全文获取类型
收费全文 | 103篇 |
免费 | 8篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 3篇 |
地球物理 | 23篇 |
地质学 | 20篇 |
海洋学 | 23篇 |
天文学 | 31篇 |
综合类 | 1篇 |
自然地理 | 9篇 |
出版年
2019年 | 1篇 |
2018年 | 3篇 |
2017年 | 3篇 |
2016年 | 6篇 |
2015年 | 1篇 |
2014年 | 3篇 |
2013年 | 5篇 |
2012年 | 9篇 |
2011年 | 6篇 |
2010年 | 2篇 |
2009年 | 4篇 |
2008年 | 6篇 |
2007年 | 4篇 |
2006年 | 2篇 |
2005年 | 6篇 |
2004年 | 6篇 |
2003年 | 6篇 |
2002年 | 5篇 |
2001年 | 1篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1994年 | 2篇 |
1993年 | 6篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1986年 | 2篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1975年 | 1篇 |
排序方式: 共有111条查询结果,搜索用时 15 毫秒
101.
Munetake Sasaki Koichiro Fujimoto Hitoshi Tsukamoto Takayuki Sawaki Masakatsu Sasada Masanori Kurosawa Masahiko Yagi Yoichi Muramatsu Osamu Kato + Ryo Komatsu + Kaichiro Kasai + Nobuo Doi+ 《Resource Geology》2003,53(2):127-142
Abstract. Cathodoluminescence (CL) color, rare earth element (REE) content, sulfur and oxygen isotopes and fluid inclusions of anhydrite, which frequently filled in hydrothermal veins in the Kakkonda geothermal system, were investigated to elucidate the spatial, temporal and genetical evolution of fluids in the deep reservoir. The anhydrite samples studied are classified into four types based on CL colors and REE contents: type-N (no color), type-G (green color), type-T (tan color) and type-S (tan color with a high REE content). In the shallow reservoir, only type-N anhydrite is observed. In the deep reservoir, type-G anhydrite occurs in vertical veins whereas type-T and -N in lateral veins. Type-S anhydrite occurs in the heat-source Kakkonda Granite. The CL textures revealed that type-G anhydrite deposited earlier than type-T in the deep reservoir, implying that fracture system was changed from predominantly vertical to lateral.
Studies of fluid inclusions and δ34 S and δ18 O values of the samples indicate that type-N anhydrite deposited from diluted fluids derived from meteoric water, whereas type-G, -T and -S anhydrites deposited from magmatic brines derived from the Kakkonda Granite with the exception of some of type-G with recrystallization texture and no primary fluid inclusion, which deposited from fossil seawater preserved in the sedimentary rocks. Type-G, -T and -S anhydrites exhibit remarkably different chondrite-normalized REE patterns with a positive Eu anomaly, with a convex shape (peak at Sm or Eu) and with a negative Eu anomaly, respectively. The difference in the patterns might result from the different extent of hydrothermal alteration of the reservoir rocks and contribution of the magmatic fluids. 相似文献
Studies of fluid inclusions and δ
102.
Masaharu Watanabe Yasunobu Iwasaka Takashi Shibata Masahiko Hayashi Motowo Fujiwara Roland Neuber 《Atmospheric Research》2004,69(3-4):199-215
Balloon-borne aerosol measurements were performed with an optical particle counter between 1994 and 2000 at Ny-Ålesund (79°N), Svarbard. Throughout the observation period, continuous decay was found in the concentrations of particles with 0.4–0.6 μm in radius in the Arctic stratosphere, suggesting that Pinatubo aerosols remained even at the end of the 1990s. The decay rate was clearly higher for larger particle sizes, and higher at higher altitude (e-folding time of 970–526 days), suggesting a gravitational sedimentation effect. For smaller particles with R<0.4 μm, slight increases in concentration with time were found, which agreed with the measurements at mid-latitude. The sulfate mass mixing ratio in the Arctic stratosphere before 1998 showed values higher than those at middle latitude, while values were almost the same in both regions after 1998. A possible explanation of the latitudinal difference is a time lag (of 0.5–1 year) in the arrival of Pinatubo aerosols in the Arctic. 相似文献
103.
Kenya Ohgushi Yoshitaka Matsushita Nobuyoshi Miyajima Yoshio Katsuya Masahiko Tanaka Fujio Izumi Hirotada Gotou Yutaka Ueda Takehiko Yagi 《Physics and Chemistry of Minerals》2008,35(4):189-195
Structural, morphological, magnetic, and thermal properties have been investigated for a novel post-perovskite oxide CaPtO3 synthesized under high pressure. By comparing obtained structural parameters with those for known post-perovskite compounds,
we argue that the chemical bond has a strong covalent character. Precise measurements of the Langevin susceptibility χ
0
= −9.6 × 10−5 emu/mol and Debye temperature θ ∼ 470 K provide a good opportunity to confirm the reliability of first-principle calculations on predicting physical properties
of the Earth’s D” layer. 相似文献
104.
