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   54篇
  免费   3篇
  国内免费   9篇
大气科学   7篇
地球物理   11篇
地质学   9篇
海洋学   29篇
综合类   7篇
自然地理   3篇
  2018年   1篇
  2016年   1篇
  2015年   2篇
  2014年   6篇
  2013年   1篇
  2011年   2篇
  2010年   3篇
  2009年   6篇
  2008年   4篇
  2007年   3篇
  2006年   1篇
  2005年   5篇
  2004年   5篇
  2003年   1篇
  2002年   5篇
  2001年   1篇
  2000年   5篇
  1999年   5篇
  1998年   2篇
  1997年   2篇
  1995年   1篇
  1988年   1篇
  1985年   2篇
  1982年   1篇
排序方式: 共有66条查询结果,搜索用时 15 毫秒
41.
Glass-plate sampling during 1988- 1999 in Daya Bay and suitable corresponding analytical methods were used for the measurement of dissolved trace metals, dissolved organic carbon, biological oxygen demand, chemical oxygen demand, salinity of the sea surface mierolayer and subsurface water. Apparent enrichment mechanism and diurnal variation have been revealed for dissolved trace metals in the microlayer in Daya Bay. The more dissolved organic matter was enriched in the sea surface microlayer, the more dissolved trace metals were enriched in the layer. The organic matter played an important role in the enrichment process. The diurnal variations of dissolved trace metals showed that their concentration was apparently inversely related to the tide activity that the concentration was low during rising tide, but high during falling tide. The behavior of dissolved trace metals expressed by the diurnal variation was clearly opposite to that of salinity.  相似文献   
42.
The sea-surface microlayer is an important interface between the atmosphere and ocean and a collection point for many anthropogenic materials including potentially toxic metals. We developed a glass plate sampler to collect the upper 30 to 55 micrometers of the sea surface. Samples of the microlayer and subsurface bulk water from an urban and rural bay were analysed for concentrations of Pb, Zn, Cu, Cd and Fe. Metal concentrations in both the microlayer and bulk water were generally 2 to 15 times greater in the urban than in the rural bay. Concentrations of metals in the microlayer of both bays averaged 6 to 65 times greater than those in the bulk water. In the urban bay, microlayer concentrations of Pb, Zn and Cu from 10 to > 100 μg 1?1 were common. Measured microlayer metals concentrations agree well with those predicted from atmospheric deposition rates using a previously derived empirical model developed from laboratory microcosm studies. Further work will be required to determine whether or not these high microlayer metal concentrations contain significant biologically available fractions which could impact fisheries recruitment of larval icthyoneuston.  相似文献   
43.
从大气环流,海温,太阳黑子,台风等方面分析了2000,2001两年河南汛期降水差异原因,结果表明,500hPa环流形势的差异是两年降水差异的原因之一;2001年登陆台风较多,且多位于水汽通道上,阻挡水汽向河南输送,这是2001年较2000年干旱的又一原因。  相似文献   
44.
Over 50 seawater samples from two different sites—Barcelona (Spain) and Banyuls-sur-Mer (France)—were analyzed in order to study the extent and postulate the processes driving the enrichment of hydrophobic organic pollutants in the sea surface microlayer (SML). A number of individual polychlorinated biphenyl (PCB) congeners (41) were measured to study their partitioning between the particulate (fraction > 0.7 μm) and the dissolved + colloidal phases (fraction < 0.7 μm), with the latter being differentiated into estimated dissolved and colloidal phases. In addition, several organochlorine pesticides were also measured, namely, HCB, α-HCH, γ-HCH, 4,4′-DDE, 4,4′-DDD and 4,4′-DDT. The presence of PCB congener profiles found in the SML suggests a dynamic coupling with the atmosphere in Banyuls sampling site, whereas offshore Barcelona the presence of highly chlorinated congeners was due to persistent sediment resuspension. The average PCB concentration in the SML dissolved + colloidal phase were higher in Banyuls (7.8 ng L 1) than in Barcelona (3.6 ng L 1) samples, but in the particulate phase concentrations were higher in Barcelona (3.2 ng L 1) to that of Banyuls (1.4 ng L 1). However, PCB concentrations in the SML generally also showed large variability. Enrichment factors of PCBs and other organochlorine compounds in the SML with respect to the underlying water column ranged from 0.2 to 7.4. This may be explained for both the dissolved + colloidal and particulate phases by the enrichment in the SML of organic carbon (OC) as discerned from particle–water and colloid–water partitioning.  相似文献   
45.
