全文获取类型
收费全文 | 494篇 |
免费 | 47篇 |
国内免费 | 99篇 |
专业分类
安全科学 | 76篇 |
废物处理 | 37篇 |
环保管理 | 73篇 |
综合类 | 288篇 |
基础理论 | 37篇 |
污染及防治 | 79篇 |
评价与监测 | 17篇 |
社会与环境 | 22篇 |
灾害及防治 | 11篇 |
出版年
2024年 | 1篇 |
2023年 | 4篇 |
2022年 | 23篇 |
2021年 | 21篇 |
2020年 | 22篇 |
2019年 | 12篇 |
2018年 | 16篇 |
2017年 | 20篇 |
2016年 | 16篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 26篇 |
2012年 | 40篇 |
2011年 | 44篇 |
2010年 | 29篇 |
2009年 | 20篇 |
2008年 | 20篇 |
2007年 | 44篇 |
2006年 | 47篇 |
2005年 | 29篇 |
2004年 | 19篇 |
2003年 | 24篇 |
2002年 | 16篇 |
2001年 | 10篇 |
2000年 | 13篇 |
1999年 | 7篇 |
1998年 | 10篇 |
1997年 | 12篇 |
1996年 | 7篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 4篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1980年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有640条查询结果,搜索用时 15 毫秒
161.
162.
163.
针对国内硫磺回收装置实际生产中存在的设备腐蚀问题,根据不同的腐蚀机理进行了腐蚀分类,分析了腐蚀原因并提出了具体的防护措施. 相似文献
164.
The study on population and the resource-environment by the consumption may contribute to the further cognition about their correlations and provide the policy references for natural resources use and environmental protection. This article has studied the impact status of the consumption level difference of China's 31 provinces or autonomous regions on the resource-environment in 2005 by per capita consumption expenditure and serial statistical data with unit person method and constructed consumption model and hierarchical cluster analysis. We found several trends. To the intensity that population acting on the resource-environment, four sorts of regions might be divided in 2005, furthermore, most of them were at the level of unit person. Provinces or autonomous regions, located in the developed coastal areas in China, generally have the bigger impact intensity on the resource-environment than the others. That is to say, the natural resources mainly flow from west to east and from north to south, but the environmental loads are shared in the whole China and are likely to be aggravated from east to west reversely. The main causes of imbalance of pressure on the resource-environment should be the difference of consumption level, the unmatchable resource exploitation and utilization, the imbalance of discharging pollutants, and the difference of moderate carrying capacity. To the total impact quantities that population acting on the resource-environment, four sorts of regions were divided in 2005 and the difference of them was notable. Provinces or autonomous regions, having the bigger impact quantities on the resource-environment, are generally located in the eastern and central China while the extended western China is still the weak impact area of the resource-environment consumption or terminal pressure. Provinces or autonomous regions are few, where the total impact quantities are more or less; alternately, those are many, where the total impact quantities rank the middle. 相似文献
165.
复合垂直流人工湿地氧化还原特征及不同功能区净化作用研究 总被引:1,自引:0,他引:1
研究了复合垂直流人工湿地系统氧化还原电位(Eh)的时空变化规律及不同功能区中污染物的净化效果。结果表明:湿地系统下行流池表层、两池底层、上行流池表层Eh的变化范围分别为402~585、-87~-130、308~432 mV,沿水流方向依次形成了好氧A区/缺氧、厌氧区/好氧B区3个功能区。好氧A区是污染物去除的主要区域,BOD5、CODCr、NH+4- N的去除率分别为430%、484%、541%,特别是NH+4 N去除率占总去除率的79%;缺氧、厌氧区主要是进行反硝化反应和有机物的厌氧分解;好氧B区则主要是去除厌氧分解后的有机物以及进一步脱氮。另外,NH+4 N的去除率与系统各功能区Eh呈显著相关关系(〖WTBX〗p〖WTBZ〗<001),而BOD5、CODCr、NO-3-N的去除率与系统各功能区Eh相关性不显著。 相似文献
166.
Energy-Saving Effect Calculation and Implementation Strategy Study on the Industrial Structure Adjustment in Western China 总被引:1,自引:0,他引:1
The western region is an important strategic base of energy in China. The average per capita possession of fossil energy in the west is twice that in China. On the basis of the analysis of the mechanism how industrial structure adjustment affects energy consumption per unit of gross domestic product (GDP), the energy input-output table of western China was designed and compiled. Combining multiobjective planning techniques, setting energy-saving, economic growth, and laborer's income growth as the goals, setting basic input-output relations, production capacity, and labor as the constraints, the multiobjective optimization model of western energy input-output was constructed. The results of industrial structure optimization of western China show that: with technology and product price remaining unchanged, the adjustment of the industrial structure can reduce energy consumption per unit GDP by 2.7%, at the same time ensuring the average annual increase of GDP and laborer's income of western region in excess of 8%. It indicates that industrial structure adjustment is an effective method in accomplishing the aim of energy saving. Finally, policy suggestions from four angles, such as industrial chain and financial policies, were put forward. 相似文献
167.
Mu Hao Wang Marvin L. Granstrom Thomas E. Wilson Lawrence K. Wang 《Journal of the American Water Resources Association》1974,10(2):283-294
ABSTRACT: Ion flotation is the term used to describe a process in which there is an initally homogeneous solution which becomes heterogeneous after the addition of an oppositely charged surfactant due to the reaction between the surfactant and specific ion(s); thus, insoluble complexes are formed. These insoluble complexes will then attached to the bubbles passing through the solution and thus leave in the foam phase. The performance of the continuous ion flotation process for the removal of haft lignin from water was investigated intensively using liquid flow rates, gas flow rates, feed locations and solution height as operational variables. The interrelationships among these physical parameters were studied and discussed. A dimensionless operational chart was established for process control. Results demonstrate that ion flotation is an effective process for removing lignin from water, provided that a quaternary ammonium salt, such as cetyldimethylbenzyl-ammonium chloride or the like, is used as a collector. At optimum operational conditions, higher than 0.95 fractional removal of lignin can be achieved. 相似文献
168.
169.
170.