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   702篇
  免费   43篇
  国内免费   190篇
安全科学   31篇
废物处理   18篇
环保管理   131篇
综合类   337篇
基础理论   193篇
环境理论   1篇
污染及防治   119篇
评价与监测   51篇
社会与环境   53篇
灾害及防治   1篇
  2024年   2篇
  2023年   9篇
  2022年   19篇
  2021年   30篇
  2020年   22篇
  2019年   15篇
  2018年   23篇
  2017年   25篇
  2016年   30篇
  2015年   39篇
  2014年   41篇
  2013年   77篇
  2012年   44篇
  2011年   79篇
  2010年   55篇
  2009年   45篇
  2008年   31篇
  2007年   61篇
  2006年   57篇
  2005年   47篇
  2004年   21篇
  2003年   32篇
  2002年   12篇
  2001年   12篇
  2000年   16篇
  1999年   10篇
  1998年   15篇
  1997年   4篇
  1996年   8篇
  1995年   11篇
  1994年   7篇
  1993年   6篇
  1992年   7篇
  1991年   2篇
  1990年   2篇
  1987年   1篇
  1985年   1篇
  1984年   1篇
  1983年   1篇
  1982年   2篇
  1981年   1篇
  1979年   1篇
  1978年   2篇
  1976年   2篇
  1975年   1篇
  1973年   1篇
  1972年   1篇
  1971年   4篇
排序方式: 共有935条查询结果,搜索用时 15 毫秒
761.
胡永飘  简弃非 《环境科技》2005,18(3):27-28,32
在火电厂的电力生产过程中,噪声污染是主要的环境污染之一,噪声污染源分布很广,难以集中治理。为此对火电厂的噪声源进行分析,提出治理的主要技术措施,重点用火电厂水泵房的治理实例探讨治理技术的实际应用问题。  相似文献   
762.
The concentration and distribution of nonylphenol polyethoxylates (NPEOs represents the mixture, and NPnEO represents the monomer) and its metabolites in the influent and effluent of four municipal sewage treatment plants (STPs) in the north of China were measured. Moreover, the concentration and distribution of the above chemicals in the sludge of two STPs were also determined, and the transfer and fate of NPEOs in the sewage treatment process were discussed primarily by analyzing the distribution of the products in the effluent and the sludge. The results showed that NPEOs and its metabolites existed in all the samples of the influent, effluent, and sludge. NPEOs were degraded in the sewage treatment process with the removal efficiency in the range of 23.38%–77.11%, or an average of 52.86%. However, the large analogs of NPnEO were only degraded to small ones, whose degradation rate was rather slow, and consequently the degradation was not complete. Hence, the concentrations of some small metabolites, such as nonylphenol (NP), nonylphenol monoethoxylate (NP1EO), and nonylphenol diethoxylate (NP2EO) were elevated in the effluent. These small metabolites are more toxic than the large NPnEO analogs, and some of them were reported to exhibit environmental endocrine disrupting activity. From this point of view, the process of sewage treatment does not reduce but elevate the risk of NPEOs, which becomes the main source of these small NPnEO in the environment. The sludge exhibited good adsorption ability for NPEOs, especially for the small analogs, which led to the high level of NPEOs in the sludge. Hence, reasonable disposal of the surplus sludge to avoid re-pollution is very important. Translated from Research of Environmental Sciences, 2006, 19(3): 61–66 [译自: 环境科学研究]  相似文献   
763.
海河流域是我国农业发展的一个重要基地,由于不合理开发利用,造成某些地区土壤出现贫瘠化、盐渍化和沙漠化,土壤缺磷也很明显.为了寻找植物对磷的需求特点以及海河流域土壤磷分布规律,可以从植物指示的角度研究不同地区不同植物磷含量特征及其差异,研究植物每年从土壤中输出和输入的磷总量,从而寻找农业生态系统磷循环规律并科学指导施肥.  相似文献   
764.
Toxicity of tributyltin to willow trees   总被引:1,自引:0,他引:1  
BACKGROUND: Tributyltin is an organotin compound, used as an antifouling agent in ship paint, with heavy impact on the marine environment. Contaminated dredged harbor sludge is now dumped on land. The toxicity of tributyltin (TBT) to trees has not yet been quantified. Eventually, a vegetation cover on the dumped sludge could be established for the purpose of non-food cash crop production and phytoremediation. METHODS: The phytotoxicity of tributyltin chloride (TBTCl) and tributyltin hydride (TBTH) was measured at pH 4 and at pH 7 using the willow tree transpiration test. Different pH levels of the nutrient solutions were achieved by adding ammonium salt (low pH) or nitrate (high pH) as nitrogen source. RESULTS AND DISCUSSION: At low pH (pH 4), all trees showed symptoms of poor health. Transpiration decreased at concentrations above or equal to 0.1 mg TBTCl/l and 1 mg TBTH/L. The TBT toxicity was more pronounced at pH 7. The trees survived even the highest dose of 10 mg/l TBTCl or TBTH, although their growth and transpiration was strongly reduced. CONCLUSION: In contrast to other organisms, TBTCl and TBTH were less toxic to higher plants. RECOMMENDATIONS AND OUTLOOK: The toxicity of TBT is no hindrance for establishing vegetation on TBT-contaminated sludge. Phytoremediation and cash crop production could be possible with suitable plants.  相似文献   
765.