A survey of sea-surface microlayer (SSML) toxicity was initiated off the Florida Keys in early 1993. Ex situ toxicity tests, based on the development of the sea urchin, Lytechinus variegatus, demonstrated that 59.2% of SSML samples taken from visibly slicked areas (n=27) were toxic compared to collected subsurface water. A random subset of samples tested a second time using a fish early life-stage test with embryos from the spotted seatrout, Cynoscion nebulosus, confirmed the presence of the toxicant. Results from a partial toxicity identification evaluation (TIE) procedure indicated that an organic compound(s) containing a non-polar functional group was the primary determinant of toxicity in all of the SSML samples tested. While subsequent GC-MS analyses failed to identify a specific compound, they did tend to rule out common xenobiotics, such as organochlorine pesticides as potential toxicants. Preliminary tests, done by an outside laboratory, indicated that two of the most toxic SSML samples contained a brevetoxin, a biotoxin produced by Gymnodinium breve. This is the first report of natural toxins concentrating in the SSML; however, without a completed TIE, including a Phase III—toxicity confirmation procedure, the identification of any toxic agent remains speculative.  相似文献   
46.
大亚湾海区微表层、次表层BOD和COD的研究   总被引:5,自引:0,他引:5  
研究表明,大亚湾海区海--气界面微表层对BOD和COD均产生了富集,但富集概率有所差别,BOD为87.5%,COD为100%,平均富集因数,BOD为3.00,COD为3.28.BOD和COD与相应的营养盐和Chl·a的回归分析表明,其相关显著性水平,微、次表层优于表、底层.  相似文献   
47.
Determination of apparent sampling thickness of sea surface microlayer   总被引:5,自引:0,他引:5  
IwrRODUtvIONTheseasurfacendcrolayer(SML)isathinair-seainterfacelayerwithphySical,chdricalandbiologicalproperties.OrganicmateriaIs,haceAnIs,nutrientS,particulatCrnat-terandplanktonaregenefallyenrichedintheSML(Hardy,JT.etal.,l98O,Wunams,P.M.etal.,1986).ThesamPlersforcolledingtheSMLwerernainlyglassplatespearvey,G.W.etal.,l972,l985;ZhangZhengbinetal.,l996),rotatingdrums(Harvey,G.W.,1966,Daumas,R.A.l976),screensgurmt,W.D.,l965,Piotrowicz,S.R.etal.,l972,Carison,D.J.,l982),funneIs…  相似文献   
48.
《Marine pollution bulletin》2014,78(1-2):110-117
Sea microlayer (SML) and subsurface water (SSW) samples were collected around Xiamen Island to study the enrichment and partitioning of polycyclic aromatic hydrocarbons (PAHs). Total PAH concentrations ranged from 93.43 to 411.05 ng L−1 in the SML and 49.29–279.42 ng L−1 in the SSW. Compared with the results of previous studies before pollution control measurements, PAHs levels decreased significantly. The enrichment factors (EFs) of dissolved and particulate PAHs varied from 0.68 to 2.71 and 0.43–3.56. EFs showed the consistent enrichment trends with sites and exhibited different enrichment characteristics between 2 and 3 ring PAHs and 4 ring PAHs. Furthermore, the much higher concentrations of BaP (strong carcinogenicity) were accompanied by higher EFs in the SML samples from the Western Xiamen Harbour, which together indicated the risk of impacts to the fish eggs that usually float on the SML water after exposure to oil spills and combustion, contributed directly by the port and shipping activities.  相似文献   
49.
为研究溢油对海面电磁散射的影响,作者根据海面复合微波散射模型理论和蒙特卡洛统计模型理论,通过引入单分子油膜的黏性阻尼,对粗糙的溢油海面进行建模,定量分析溢油对海浪谱和海面后向散射系数值两个方面的影响。为实现基于X波段雷达海面溢油检测提供理论支撑,有助于解决溢油检测中的虚警率高的问题。  相似文献   
50.
黄海海水微表层和次表层中挥发性卤代烃的浓度和分布   总被引:1,自引:0,他引:1  
挥发性卤代烃(VHCs)是大气中的痕量气体,对臭氧层损耗和温室效应有重要作用。海洋是大气中VHCs的重要自然排放源,开展海洋VHCs的研究有助于了解海洋对大气VHCs和全球变暖的贡献。于2006年4月对中国黄海微表层、次表层中6种挥发性卤代烃的浓度和分布进行了研究。结果表明:微表层中CHCl3,CCl4,C2HCl3,C2Cl4,CHBrCl2和CHBr2Cl的浓度分别为2.91~45.88(10.31±8.07),0.20~2.74(0.80±0.64),1.13~32.07(11.43±6.53),0.16~73.68(17.10±15.57),0.08~1.64(0.43±0.34)和0.22~14.20(4.35±3.53)pmol.dm-3;次表层中各浓度分别为2.02~38.55(10.38±7.80),0.12~2.14(0.80±0.54),1.50~26.80(11.90±6.74),0.96~73.45(16.58±14.97),0.06~1.88(0.42±0.34)和0.27~25.24(4.95±4.92)pmol.dm-3;总的来说,在微表层、次表层中CCl4,CHCl3,C2HC...  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