇
  1992年   1篇
  1991年   2篇
  1986年   2篇
  1984年   1篇
  1976年   1篇
  1954年   1篇
排序方式: 共有91条查询结果,搜索用时 0 毫秒
11.
Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, Meriones persicus, Meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P < 0.01). The total numbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P < 0.01), while the numbers of white blood cells showed no significant difference.  相似文献   
12.
ABSTRACT: Nutrient data from all available sources for the lower Mississippi River were examined for potential differences among sampling agencies and geographic locations for the period between 1960 and 1998. Monthly means grouped by parameter, sampling location and agency, were calculated and compared as paired sets, excluding those months where data were not available for both sets. Some significant differences were found between various agencies collecting nutrient data on the river, as well as between various stretches of river, especially in the case of phosphorus nutrient data. Results were used to synthesize data sets from which a history of nutrient loading in the Mississippi River was determined. General trends in nitrate+nitrite, total Kjeldahl nitrogen, orthophosphate, total phosphorus and silica loads, as well as changes in nutrient proportions and the specific limiting nutrient (by month) are reported. This study provides a useful summary of contemporary and historical nutrient data that may assist in the evaluation of Mississippi River water quality and its potential effect on the Gulf of Mexico.  相似文献   
13.
Conflict are frequently observed when drinking water protection areas are to be defined and when many variants of how to protect these area are to be found. Using ten potential scenarios, a method is presented here which shows how such conflicts concerning these variants may be handled in a systematic manner. The technique is derived from the use of partially ordered sets and their visualization by Hasse diagrams. The first step is to define rankings of different variants according to each aim of protection. A further step is to define an appropriate relationship of order. It is then possible to visualize the extent of consensus and of dissension through the use of a Hasse diagram. The final step is to quantify the importance of each protection aim and the initialization of an iteration. Should a complete consensus be found, this would result in a chain of (connected) variants. Should a complete dissension be found on the other hand, an antichain would then result (i.e. where all variants are isolated).  相似文献   
14.
The biofilter and the ionisation system are two oxidative treatment techniques for purification of waste gas streams with low concentrations of volatile organic compounds. In this paper, the authors present the investigations of an ionisation technique aimed at increasing the efficiency of the reduction of the odorant concentration in waste gas streams from biological waste treatment plants. The objective is to enable advanced odour emission reduction and to adjust the existing biofilters to stricter requirements. In a first step, the odorous substances which are major contributors to the overall odorant concentration are identified on basis of various emission data sets with the help of a method of life cycle impact assessment. Thereby limonene, alpha-pinene, ethyl butyrate and dimethyl disulphide were identified as crucial indicators. In a second step, experimental investigations using limonene as a model compound were conducted to gain an understanding of the ionisation process itself and at last for the evaluation of the system.  相似文献   
15.
Background, Aims and Scope The acidification of mine waters is generally caused by metal sulfide oxidation, related to mining activities. These waters are characterized by low pH and high acidity due to strong buffering systems. The standard acidity parameter, the Base Neutralization Capacity (BNC) is determined by endpoint titration, and reflects a cumulative parameter of both hydrogen ions and all buffering systems, but does not give information on the individual buffer systems. We demonstrate that a detailed interpretation of titration curves can provide information about the strength of the buffering systems. The buffering systems are of importance for environmental studies and treatment of acidic mining waters. Methods Titrations were carried out by means of an automatic titrator using acidic mining waters from Germany and Canada. The curves were interpreted, compared with each other, to endpoint titration results and to elemental concentrations contained therein. Results and Discussion The titration curves were highly reproducible, and contained information about the strength of the buffer systems present. Interpretations are given, and the classification and comparison of acidic mining waters, by the nature and strength of their buffering systems derived from titration curves are discussed. The BNC-values calculated from the curves were more precise than the ones determined by the standard endpoint titration method. Due to the complex buffer mechanisms in acidic mining waters, the calculation of major metal concentrations from the shape of the titration curve resulted in estimates, which should not be confused with precise elemental analysis results. Conclusion Titration curves provide an inexpensive, valuable and versatile tool, by which to obtain sophisticated information of the acidity in acidic water. The information about the strength of the present buffer systems can help to understand and document the complex nature of acidic mining water buffer systems. Finally, the interpretation of titration curves could help to improve treatment measurements and the ecological understanding of these acidic waters.  相似文献   
16.
17.
18.
The localisation of halogenated furanones, the biologically active secondary metabolites from the red alga Delisea pulchra (Greville), was determined by a combination of fluorescence microscopy, culture studies and quantitative chemical analyses. All types of evidence showed that furanones are localised in the central vesicle of gland cells in D. pulchra. These cells release furanones onto the surface of the plant, where they can be quantified using a newly developed surface extraction-technique. Levels of furanones on the surface of the plant were highest near the apical tips (≃100 ng cm−2), and decreased towards the base of the alga. Variation in furanone levels within the plant and variation in the number of gland cells followed a similar pattern. The localisation of furanones within gland cells in D. pulchra and the presence and concentrations of furanones on the surface of the plant are consistent with furanones functioning as antifoulants and in mediating other ecological interactions at the surface of the alga. Received: 5 March 1998 / Accepted: 10 September 1998  相似文献   
19.
An evaluation of the degradation of soils can be performed in several ways. Here, one way will be demonstrated beginning with the definition of the objects which are to be evaluated, continued with the definition of protection aims and the derivation of indicators. Objects together with indicators provide the frame within which a multicriteria assessment, has to be performed. Often no deterministic quality function is available, so that the concept of partially ordered sets is suggested. This concept is demonstrated by an example of an evaluation exercise performed for the environmental protection agency in Baden Württemberg. A result is that the use of arbitrarily defined quality functions may lead to erroneous statements.  相似文献   
20.
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