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   199篇
  免费   1篇
  国内免费   3篇
安全科学   3篇
废物处理   39篇
环保管理   8篇
综合类   26篇
基础理论   42篇
污染及防治   67篇
评价与监测   7篇
社会与环境   9篇
灾害及防治   2篇
  2023年   1篇
  2022年   2篇
  2021年   4篇
  2020年   2篇
  2018年   6篇
  2017年   2篇
  2016年   3篇
  2015年   3篇
  2014年   3篇
  2013年   12篇
  2012年   4篇
  2011年   13篇
  2010年   3篇
  2009年   16篇
  2008年   10篇
  2007年   15篇
  2006年   17篇
  2005年   12篇
  2004年   11篇
  2003年   16篇
  2002年   5篇
  2001年   6篇
  2000年   2篇
  1999年   4篇
  1997年   6篇
  1996年   2篇
  1995年   4篇
  1994年   3篇
  1993年   1篇
  1991年   1篇
  1989年   2篇
  1987年   1篇
  1984年   3篇
  1977年   1篇
  1976年   1篇
  1973年   1篇
  1972年   1篇
  1969年   1篇
  1968年   1篇
  1965年   1篇
  1961年   1篇
排序方式: 共有203条查询结果,搜索用时 15 毫秒
91.
92.
93.
94.
Tareq SM  Tanoue E  Tsuji H  Tanaka N  Ohta K 《Chemosphere》2005,59(11):1655-1665
Evidence of changing vegetation in the tropical wetland (Rawa Danau, west Java, Indonesia) over the past 7428 years is illustrated by elemental (soot) carbon (EC) and n-alkane composition of sedimentary geolipids. In this study, vegetation changes and relevant controlling factors (e.g. forest fire and climate change) were documented on a decadal to centennial scale. The n-alkane composition that changes with depth might record changes in sources of organic matter (OM) in the wetland. The presence of EC (0.01–0.24% of organic carbon: OC) during late (0–1700 cal. year BP) and mid (3500–4500 cal. year BP) Holocene (at depths 0–50 cm, and 160–210 cm) indicated that large-scale forest fires severely affected the tropical vegetation. The hydrocarbon indices (CPI: carbon preference index, MCN: mean carbon number, and HVI: hydrocarbon vegetation index) significantly correlated with one another while a comparison of EC profile with the profiles of hydrocarbon indices indicated that n-alkane composition of the geolipid in lake sediment could record signatures of changes in catchment vegetation. Forest fire and vegetation changes might be related to regional climatic shifts relating to ENSO activity as well as being influenced by human influences.  相似文献   
95.
Potassium Bromate was administered orally to rats and its fate in the body was studied. The bromate was rapidly absorbed from the digestive tract and was partly excreted in the urine within two hours of administration. No bromate was detected in body organs or in the blood 24 hours after dosing. Excretion of bromate into the urine was proportional to the dose, except that at 2.5mg/kg or less no excretion was observed. The administration of bromate increased the bromide concentration in various organs and in urine.  相似文献   
96.
A limited amount of information exists regarding the relationship between the chemical form of copper and the formation of chlorinated aromatics in fly ash. To understand the effects of the various forms of copper on the formation of chlorinated aromatics in real fly ash, we determined the chemical forms of copper present in various types of real fly ash using X-ray absorption near edge structure (XANES) and evaluated the relationship between the chemical forms of copper and the formation of chlorinated aromatics. Copper chloride hydroxide (CuCl2 x 3Cu(OH)2) and cuprous chloride (CuCl) were the predominant copper species found in real fly ash. Although pure cupric chloride (CuCl2) is known to be the most active catalyst for the formation of chlorinated aromatics under experimental conditions with synthetic fly ash, CuCl2 was not found in every real fly ash sample. The amount of copper chloride hydroxide was positively correlated with the formation of chlorinated aromatics in real fly ash and is, consequently, considered to be one of the key species involved in the formation of chlorinated aromatics.  相似文献   
97.
Cosmogenic (10)Be, known for use in dating studies, unexpectedly is also produced in nuclear explosions with an atom yield almost comparable to (e.g.) (137)Cs. There are major production routes via (13)C(n, alpha)(10)Be, from carbon dioxide in the air and the organic explosives, possibly from other bomb components and to a minor extent from the direct fission reaction. Although the detailed bomb components are speculative, carbon was certainly present in the explosives and an order of magnitude calculation is possible. The (n, alpha) cross-section was determined by irradiating graphite in a nuclear reactor, and the resulting (10)Be estimated by Accelerator Mass Spectrometry (AMS) giving a cross-section of 34.5+/-0.7mb (6-9.3MeV), within error of previous work. (10)Be should have applications in forensic radioecology. Historical environmental samples from Hiroshima, and Semipalatinsk (Kazakhstan) showed two to threefold (10)Be excesses compared with the background cosmogenic levels. A sample from Lake Chagan (a Soviet nuclear cratering experiment) contained more (10)Be than previously reported soils. (10)Be may be useful for measuring the fast neutron dose near the Hiroshima bomb hypocenter at neutron energies double those previously available.  相似文献   
98.
Various experiments were conducted to examine the effects of degradation products on organisms. Fenitrothion (MEP) emulsions adjusted to pH 10 or 14 were degraded by exposure to natural sunlight in winter with heat. Medaka eggs were exposed to various concentrations of the degraded solutions and an untreated MEP emulsion for 5 days starting 4-5 h following fertilisation. The eggs were then allowed to develop in dechlorinated tap water until the fish reached 3 months of age. The hatching rate and rate of survival in the degraded solutions tended to be lower than those in the untreated MEP emulsion, and the incidence of abnormal fry in the degraded solutions was higher than that of the untreated MEP emulsion. It thus appears that degradation products formed by MEP have toxic effects on medaka.  相似文献   
99.
Ichiura H  Kitaoka T  Tanaka H 《Chemosphere》2003,51(9):855-860
The photocatalytic oxidation of nitrogen oxides (NO(x)) over titanium dioxide (TiO(2)) sheets containing metal compounds (MCs) had been studied. Calcium oxide (CaO), magnesium oxide (MgO), calcium carbonate (CaCO(3)), aluminium oxide (Al(2)O(3)) and ferric oxide (Fe(2)O(3)) were used as MCs. Al(2)O(3) and Fe(2)O(3) added to the TiO(2) sheet did not affect the photooxidation of nitrogen oxides (NO(x)). The CaO sheet treated with TiO(2) sol had the greatest efficiency as a NO(x) remover under UV irradiation. It is believed that CaO has a high adsorptivity for nitrogen dioxide (NO(2)) and nitric acid (HNO(3)). The amount of NO(x) removed by a TiO(2) sheet including MC showed a tendency to increase with increasing pH of the MC suspension, i.e. there is a good correlation between the alkalinity of the MC and the retention of NO(2) and HNO(3).  相似文献   
100.
Keiji Abe  Keiichi Tanaka 《Chemosphere》1997,35(12):2837-2847
Mono-, di- and trichlorophenol including different isomers were degraded by O3, O3 + UV and O3 + UV + Fe3+. Disappearance rates are nearly identical among three ozonations. Whereas TOC elimination was not completed by ozone alone. UV illumination accelerated TOC elimination rate and the addition of Fe3+ (O3 + UV + Fe3+) further accelerated it. TOC elimination rates among different chlorophenols were in the order of mono > di > tri. The effect of Fe3+ was largest on the degradation of trichlorophenol. Hydroxylated aromatics, organic acids, formaldehyde and acetone were detected as intermediates.  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