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   216篇
  免费   11篇
  国内免费   8篇
安全科学   14篇
废物处理   7篇
环保管理   17篇
综合类   56篇
基础理论   35篇
环境理论   1篇
污染及防治   48篇
评价与监测   38篇
社会与环境   12篇
灾害及防治   7篇
  2023年   5篇
  2022年   6篇
  2021年   9篇
  2020年   8篇
  2019年   3篇
  2018年   13篇
  2017年   7篇
  2016年   16篇
  2015年   7篇
  2014年   12篇
  2013年   14篇
  2012年   13篇
  2011年   18篇
  2010年   11篇
  2009年   6篇
  2008年   5篇
  2007年   9篇
  2006年   6篇
  2005年   2篇
  2004年   8篇
  2003年   6篇
  2002年   17篇
  2001年   8篇
  2000年   6篇
  1999年   5篇
  1997年   3篇
  1996年   1篇
  1995年   1篇
  1993年   3篇
  1980年   2篇
  1979年   1篇
  1977年   1篇
  1975年   1篇
  1964年   1篇
  1930年   1篇
排序方式: 共有235条查询结果,搜索用时 15 毫秒
101.
湖北的气候生产力与农业持续发展   总被引:12,自引:0,他引:12  
基于对湖北省主要农作物气候生产力的估算,分析了目前气候生产力利用的现状,由于受到自然条件和社会条件的限制,在目前大田生产的条件下,湖北粮食气候生产力利用率相对较低,即使是利用率稍高的中稻,其历史最高产量也仅为气候生产力的一半,气候生产潜力较大。因此,如何加强农业气候生产力的开发利用,最大限度的发挥气候资源的作用,将是实现湖北农业持续发展需要解决的重大问题之一。  相似文献   
102.
Environmental Science and Pollution Research - In this study, pollens were collected from 25 different locations of Northern Turkey to investigate pollution monitoring. Surface chemistry of pollen...  相似文献   
103.
分子结构在腐殖酸对菲吸附行为中的影响   总被引:13,自引:0,他引:13  
用连续碱提取具有不同结构组成特征的腐殖酸级分,考察了分子结构在腐殖酸对菲吸附行为中的影响,结果表明:随着腐殖酸中元素碳、表观分子量以及脂肪碳含量的增加,腐殖酸对菲的吸附能力和吸附的非线性特征都呈增强趋势;相反,随着腐殖酸中元素氧和芳香碳含量的增加,腐殖酸对菲的吸附能力和吸附的非线性都逐渐减弱,这主要与结构中极性官能团所连位置有关.  相似文献   
104.
105.
A better public perception and knowledge on land degradation increases the individual and collective responsibility in land use and land management. Based on interviews, this paper presents results of evaluation of public perception and attitude towards degrading phenomena in the central part of Romania, an area prone to geomorphologic processes, with different land uses and a high proportion of degraded land. The research reveals natural causes, improper land use, categories of land owned, socio-economic causes and involvement of institutions as key aspects of public perception. Our research could be useful in the identification and design of measures in regional planning to attract population in prevention, mitigation and rehabilitation actions on degraded land.  相似文献   
106.
通过对一种国外应用较广的污泥虹吸系统的适应化改造可行性论证,对其实施了一种在改进效果、改造风险、改造难度以及成本方面都较优的改造方案。通过1a的试运行,整个系统运转正常,整体改造十分成功。  相似文献   
107.
Polychlorinated biphenyl (PCB) and organochlorine pesticide (OCP) levels in fat tissue of red and fallow deer (Cervus elaphus L. and Dama dama L.) from two inland and an Adriatic area were established. Of 17 analysed PCBs, PCB-28, PCB-138, PCB-153, PCB-180 and PCB-118 were found in all samples, whilst PCB-101 and PCB-170 were found in more than 50% of samples. They ranged between 0.03 and 5.98 ng g(-1) fat weight. Of seven analysed OCPs, HCB, γ-HCH and 1,1-dichloro-2,2-di(4-chlorophenyl)ethylene (DDE) were found in all samples, whilst β-HCH was found in more than 50% of samples. They ranged between 0.17 and 22.14 ng g(-1) fat weight. The dominating compounds were DDE, PCB-138, PCB153, PCB-118 and PCB-180. According to the Duncan multistage test, the levels of PCB-138, PCB-153, PCB 170 and PCB-180 were significantly higher in perirenal fat samples of specimens taken from the Adriatic area. DDE was significantly higher in the inland deer samples. Some species differences were determined and were mostly related to higher PCB and β-HCH levels in fallow deer samples and higher DDE levels in red deer samples. No sex difference was established. As for age, significantly higher levels of PCB-118 and PCB-52 were found in fawns.  相似文献   
108.
According to the International Decade for Natural Disaster Reduction (IDNDR 1990–1999), the risk indicates potential losses due to particular natural phenomenon, and these could be reduced by improving of prevention and education. People perceive these losses differently depending on phenomenon occurrence, severity, and impact in time. Starting from this idea, this research presents public perception on land degradation through erosion in a small area from the central part of Romania (south-west of Transylvanian Depression). The research was based on a questionnaire consisting of 16 questions. The items were structured by issues: awareness assessment regarding hazard and risk phenomena, assessment of type of property and land use, assessment of knowledge and information on the possible production of negative effects by natural phenomena, and evaluation of land owners’ attitudes towards the occurrence of erosion on their land. Results reveal that the public perception on erosion is weak. This process is perceived as insignificant due to lack of phenomenon knowledge and especially because of scarcity preoccupation in land’s quality monitoring. Even though the owned lands are affected by erosion forms, the owners are not aware of the phenomenon that generates them. Material damages caused by erosion, loss of soil quality, and land fertility decrease are less perceived because the economic losses fill only at long term. This perception leads to underestimating erosion risk compared to other natural phenomena and to a passive attitude towards this particular phenomenon.  相似文献   
109.
本文介绍了微藻生物柴油的优势及技术进展,以及国内外培养微藻制备生物柴油的研究现状,探讨了微藻生物柴油生产关键技术环节及存在的主要问题,展望了微藻生物柴油的未来发展趋势和潜在的应用前景。  相似文献   
110.
结合桐柏县的实例,对县域生态功能区划分的原则和方法进行初步探讨。综合利用3S技术对县域生态敏感性和生态服务功能重要性的分析和评价,提出桐柏县生态服务功能区划的初步方案。将桐柏县划分为生态支持区,产品供给区,生态调节区。简要分析了各功能区在桐柏县经济可持续发展中的地位和作用,指出各区协调发展的方向和途征。  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