Rónadh COX Lissa C. F. ONG Masahiko ARAKAWA Kate C. SCHEIDER 《Meteoritics & planetary science》2008,43(12):2027-2048
Abstract— Ice thickness estimates and impactor dynamics indicate that some impacts must breach Europa's ice crust; and outcomes of impact experiments using ice‐over‐water targets range from simple craters to chaos‐like destroyed zones, depending on impact energy and ice competence. First‐order impacts‐into thick ice or at low impact energy‐produce craters. Second‐order impacts punch through the ice, making holes that resemble raft‐free chaos areas. Third‐order impacts‐into thinnest ice or at highest energy‐produce large irregular raft‐filled zones similar to platy chaos. Other evidence for an impact origin for chaos areas comes from the size‐frequency distribution of chaos+craters on Europa, which matches the impact production functions of Ganymede and Callisto; and from small craters around the large chaos area Thera Macula, which decrease in average size and density per unit area as a function of distance from Thera's center. There are no tiny chaos areas and no craters >50 km diameter. This suggests that small impactors never penetrate, whereas large ones (ÜberPenetrators: >2.5 km diameter at average impact velocity) always do. Existence of both craters and chaos areas in the size range 2–40 km diameter points to spatial/temporal variation in crust thickness. But in this size range, craters are progressively outnumbered by chaos areas at larger diameters, suggesting that probability of penetration increases with increasing scale of impact. If chaos areas do represent impact sites, then Europa's surface is older than previously thought. The recalculated resurfacing age is 480 (‐302/+960) Ma: greater than prior estimates, but still very young by solar system standards. 相似文献
105.
A polychaete, Capitella sp. I has been shown to degrade organics actively in organically enriched sediment below fish farms. Our aim of the present study is to enhance the biological treatment of sediment by co-inoculation of Capitella sp. I with bacterial isolates that possess high degrading potential for organic matter. We isolated a total of 200 bacterial strains from fecal pellets, burrow lining, worm body, and sediment, and selected six of them for the degradation experiments in the sediment microcosms. With two out of the six isolates, tentatively identified as Vibrio sp. and Vibrio cyclitrophicus by 16SrDNA sequence, we found the TOC reduction rate was stimulated in sediment co-inoculated with the worms and each of the bacteria. In contrast, this was not observed in sediments inoculated only with the worms or the bacterium. These results strongly suggest that co-inoculation of Capitella sp. I with bacteria improves biodegradation. 相似文献
106.
Yamada M Takada H Toyoda K Yoshida A Shibata A Nomura H Wada M Nishimura M Okamoto K Ohwada K 《Marine pollution bulletin》2003,47(1-6):105-113
Polycyclic Aromatic Hydrocarbons (PAHs) are one of the components found in oil and are of interest because some are toxic. We studied the environmental fate of PAHs and the effects of chemical dispersants using experimental 500 l mesocosm tanks that mimic natural ecosystems. The tanks were filled with seawater spiked with the water-soluble fraction of heavy residual oil. Water samples and settling particles in the tanks were collected periodically and 38 PAH compounds were analyzed by gas chromatography-mass spectrometry (GC-MS). Low molecular weight (LMW) PAHs with less than three benzene rings disappeared rapidly, mostly within 2 days. On the other hand, high molecular weight (HMW) PAHs with more than four benzene rings remained in the water column for a longer time, up to 9 days. Also, significant portions (10-94%) of HMW PAHs settled to the bottom and were caught in the sediment trap. The addition of chemical dispersant accelerated dissolution and biodegradation of PAHs, especially HMW PAHs. The dispersant amplified the amounts of PAHs found in the water column. The amplification was the greater for the more hydrophobic PAHs, with an enrichment factor of up to six times. The increased PAHs resulting from dispersant use overwhelmed the normal degradation and, as a result, higher concentrations of PAHs were observed in water column throughout the experimental period. We conclude that the addition of the dispersant could increase the concentration of water column PAHs and thus increase the exposure and potential toxicity for organisms in the natural environment. By making more hydrocarbon material available to the water column, the application of dispersant reduced the settling of PAHs. For the tank with dispersant, only 6% of chrysene initially introduced was detected in the sediment trap whereas 70% was found in the trap in the tank without dispersant. 相似文献
107.
108.
109.
110.
To estimate the spatial distribution of groundwater discharge from the bottom of a small lake of Kumamoto in Japan, we applied continuous radon measurements with a dual loop system and verified the results obtained using the radon method by visual diving surveys. Time‐shifting correction in the dual‐loop system is reasonable to obtain the true radon activity in water. Distributions of radon activity and water temperature in the study area reveal the effects on groundwater discharge and mixing situation of lake water. The estimated discharge zone ascertained using the radon method agrees with the groundwater discharge distribution observed through diving surveys. Although the data resolution of the radon method is much greater than the width of observed discharge zones, the general distribution of groundwater discharge is recognizable. The dual loop system of radon measurement is useful for smaller areas. 相似文献