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1.
对胶州湾李村河口4个站点沉积物中的酸可挥发性硫化物(AVS)以及同步提取金属元素(SEM,包括Cu,Cd,Ni,Pb和Zn)的含量进行测定,以研究重金属元素在河口海湾沉积物中的分布特征及影响其分布的因素。结果表明,J1站表层沉积物中同步提取金属含量高于其它站点;除J1站外其他站点的同步提取金属的总量随沉积物深度变化范围不大;J1站的SEM/AVS比值始终小于1,其他站点SEM/AVS比值只在沉积物浅表层大于1。此外,AVS和同步提取Fe的含量对沉积物中同步提取金属的分布有着重要影响,其他的因素如有机质的含量等也会对沉积物中同步提取金属的分布产生影响。  相似文献
2.
红鳍东方鲀幼鱼消化道的组织学和形态学研究   总被引:6,自引:0,他引:6       下载免费PDF全文
采用光镜和电镜技术对红鳍东方幼鱼消化道进行了组织学与形态学研究。红鳍东方消化道组织基本上分为粘膜层、粘膜下层、肌肉层和浆膜四层。口咽腔和食道前部表面被覆复层扁平上皮细胞 ,有杯状细胞、粘液细胞和味蕾分布。食道后部、胃、小肠和直肠的粘膜上皮由单层柱状上皮构成。胃 J型 ,没有胃腺存在 ,但发现有一种特殊的分泌细胞。小肠前部纵行粘膜褶发达 ,Z型 ,而后部粘膜褶不发达 ;直肠粘膜褶也很发达 ,为单个的乳头状突起。在食道与胃、胃与小肠、小肠与直肠之间均有括约肌。  相似文献
3.
花尾胡椒鲷血细胞在光镜和扫描电镜下的结构   总被引:3,自引:0,他引:3  
以花尾胡椒鲷血细胞进行光镜及扫描电镜观察。结果在血涂片中可分辨出红细胞、淋巴细胞、单核细胞、嗜酸性粒细胞、嗜中性粒细胞与血栓细胞,没有发现嗜碱性粒细胞。白细胞中,以淋巴细胞的比例最高,嗜酸性粒细胞数量最少。在扫描电镜下,红细胞椭圆形,表面光滑,无突起:而各种白细胞为圆形,细胞表面不平,具有各种突起,提示白细胞具有活跃的变形运动和吞噬能力。还见到红细胞、血栓细胞可在外周血液中通过直接分裂产生。  相似文献
4.
中国热带6种海参骨片的种类和形态研究   总被引:3,自引:0,他引:3       下载免费PDF全文
文菁  张吕平  胡超群  沈琪 《海洋学报》2009,31(2):139-145
利用扫描电子显微镜对我国6种热带海参(蛇目白尼参、玉足海参、花刺参、梅花参、子安辐肛参和巨梅花参)背脊部骨片的组成和结构进行了观察.结果表明,蛇目白尼参骨片有3种类型的花纹样体和1种杆状体;玉足海参骨片有2种类型的桌形体和1种扣形体;花刺参骨片有2种类型的桌形体、1种C形体和1种花纹样体;梅花参骨片有4种类型的杆状体;子安辐肛参骨片有1种花纹样体;巨梅花参骨片有1种杆状体、1种拟桌形体和1种颗粒体.结果显示,与之前学者光镜下观察的结果存在差异,玉足海参桌形体底盘中央是单孔而非4孔;花刺参桌形体立柱之问没有横梁连接.并发现了新的骨片类型:蛇目白尼参Ⅲ型花纹样体和杆状体;玉足海参顶部周缘小孔桌形体;花刺参顶部5簇小齿桌形体;梅花参Ⅱ型、Ⅲ型、Ⅳ型杆状体.  相似文献
5.
Vertical distribution (0–15 cm) of the macrobenthic community and its relationships to natural sediment characteristics and trace metal contents and bioavailability were studied at five locations in the lower Douro estuary, Portugal. An analysis of vertical metal distribution, for the interpretation of anthropogenic impact on the estuarine sediments, was also investigated. Sediment characterisation included organic matter, grain size, metals (Al, Fe, Cu, Pb, Cr, Ni, Cd, Zn and Mn), acid volatile sulphide (AVS) and simultaneously extracted metals (SEM). The macrobenthic community had low diversity (14 species), was dominated by small size opportunists and seemed to be controlled mainly by natural factors such as grain size distribution, Al and Fe contents and sediment depth. The vertically heterogeneous distribution of macrobenthic community appears to affect redox status of the sediments and consequently metal bioavailability. Despite anthropogenic contamination in terms of Zn, Cu, Pb, Cr and Ni having already been detected in the north bank, the analysis of vertical distribution was essential for the identification of current anthropogenic contamination in terms of Zn, Pb and Cd in the south bank.  相似文献
6.
