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   79篇
  免费   4篇
  国内免费   29篇
安全科学   3篇
废物处理   2篇
环保管理   2篇
综合类   53篇
基础理论   12篇
污染及防治   20篇
评价与监测   10篇
社会与环境   5篇
灾害及防治   5篇
  2023年   3篇
  2022年   2篇
  2021年   5篇
  2020年   1篇
  2019年   2篇
  2018年   5篇
  2017年   3篇
  2016年   1篇
  2015年   4篇
  2014年   3篇
  2013年   12篇
  2012年   3篇
  2011年   2篇
  2010年   4篇
  2009年   6篇
  2008年   2篇
  2007年   4篇
  2006年   7篇
  2005年   7篇
  2004年   3篇
  2003年   8篇
  2002年   3篇
  2001年   3篇
  2000年   1篇
  1999年   4篇
  1998年   2篇
  1997年   3篇
  1995年   2篇
  1994年   3篇
  1993年   2篇
  1992年   1篇
  1988年   1篇
排序方式: 共有112条查询结果,搜索用时 15 毫秒
1.
2.
A study on the orbit of air temperature movement   总被引:1,自引:0,他引:1  
In this paper, we describe an air temperature movement by mapping its time series to the polar coordinates: the value of the time series is plotted on the radial coordinate and the time on the angular coordinate. In this way, both the yearly and daily air temperature movements from five different locations of China are used to demonstrate that, in an intuitionistic view, air temperature movement is neither random nor chaotic, but has its own orbit. We then propose an elliptic orbit model for the air temperature movement. Our proposed model provides quite good results when it is applied to the evaluation of yearly air temperature movements in eight locations in various parts of the world, and the evaluation of daily air temperature movements in five locations in Hunan Province of China on December 17, 2005. Results show that our approach provides a concise and helpful model for air temperature analysis.  相似文献   
3.
分析了二英的化学结构与毒性的关系,二英的来源,对人体健康的潜在危害以及可能造成的环境污染,提出了防治措施。  相似文献   
4.
A fetus with multiple structural defects was seen at prenatal ultrasound examination. After termination of the pregnancy a bilateral cleft lip, alveolus, and palate; micrognathia; and webbed joints were seen. Fetal tissues showed indications of infection, intranuclear inclusion bodies, chronic stress, haemolysis, arterial wall damage, and profuse haemorrhage. Parvovirus B19 DNA was detected in fetal tissues by dot hybridization after polymerase chain reaction. The possibility of parvovirus B19 infection leading to congenital malformations is discussed.  相似文献   
5.
受污染地表水体生物修复技术研究进展   总被引:4,自引:0,他引:4  
主要介绍了受污染地表水体生物修复技术的类型及特点,综述了国内外关于受污染地表水体生物修复技术研究及应用的现状,并对生物修复技术的研究及应用进行了展望.  相似文献   
6.
矿物的相转变曾被认为是矿物包裹体爆裂法测温的影响因素之一。本文从矿物在加热过程中发生相转变和内部气液包裹体爆裂二者不同的作用机理,以及在爆裂曲线上不同的反映出发,通过一些实验和实例对比,探讨了矿物相变对爆裂法测温实际效果的影响,和所谓石英“相变峰”在岩体对比等方面的实际意义,得出矿物相变对爆裂法测温不会产生有害影响的结论。  相似文献   
7.
长江中下游的侵入岩体,尤其是燕山期的侵入岩体面广量大.它们与区内铜、铁、金等矿产关系密切。本文通过对侵入岩体地质特征、岩石化学成分等对比研究后,总结出如下几个特点:1、侵入体主要形成时代为135-95Ma,自西向东有逐渐变新的趋势;2、与成矿有关者多数是复式岩体,与铜矿化有关的主要是燕山早期侵入岩,与铁矿化有关的则主要是燕山晚期侵入岩;3、多数岩体受到过中、下三叠统蒸发岩层(膏盐层)的同化混染;4、岩体含碱质高,在Na2O-SiO2关系图上显示出二者没有相关性;5、侵入体中的铜有可能提供部分铜矿床的物源;6、岩石化学成分上某些组分的对比研究表明,成铜矿与成铁矿岩体之间、成矿岩体和无矿岩体之间有一定程度的差异。  相似文献   
8.
Amino acids constitute one of the largest inputs of organic nitrogen (N) to most polar soils and have been hypothesized to be important in regulating vegetational succession and productivity in Arctic ecosystems. Our understanding of amino acid cycling in these soils, however, is poor. The aim of this study was to investigate the size and rate of turnover of the amino acid pool in a range of Arctic and Antarctic soils. Our results indicate that in polar soils with either high or low ornithogenic inputs the amino acid pool is small in comparison to the inorganic N pool (NO3 and NH+4). The free amino acid pool constituted only a small proportion of the total dissolved organic nitrogen (DON) pool in these soils. Here we show that these low concentrations may be due to rapid use by the soil microbial community in both Arctic and Antarctic soils. The turnover of the amino acid pool in soil was extremely rapid, with a half-life ranging from 2 to 24 h, indicating that this N pool can be turned over many hundred times each summer when polar soils are frequently unfrozen. The implications of amino acids in N cycling and plant and microbial nutrition are discussed.  相似文献   
9.
The Southern Ocean is one of the most rapidly changing ecosystems on the planet due to the effects of climate change and commercial fishing for ecologically important krill and fish. Because sea ice loss is expected to be accompanied by declines in krill and fish predators, decoupling the effects of climate and anthropogenic changes on these predator populations is crucial for ecosystem‐based management of the Southern Ocean. We reviewed research published from 2007 to 2014 that incorporated very high‐resolution satellite imagery to assess distribution, abundance, and effects of climate and other anthropogenic changes on populations of predators in polar regions. Very high‐resolution imagery has been used to study 7 species of polar animals in 13 papers, many of which provide methods through which further research can be conducted. Use of very high‐resolution imagery in the Southern Ocean can provide a broader understanding of climate and anthropogenic forces on populations and inform management and conservation recommendations. We recommend that conservation biologists continue to integrate high‐resolution remote sensing into broad‐scale biodiversity and population studies in remote areas, where it can provide much needed detail. Aplicaciones de Imágenes de Muy Alta Resolución en el Estudio y Conservación de Grandes Depredadores en el Océano Antártico  相似文献   
10.
用GC/MS,对金华地区3个采样点、四个季节,225个PM_(2.5)样品中10种极性有机示踪化合物进行了分析,包括天然源:3个异戊二烯SOA示踪物、1个α-蒎烯SOA示踪物和2个真菌孢子示踪物,和人为源:1个甲苯SOA示踪物、3个生物质燃烧示踪物.结果表明,异戊二烯SOA示踪物浓度为3.41~48.50 ng·m~(-3),α-蒎烯SOA示踪物浓度为2.45~25.40 ng·m~(-3),甲苯SOA示踪物为4.75~39.80 ng·m~(-3).各SOA示踪物均有明显的季节变化,其中,异戊二烯SOA示踪物呈夏季秋季≈春季冬季,α-蒎烯SOA示踪物夏季春季≈秋季冬季,甲苯SOA示踪物秋季夏季春季冬季.估算得出甲苯SOC对OC的贡献为3.03%~24.50%,而来源于生物质燃烧的有机碳对OC的贡献可以达到1.23%~42.80%.表明人为源排放前体物的二次转化以及生物质燃烧是金华地区大气细颗粒物污染的重要来源.  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