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   5587篇
  免费   13篇
  国内免费   90篇
安全科学   118篇
废物处理   277篇
环保管理   543篇
综合类   683篇
基础理论   2073篇
环境理论   1篇
污染及防治   1220篇
评价与监测   415篇
社会与环境   349篇
灾害及防治   11篇
  2023年   27篇
  2022年   110篇
  2021年   78篇
  2020年   25篇
  2019年   42篇
  2018年   201篇
  2017年   176篇
  2016年   266篇
  2015年   129篇
  2014年   80篇
  2013年   216篇
  2012年   499篇
  2011年   317篇
  2010年   126篇
  2009年   127篇
  2008年   137篇
  2007年   138篇
  2006年   123篇
  2005年   636篇
  2004年   843篇
  2003年   659篇
  2002年   92篇
  2001年   152篇
  2000年   62篇
  1999年   59篇
  1998年   21篇
  1997年   23篇
  1996年   12篇
  1995年   31篇
  1994年   11篇
  1993年   11篇
  1992年   18篇
  1991年   18篇
  1990年   17篇
  1989年   16篇
  1988年   7篇
  1987年   8篇
  1985年   11篇
  1984年   10篇
  1983年   8篇
  1982年   8篇
  1981年   7篇
  1980年   8篇
  1979年   7篇
  1975年   11篇
  1974年   12篇
  1973年   8篇
  1972年   15篇
  1966年   7篇
  1957年   6篇
排序方式: 共有5690条查询结果,搜索用时 156 毫秒
1.
Environmental Science and Pollution Research - The present research article uses simultaneous equation modelling approach to investigate the three-way linkages between economic growth, energy...  相似文献   
2.
Environmental Science and Pollution Research - Buildings account for nearly 2/5ths of global energy expenditure. Due to this figure, the 90s witnessed the rise of green buildings (GBs) that were...  相似文献   
3.
The chemical recycling of cellulosic fibres may represent a next-generation fibre–fibre recycling system for cotton textiles, though remaining challenges include how to accommodate fibre blends, dyes, wrinkle-free finishes, and other impurities from finishing. These challenges may disrupt the regeneration process steps and reduce the fibre quality. This study examines the impact on regenerated viscose fibre properties of a novel alkaline/acid bleaching sequence to strip reactive dyes and dimethyloldihydroxyethyleneureas (DMDHEU) wrinkle-free finish from cotton textiles. Potentially, such a bleaching sequence could advantageously be integrated into the viscose process, reducing the costs and environmental impact of the product. The study investigates the spinning performance and mechanical properties (e.g., tenacity and elongation) of the regenerated viscose fibres. The alkaline/acid bleaching sequence was found to strip the reactive dye and DMDHEU wrinkle-free finish from the cotton fabric, so the resulting pulp could successfully be spun into viscose fibres, though the mechanical properties of these fibres were worse than those of commercial viscose fibres. This study finds that reactive dyes and DMDHEU wrinkle-free finish affect the viscose dope quality and the regeneration performance. The results might lead to progress in overcoming quality challenges in cellulosic chemical recycling.  相似文献   
4.
Environmental Chemistry Letters - Water desalination and recycling of wastewater is a key challenge to meet water shortage issues. Thin film composite polyamide membranes are widely used for...  相似文献   
5.
6.
7.
Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder.  相似文献   
8.
Air pollution has emerged as an imminent issue in modernsociety. Prediction of pollutant levels is an importantresearch topic in atmospheric environment today. For fulfillingsuch prediction, the use of neural network (NN), and inparticular the multi-layer perceptrons, has presented to be acost-effective technique superior to traditional statisticalmethods. But their training, usually with back-propagation (BP)algorithm or other gradient algorithms, is often with certaindrawbacks, such as: 1) very slow convergence, and 2) easilygetting stuck in a local minimum. In this paper, a newlydeveloped method, particle swarm optimization (PSO) model, isadopted to train perceptrons, to predict pollutant levels, andas a result, a PSO-based neural network approach is presented. The approach is demonstrated to be feasible and effective bypredicting some real air-quality problems.  相似文献   
9.
In this paper we apply graph theory in a reserve selection exercise to explore the tradeoffs between maintaining connectivity and minimizing the total area of a protected area network. Rather than focus on a single organism, we used a multi-species approach and looked at the tradeoff curves for organisms with varying dispersal abilities. We first generated the tradeoff curves using a graph-based metric to determine the importance of individual patches for maintaining connectivity. We then performed an analogous set of analyses using patch size as a surrogate measure of importance.  相似文献   
10.
The reduction of SO2 by the addition of ammonia gas has been studied in a 2 m high fluidized bed combustor having a 30 cm static bed height and a freeboard height of 170 cm. Ammonia gas was injected at 52 cm above the distributor where the temperature is ca. 700° C by an uncooled stainless steel tube injector. Experiments were carried out to investigate the effects of amminia gas injection on sulphur dioxide emissions at unstaged conditions of: (i) excess air level, (ii) NH3:SO2 molar ratio, (iii) fluidizing velocity and (iv) bed height.A maximum reduction of 75% in SO2 emissions was found at 40% excess air, at an NH3:SO2 molar ratio of 5.4. The onset of SO2 reduction occurred at an NH3:SO2 ratio of 1.5 However, the most effective ratio was found to be between 3 and 5. Fluidizing velocity and bed height were also found to have significant influence on SO2 reduction.It is difficult to determine how the SO2 reduction varied with operating conditions. When ammonia is added in the main combustor zone, the temperature is much higher than that required for the occurrence of sulphur dioxide-ammonia and sulphur trioxide-ammonia reactions. However, this paper points out the significance of ammonia addition in the reduction of sulphur dioxide.  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