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101.
虾池浮游微藻的种类组成、数量和多样性变动   总被引:5,自引:1,他引:5  
报道了在集约化养虾中应用有益微生物制剂对虾池浮游微藻的影响,分析了整个养虾周期浮游微藻的种类组成、生物量、优势种及多样性指数的周期变化情况。结果表明,早期虾池浮游微藻细胞数量维持在1×103~3×103mL-1的水平,养殖中期开始呈指数增长状态,后期达到顶峰,并维持在70×103~160×103mL-1的水平,生物量比自然海区高。优势种类明显,前期为中肋骨条藻和伏氏海毛藻等硅藻类,后期则为绿球藻和栅列藻等绿藻类,水色及藻相呈良好状态,而不施加芽孢杆菌制剂的对照池则在后期出现较大比例的有害的蓝藻。虾池藻类多样性指数、均匀度指数和种类丰度均呈现前期高后期低的趋势,而优势度指数则相反,呈现前期低后期高的趋势。浮游植物的多样性指数为0.60~3.80,平均为1.88,均匀度指数为0.14~0.83,平均为0.45;种类丰度为0.80~2.46,平均为1.38;优势度指数在0.17~0.85,平均为0.41。多样性指数和均匀度均比粤东海域低,但优势度则甚高。  相似文献   
102.
大菱鲆鳍细胞系的建立   总被引:3,自引:1,他引:2  
建立大菱鲆(Scophthalus maximus)鳍细胞系,文中采用胰蛋白酶、透明质酸酶和Ⅱ型胶原酶消化法启动大菱鲆鳍组织的原代培养,并通过培养液配方和培养条件的优化成功进行大菱鲆鳍细胞的继代培养。研究结果显示,在pH=7.0~7.4、温度20~24℃的培养条件下,培养于含有表皮细胞生长因子、碱性成纤维细胞生长因子、羧甲基壳多糖、N-乙酰葡萄糖盐酸盐的Leibovitz-15培养液(20%胎牛血清)中的大菱鲆鳍细胞,其生长分裂状况最好,细胞形态为成纤维细胞样。经继代培养后,细胞生长分裂依然十分旺盛,第60代大菱鲆鳍细胞系的群体倍增时间为62.4 h,虽然出现了染色体的非整倍性,但其特征性染色体仍为44条。该细胞系细胞经液氮冻存后仍保持有原有形态和较高存活率。现已成功建立了连续性大菱鲆鳍细胞系,目前已传至第65代。该细胞系的建立对于查清病毒对大菱鲆细胞的感染途径与感染机理等具有重要的理论意义,对于病毒疫苗研制具有重要应用价值。  相似文献   
103.
This paper outlines a one-dimensional,heightdependent bin model with detailed microphysical processes in which ice splinters are produced by a riming process.The model is then applied to simulate the shift of particle size distribution effected by the secondary ice production process within clouds with different generating cells and cloud top temperatures.The result of model simulations reveals the general effects of cloud updrafts on increasing ice particle concentration by extending the residence time of ice particles in clouds and providing sufficiently large supercooled water droplets.The rimesplintering mechanism is more effective in clouds with lower ice seeding rates than those with higher rates.Evolutions of hydrometeor size distribution triggered by the rime-splintering mechanism indicate that the interaction between large ice particles and supercooled water drops adds a "second maximum" to the primary ice spectra.  相似文献   
104.
对斜带石斑鱼(Epinephelus coioides)稚鱼在摄食和饥饿2种营养条件下胃肠道中5种内分泌细胞的形态、定位和分布密度进行比较研究.采用免疫细胞化学方法和5-羟色胺(5-hydroxytryptamine,5-HT)、生长抑素(somatostain,Som)、胃泌素(gastrin,Gas)、P物质(substance P,SP)及神经肽Y(neuropeptide,NPY)的特异性抗血清进行胃肠道免疫活性细胞的检测.结果显示,5种胃肠激素内分泌细胞在斜带石斑鱼稚鱼胃肠各部位均有开放型和封闭型2种,饥饿对细胞的形态有所影响但不明显.统计分析结果显示5种内分泌细胞在摄食组和饥饿组的斜带石斑鱼稚鱼胃肠各部位的分布密度存在明显差异.在贲门胃,饥饿组5-羟色胺和生长抑素免疫活性细胞数量上升,为正常摄食组的2.2倍和12.4倍,而在胃体和幽门胃则下降了1/3~5/6;饥饿组的胃泌素和P物质免疫阳性细胞数量在幽门胃下降为1/2,在肠道则有升有降;唯有神经肽Y免疫活性细胞在摄食组和饥饿组2组间没有显著差异.这些结果表明,胃肠激素参与调控斜带石斑鱼稚鱼胃肠的消化和吸收功能.一旦发生饥饿,斜带石斑鱼稚鱼胃肠激素细胞的分泌活性发生相应改变,最终可能会导致细胞功能失调,成为幼体死亡的因素之一.  相似文献   
105.
