全文获取类型
收费全文 | 146篇 |
免费 | 4篇 |
国内免费 | 2篇 |
专业分类
大气科学 | 8篇 |
地球物理 | 34篇 |
地质学 | 42篇 |
海洋学 | 39篇 |
天文学 | 22篇 |
自然地理 | 7篇 |
出版年
2024年 | 1篇 |
2021年 | 4篇 |
2020年 | 1篇 |
2019年 | 2篇 |
2018年 | 1篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 7篇 |
2012年 | 3篇 |
2011年 | 2篇 |
2010年 | 15篇 |
2009年 | 14篇 |
2008年 | 5篇 |
2007年 | 11篇 |
2006年 | 10篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2002年 | 2篇 |
2001年 | 2篇 |
2000年 | 2篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 1篇 |
1995年 | 2篇 |
1994年 | 7篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1984年 | 3篇 |
1983年 | 1篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有152条查询结果,搜索用时 31 毫秒
121.
Takuya Hasegawa Kentaro Ando Keisuke Mizuno Roger Lukas Bunmei Taguchi Hideharu Sasaki 《Ocean Dynamics》2010,60(5):1255-1269
We investigate the relationship between sea surface temperature (SST) cooling and upwelling along Papua New Guinea’s (PNG) north coast before the onset of El Niño events using a hindcast experiment with a high-resolution ocean general circulation model. Coastal upwelling and related SST cooling appear along PNG north coast during the boreal winter before the onsets of six El Niño events occurring during 1981–2005. Relatively cool SSTs appear along PNG north coast during that time, when anomalous northwesterly surface wind stress, which can cause coastal upwelling by offshore Ekman transport appearing over the region. In addition, anomalous cooling tendencies of SST are observed, accompanying anomalous upward velocities at the base of the mixed layer and shallow anomalies of 27°C isotherm depth. It is also shown that entrainment cooling plays an important role in the cooling of the mixed layer temperature in this region. 相似文献
122.
Charles W. Mandeville Akira Sasaki Genji Saito Kevin Faure Robert King Erik Hauri 《Earth and Planetary Science Letters》1998,160(3-4):709-722
We present the first sulfur and oxygen isotopic data for tephra from the catastrophic 1883 eruption of Krakatau. Sulfur isotopic ratios in unaltered Krakatau tephra erupted August 26–27, 1883 are markedly enriched in 34S relative to mantle sulfur. High δ34S values of +6.3 to +16.4‰ can best be explained by open-system or multi-stage degassing of SO2 from the oxidized rhyodacitic and gray dacitic magmas with 34S enrichment of SO2−4 remaining in the melt. Lower whole-rock δ34S values of +2.6‰ and +4.0‰ in two oxidized gray dacitic samples indicate more primitive subarc mantle sulfur in the 1883 magma chamber. Initial δ34S of the rhyodacitic magma was probably in the +1.5‰ to +4.0‰ range and similar to δ34S values measured in arc volcanic rocks from the Mariana Arc. 相似文献
123.
124.
Koichi Sakakibara Maki Tsujimura Sho Iwagami Yutaro Sato Kosuke Nagano Yuichi Onda 《水文研究》2019,33(6):892-904
Understanding rainfall‐runoff processes is crucial for prevention and prediction of water‐related natural disasters. Sulfur hexafluoride (SF6) is a potential tracer, but few researches have applied it for rainfall‐runoff process studies. We observed multiple tracers including SF6 in spring water at 1‐ to 2‐hr intervals during rainstorm events to investigate the effectivity of SF6 tracer in rainfall–runoff studies through the clarification of rainfall–runoff process. The target spring is a perennial spring in a forested headwater catchment with an area of 0.045 km2 in Fukushima, Japan. The relationship between the SF6 concentration in spring water and the spring discharge volume was negative trend; the SF6 concentration in spring water becomes low as the spring discharge volume increases especially during rainstorms. The hydrograph separation using SF6 and chloride ion tracers was applied for determining the contribution of principal sources on rainfall–runoff water. It suggested more than 60% contribution of bedrock groundwater at the rainfall peak and high percentage contribution continued even in the hydrograph recession phase. Based on observed low SF6 concentration in groundwater after heavy rainfall, the replacement of groundwater near the spring with bedrock groundwater is indicated as a mechanism for water discharge with low SF6 concentration during rainfall events. Consequently, rainstorm events play an important role as triggers in discharging water stored in the deeper subsurface area. In addition, SF6 tracer is concluded as one of the strongest tracers for examining rainfall–runoff process studies. And, therefore, this study provided new insights into the dynamics of groundwater and its responses to rainfall in terms of SF6 concentration variance in water in headwater regions. 相似文献
125.