Abstract. Zooplankton stock as well as faecal pellet numbers were monitored over 2 weeks during May in the central Baltic. Considerable changes in concentrations of chlorophyll and its derivates in copepod faecal pellets as well as in surface sediments were found during this period. The maximum concentration of 1.05 ngchl. a faecal pellet-1, measured on 12 May, decreased by the end of the month to 0.08 ngchl. a faecal pellet-1. This decrease was positively correlated with the disappearance of intact diatoms inside faeces. A flux of 1.53mgchl. a -m-2-day-1 via faecal pellets was calculated for the deep water layer (60–80 m) in mid May. This decreased to 0.005mgchl. a m-2 day-1 by the end of May. Chi. a accounted for up to 10 % of total pigments in samples from the top centimetre of the sediment surface. The means of transportation of faecal pellets as well as their function as a food supply to deeper ecosystems are discussed.  相似文献
7.
Abstract. Feeding habits of adult female Acartia tonsa and Labidocera aestiva and L. aestiva CV copepodites were examined by comparing fecal pellet contents and available phytoplankton. Samples were collected from eight stations in the northern Gulf of Mexico near the mouth of the Mississippi River. Fecal pellets of both copepods contained remains of a wide variety of chain-forming and solitary phytoplankters of various sizes, as well as remains of other crustaceans. Contents of fecal pellets generally mirrored the composition and relative abundance of fluctuating assemblages of available natural phytoplankton. Both species fed upon a wide size range of cells, from solitary centric diatoms of 2–8 um diameter up to large solitary centrics of 33–53 urn diameter. Both copepods also ingested the elongate solitary pennate diatom Thalassiothrix sp. (264–330 urn long) and chain-forming diatoms such as Skeletonema costatum. Remains of large or chain-forming diatoms and crustaceans were more dominant in fecal pellets of L. aestiva. This suggests that L. aestiva is primarily a raptorial feeder, grasping larger particles while A. tonsa is a more typical suspension feeder. Both copepods are opportunistic omnivores, however, and there is considerable overlap in their diets.  相似文献
8.
四种滤食性贝类滤食器官鳃的扫描电镜观察   总被引:1,自引:1,他引:0  
利用扫描电子显微镜技术对海湾扇贝、栉孔扇贝、太平洋牡蛎、菲律宾蛤仔4种滤食性养殖贝类的滤食器官鳃的形态结构进行了观察和比较。结果表明:1、4种贝类的鳃纤毛是极其发达的,鳃丝内侧分布大量的粘液细胞;2、海湾扇贝、栉孔扇贝鳃丝的侧纤毛不如太平洋牡蛎和菲律宾蛤仔的发达,太平洋牡蛎鳃丝内侧纤毛很发达;3、4种贝类鳃丝之间的距离都大于20μm,鳃丝间距排序为菲律宾蛤仔<海湾扇贝<栉孔扇贝<太平洋牡蛎。从电镜观察的结果看,贝类的取食与鳃的结构及鳃丝上纤毛的运动密切相关。  相似文献
9.
Abstract. In situ feeding habits of the cyclopoid copepods Oncaea venusta, Corycaeus amazonicus, Oithona plumifera , and O. simplex were investigated by scanning electron microscope examination of fecal pellets, the contents of which reflected copepod gut contents upon capture. Peilet contents were compared with assemblages of phytoplankton present in surface waters at times of copepod collection. All samples were from the northern Gulf of Mexico. All four copepods fed upon phytoplankton and O. venusta also ingested other crustaceans. Dominant components of fecal pellets generally did not mirror those of available phytoplankton assemblages. In some cases, O. venusta ingested primarily larger-sized particles even when these were not most abundant, and in other cases it did not ingest large cells even when they were present in bloom concentrations. The presence of small (< 2–5 urn diameter) centric diatoms in O. venusta pellets suggests the possibility of feeding by mechanisms other than suspension or raptorial feeding. Limited observations suggest that C. amazonicus and O. plumifera may feed raptorially on larger particles even when these are not particularly abundant, and that the small O. simplex (< 500 nm total length) feeds mainly upon nanoplankton. It appears that cyclopoid feeding mechanisms are complex, and likely more so than those of many calanoids.  相似文献
10.
Abstract. The in situ diet of the copepod Undinula vulgaris was examined by comparing contents of fecal pellets produced on natural food with assemblages of available phytoplankton. Samples were collected in continental shelf waters of the northern Gulf of Mexico. U. vulgaris was an indiscrimi-nant suspension feeder, ingesting a broad size, shape, and taxonomic array of phytoplankters. Contents of fecal pellets generally matched those of available phytoplankton assemblages. The presence within the same fecal pellets of remains of microplankters ranging over two orders of magnitude in longest dimension suggests that feeding is nonselective, and that U. vulgaris may rapidly switch between several modes of feeding.  相似文献
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