城市园林植物生态功能及其评价与优化研究进展   总被引:17,自引:0,他引:17  
城市当前面临着越来越严重的环境问题.园林植物因其碳氧平衡、蒸腾吸热、吸污滞尘、减菌减噪、涵养水源、土壤活化和养分循环、维持生物多样性、景观功能、防灾减灾等生态功能在缓解城市环境压力方面起着至关重要的作用.为了使城市园林植物生态功能最大限度地发挥和城市生态环境得到较大改观,综述了国内外在城市园林植物生态功能及其评价与优化等方面的最新研究成果,分析研究中存在的不足之处.  相似文献   
766.
燃煤电厂多环芳烃的生成与控制   总被引:2,自引:0,他引:2  
多环芳烃 (PAHs)对人体健康的危害极大。本文综述了燃煤电厂煤燃烧过程中多环芳烃的生成机理 (直接释放、热解合成和高温缩合机理 )和影响因素 (煤种、温度、锅炉负荷、过剩空气系数、停留时间、钙硫比和一次风 /二次风比 ) ,在此基础上介绍了煤燃烧过程中多环芳烃的各种控制技术和方法  相似文献   
767.
处理生活污水的植物品种的筛选   总被引:16,自引:0,他引:16  
以小型碎石床人工湿地生态系统和无土栽培2种方法,模拟研究了广东园林绿化中常用的27种植物对生活污水中氮、磷、COD的降解能力,表明野芋头、花叶万年青、象草、姜花、绿公主、富贵竹、再力花、大花叶万年青、芦苇、花芦苇、美人蕉、文殊兰、水芋头、风车草、红草、蜘蛛兰、千手观音、水葱和花蝴蝶等18种植物,可以作为人工湿地生态系统选种植物,从而扩大了可选植物品种范围,配合适当,可达到美化环境和净化污水2种功能,可适用于面源性水污染的治理。象草的研究表明,它是一种既有强污水降解能力又能作饲料的品种,适用于畜牧场的水污染治理。  相似文献   
768.
通过在垂直流模拟人工土柱上种植不同的花卉植物,研究了垂直流花卉人工湿地对污水COD、BOD5、TN和TP的净化效果的影响。结果表明,所选用的5种陆生花卉,甚至鲜切花卉对化粪池污水有比较好的净化效果,它们对BOD5的去除率可达到92.04%以上,对TP的去除率甚至可达到97.77%以上。而且种植花卉植物的人工湿地出水水质要好于不种植物的对照湿地系统。  相似文献   
769.
The aim of this study was to characterize the biological treatment of heavy metal-contaminated water employing Myriophyllum species, namely M. spicatum L. and M. triphyllum. Both species were found to be capable of removing cadmium (Cd) from water; the latter significantly outperformed. Myriophyllum species were treated with 0, 2, 4, 6, 8, 16 mg l−1 cadmium solutions for 24, 48, 72, 96 h, respectively. Cd uptake of both species was the lowest at 2 mg l−1 and the highest at 16 mg l−1. Concentration related cadmium stress on both species exhibit significant difference on pigment levels (8–16 mg l−1). These findings contribute to the fact that submerged aquatic plants can be used for the removal of heavy metals.  相似文献   
770.
We investigated quantitatively the sensitivity of plant species response curves to sampling characteristics (number of plots, occurrence and frequency of species), along a simulated pH gradient. We defined 54 theoretical unimodal response curves, issued from combinations of six values for optimum (opt = 3, 4, …, 8), three values for tolerance (tol = 0.5, 1.0, and 1.5, sensu ter Braak and Looman [ter Braak, C.J.F., Looman, C.W.N., 1986. Weighted averaging, logistic regression and the Gaussian response model. Vegetatio 65, 3–11]), and three values for maximum probability of presence (pmax = 0.05, 0.20, and 0.50). For each of these 54 theoretical response curves, we built artificial binary data sets (presence/absence) to test the influence of species occurrence, frequency, or number of available plots. With real data extracted from EcoPlant, a phytoecological database for French forests [Gégout, J.-C., Coudun, Ch., Bailly, G., Jabiol, B., 2005. EcoPlant: a forest sites database linking floristic data with soil characteristics and climatic conditions. J. Veg. Sci. 16, 257–260], we compared the ecological response of 50 plant species to soil pH, based first on a small data set (100 randomly sampled plots), and then based on the whole data set available (3810 plots).  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