Chemical reactions and volatile supply through hypervelocity impacts may have played a key role for the origin and evolution of both planetary and satellite atmospheres. In this study, we evaluate the role of impact-induced N2 production from reduced nitrogen-bearing solids proposed to be contained in Titan’s crust, ammonium sulfate ((NH4)2SO4), for the replenishment of N2 to the atmosphere in Titan’s history. To investigate the conversion of (NH4)2SO4 into N2 by hypervelocity impacts, we measured gases released from (NH4)2SO4 that was exposed to hypervelocity impacts created by a laser gun. The sensitivity and accuracy of the measurements were enhanced by using an isotope labeling technique for the target. We obtained the efficiency of N2 production from (NH4)2SO4 as a function of peak shock pressure ranging from ∼8 to ∼45 GPa. Our results indicate that the initial and complete shock pressures for N2 degassing from (NH4)2SO4 are ∼10 and ∼25 GPa, respectively. These results suggest that cometary impacts on Titan (i.e., impact velocity vi > ∼8 km/s) produce N2 efficiently; whereas satellitesimal impacts during the accretion (i.e., vi < 4 km/s) produce N2 only inefficiently. Even when using the proposed small amount of (NH4)2SO4 content in the crust (∼4 wt.%) (Fortes, A.D. et al., 2007. Icarus 188, 139-153), the total amount of N2 provided through cometary impacts over 4.5 Ga reaches ∼2-6 times the present atmospheric N2 (i.e., ∼7 × 1020-2 × 1021 [mol]) based on the measured production efficiency and results of a hydrodynamic simulation of cometary impacts onto Titan. This implies that cometary impacts onto Titan’s crust have the potential to account for a large part of the present N2 through the atmospheric replenishment after the accretion. 相似文献
126.
Aya Sakaguchi Masayoshi Yamamoto Junpei Tomita Kenta Mino Keiichi Sasaki Kenji Kashiwaya Takayoshi Kawai 《Quaternary International》2009,205(1-2):65
Uranium and thorium isotopes in an 81-m long sediment core (HDP-04) of Lake Hovsgol, Mongolia, were measured to investigate their downcore distributions and to explore potential linkage to paleoenvironmental changes. Three-dimensional isochron techniques using isotope-ratio diagrams in 238U–234U–230Th–232Th system presented by Ludwig and Titterington were applied to age date the lake sediments at the depths of 11.42, 14.71 and 14.83 m in the HDP-04 section, the estimated ages of these horizons are 66 ± 8, 122 ± 11 and 128 ± 22 ka, respectively. The 238U concentration throughout the entire section fluctuated by a factor of 12, ranging from 19.9 to 232.1 mBq/g with anomalously high 238U peak at 23.8 m in depth, while the 232Th concentration varied only by a factor of about two between 24.3 and 54.0 mBq/g. The discrimination of the bulk 238U into authigenic and terrigenous 238U fractions was attempted, based on the measured 232Th as a correction index for terrigenous materials. In the upper 24 m corresponding to the last 250 ka, the authigenic 238U was higher in interglacials and lower in glacials. This depth profile of authigenic 238U contents was almost identical pattern with that found in a sediment core (VER98-1-6) from the Academician Ridge, Lake Baikal. Further, this profile can be correlated well with that of photosynthetic pigment contents, one of proxies of paleoproductivity, suggesting that the variation of authigenic 238U contents were associated with the environmental change around Lake Hovsgol. 相似文献
127.