采用ANAE组化方法(α-醋酸萘酯酶染色法)和ABC免疫组化方法(亲合素-生物素-过氧化物酶复合物法)分析了1龄红笛鲷成鱼的胸腺、头肾和脾脏中IgM+细胞(具有免疫球蛋白分子IgM的细胞)、ANAE+ T细胞的分布。结果表明,三个淋巴器官皆有IgM+细胞、ANAE+ T细胞;胸腺皮质区IgM+细胞数量最多,其次是头肾、胸腺髓质区、脾脏;ANAE+ T细胞以脾脏中数量居多,其次是头肾、胸腺髓质区、胸腺皮质区;ANAE+ T细胞在三个器官中多呈均匀分布,而IgM+细胞在血管、胸腺小体、黑色素巨嗜细胞中心等的外周呈密集分布。实验结果进一步证明了胸腺中的T细胞多为不成熟的T细胞,此外,还含有大量的IgM+细胞;而脾脏、头肾内的ANAE+ T细胞多于胸腺,推测胸腺成熟的T淋巴细胞迁移到头肾和脾脏。  相似文献   
106.
The statistical technique of discriminant analysis is used to define target areas for detailed general exploration given only general geological information and aeromagnetic anomaly blues. In the test area, located in Central Norway, on-going exploration surveys have revealed the presence of mineralization; however, it still has not been determined if any of the sites will beeconomically feasible. The area was divided into 1400 1-km × 1-km cells by superimposing square grid on 1:50,000-scale geological and geophysical maps. Later the area was divided into two subareas based on major differences in each area's geology. A number of geological natures and the aeromagnetic anomaly values were coded systematically in each cell. The cells representing an advanced degree of exploration were chosen as control cells in each of the subareas. The geological and geophysical parameters were transformed, by means of relatively simple transformations, to produce near-normal frequency distributions. A discriminant function was then obtained by discriminant analysis to divide the control data into two groups, cells with presence of mineral occurrence and cells without mineral occurrence. the discriminant function obtained for the control area proved to be relevant both geologically and statistically. Consequently, the discriminant equation was applied to cells outside the control area. The cells were assigned to one of the two groups by entering the geologic factors pleasured from the maps into the discriminant model. The exploration potential of a large number of cells was evaluated by this procedure. To test the results, field work including geochemical sampling was carried out in the cells with highest probability of mineral occurrance The field work results have shown that the application of discriminant analysis to geological information at 1:50,000 scale with 1-km × 1-km cells combined with a careful selection of techniques for transforming the variables is a feasible method for predicting gaeralization, and as such could become a valuable tool for mining exploration.This paper was presented at Symposium 116.3, Quantitative Strategy for Exploration, held as part of the 25th International Geological Congress, Sydney, Australia, August 1976.  相似文献   
107.
108.
转录因子Sox2、Oct4、c-Myc和KLF4在iPS细胞研究中具有重要作用,将它们加入体外培养的细胞中,可以诱导体细胞去分化成为多能干细胞。作者通过RACE-PCR技术从合浦珠母贝(Pinctada fucata)的外套膜组织中克隆获得了3个转录因子——c-Myc、Sox2及KLF4的cDNA。c-Myc全长1585bp,开放阅读框的长度为1131bp,编码376个氨基酸,蛋白结构分析表明它具有保守的HLH和Myc-N结构域。Sox2全长1908bp,开放阅读框长度为990bp,编码329个氨基酸,蛋白结构分析它具有保守的HMG-box和Soxp结构域。KLF4全长2268bp,开放阅读框长624bp,编码207个氨基酸,预测该蛋白具有两个zf-H2C2_2结构域。BLAST分析它们均与太平洋牡蛎的相关蛋白具有较高同源性,说明其与太平洋牡蛎亲缘关系更近。RT-PCR实验发现这3个基因在合浦珠母贝外套膜、足、生殖腺、内脏团、闭壳肌和鳃6种组织中均有表达,表明它们是非常保守的转录因子。本研究对于合浦珠母贝细胞系建立和研究具有启发意义。  相似文献   
109.
Cathode activity plays an important role in the improvement of the microbial fuel cells on ocean floor(BMFCs). A comparison study between Rayon-based(CF-R) and PAN-based carbon fiber(CF-P) cathodes is conducted in the paper. The two carbon fibers were heat treated to improve cell performance(CF-R-H CF-P-H), and were used to build a new BMFCs structure with a foamy carbon anode. The maximum power density was 112.42 mW m-for CF-R-H, followed by 66.6 mW m-2 for CF-R, 49.7 mW m-2 for CF-P-H and 21.6 mW m-2 for CF-P respectively. The higher specific area and deep groove make CF-R have a better power output than with CF-P. Meanwhile, heat treatment of carbon fiber can improve cell power, nearly two-fold higher than heat treatment of plain fiber. This improvement may be due to the quinones group formation to accelerate the reduction of oxygen and electron transfer on the fiber surface in the three phase boundary after heat treatment. Compared to PAN-based carbon fiber, Rayon-based carbon fiber would be preferentially selected as cathode in novel BMFCs design due to its high surface area, low cost and higher power. The comparison research is significant for cathode material selection and cell design.  相似文献   
110.
For a long time, paleontologists have been focusing on hard parts of organisms during different geological periods while soft parts are rarely reported. Well-preserved plant cells, if found in fossils, are treated only as a rarity. Recent prowess in research on fossil cytoplasm indicates that plant cytoplasm not only has excellent ultrastructures preserved but also may be a quite commonly seen fossil in strata. However, up to now there is no report of plant cell fossils in China yet. Here plant cell fossils are reported from Huolinhe Coal Mine (the early Cretaceous), Inner Mongolia, China. The presence of plant cytoplasm fossils in two cones on the same specimen not only provides further support for the recently proposed hypothesis on plant cytoplasm fossilization but also marks the first record of plant cytoplasm fossils in China, which suggests a great research potential in this new area.  相似文献   
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