Characterization of drying-induced deformation behaviour of Opalinus Clay and tuff in no-stress regime 总被引:1,自引:0,他引:1
Aung Ko Ko Soe Masahiko Osada Manabu Takahashi Tai Sasaki 《Environmental Geology》2009,58(6):1215-1225
The drying-induced deformation behaviour of Opalinus Clay and tuff, which are being investigated under international and local
collaborative projects for nuclear waste disposal in Switzerland and Japan, was investigated under a no-stress condition in
the laboratory to evaluate their generic susceptibility to the formation of excavation damaged zone. The cylindrical core
samples of Opalinus Clay and tuff were prepared to a one-dimensional drying condition and submitted to an uncontrolled laboratory
environment. The strain evolution, evaporative water loss and environmental entities, such as temperature and relative humidity,
were recorded simultaneously and quasi-continuously. It was observed that the drying phase induced significant strain magnitude
and damage in Opalinus Clay samples, which was evidenced by the formation of hairy cracks on the surface parallel to the bedding.
On the contrary, the strain occurrences in tuff samples were relatively insignificant, and no tendency of cracking was observed.
In addition, the quasi-continuous availability of volumetric strains was further used in poroelastic relation for the estimation
of capillary suction evolution. The calculated results were validated with pore size distributions obtained from mercury intrusion
porosimetry. 相似文献
128.
Akihiko Murata Hidetaka Sasaki Mizuki Hanafusa Kazuo Kurihara 《Theoretical and Applied Climatology》2013,112(1-2):351-361
This study demonstrates that urban heat island (UHI) intensity can be estimated by comparing observational data and the outputs of a well-developed high-resolution regional climate model. Such an estimate is possible because the observations include the effects of UHI, whereas the model used does not include urban effects. Therefore, the errors in the simulated surface air temperature, defined as the difference between simulated and observed temperatures (simulated minus observed), are negative in urban areas but 0 in rural areas. UHI intensity is estimated by calculating the difference in temperature error between urban and rural areas. Our results indicate that overall UHI intensity in Japan is 1.5 K and that the intensity is greater in nighttime than in daytime, consistent with the previous studies. This study also shows that root mean square error and the magnitude of systematic error for the annual mean temperature are small (within 1.0 K). 相似文献
129.
Sulfur isotopic characteristics of late Cenozoic ore deposits at the arc junction of Hokkaido, Japan
Abstract Sulfide minerals of late Cenozoic vein-type deposits of southwest Hokkaido and Kuril Islands yielded δ34 CDT S values of 2 to 8 permil, which are typical green-tuff values of magnetite-series igneous terrane. Sulfides of the Kitami district of northeast Hokkaido, on the other hand, are characterized by negative δ34 SCDT values, ranging from 0 to - 7 permil. This unique value among ore deposits in the late Cenozoic back-arc terranes in the Japanese Islands is considered to have resulted from extraction of 32 S enriched sulfur from the basement rocks, because of well-developed N-S fracturing in the basement, which is characteristic of the axial belt and Kitami district of Hokkaido. 相似文献
130.
Yu. V. Barkin H. Hanada K. Matsumoto S. Sasaki M. Yu. Barkin 《Solar System Research》2014,48(6):403-419
An analytical theory of lunar physical librations based on its two-layer model consisting of a non-spherical solid mantle and ellipsoidal liquid core is developed. The Moon moves on a high-precision orbit in the gravitational field of the Earth and other celestial bodies. The defined fourth mode of a free libration is caused by the influence of the liquid core, with a long period of 205.7 yr, with amplitude S = 0″0395 and with an initial phase Π0 = ?134° (for the initial epoch 2000.0). Estimates of dynamic (meridional) oblatenesses of a liquid core of the Moon have been estimated: ?D = 4.42 × 10?4, μD = 2.83 × 10?4 (?D + μD = 7.24 × 10?4). These results have been obtained as a result of comparison of the developed analytical theory of physical librations of the Moon with the empirical theory of librations of the Moon constructed on the basis of laser observations. 相似文献