全文获取类型
收费全文 | 81篇 |
免费 | 2篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 17篇 |
地球物理 | 17篇 |
地质学 | 34篇 |
海洋学 | 7篇 |
天文学 | 5篇 |
自然地理 | 1篇 |
出版年
2020年 | 3篇 |
2019年 | 1篇 |
2018年 | 1篇 |
2017年 | 3篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2013年 | 2篇 |
2012年 | 3篇 |
2011年 | 4篇 |
2010年 | 7篇 |
2009年 | 3篇 |
2008年 | 6篇 |
2007年 | 5篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 3篇 |
2002年 | 2篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 1篇 |
1993年 | 1篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1981年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
排序方式: 共有84条查询结果,搜索用时 312 毫秒
71.
We examine 800-year time series of internally generated variability in both a coupled ocean-atmosphere model where water
vapor anomalies are not allowed to interact with longwave radiation and one where they are. The ENSO-like phenomenon in the
experiment without water vapor feedback is drastically suppressed both in amplitude and geographic extent relative to the
experiment with water vapor feedback. Surprisingly, the reduced amplitude of ENSO-related sea surface temperature anomalies
in the model without water vapor feedback cannot be attributed to greater longwave damping of sea surface temperature. (Differences
between the two experiments in radiative feedback due to clouds counterbalance almost perfectly the differences in radiative
feedback due to water vapor.) Rather, the interaction between water vapor anomalies and longwave radiation affects the ENSO-like
phenomenon through its influence on the vertical structure of radiative heating: Because of the changes in water vapor associated
with it, a given warm equatorial Pacific sea surface temperature anomaly is associated with a radiative heating profile that
is much more gravitationally unstable when water vapor feedback is present. The warm sea surface temperature anomaly therefore
results in more convection in the experiment with water vapor feedback. The increased convection, in turn, is related to a
larger westerly wind-stress anomaly, which creates a larger decrease in upwelling of cold water, thereby enhancing the magnitude
of the original warm sea surface temperature anomaly. In this manner, the interaction between water vapor anomalies and longwave
radiation magnifies the air-sea interactions at the heart of the ENSO phenomenon; without this interaction, the coupling between
sea surface temperature and wind stress is effectively reduced, resulting in smaller amplitude ENSO episodes with a more limited
geographical extent.
Received: 26 March 1999 / Accepted: 25 October 1999 相似文献
72.
Mina Yutani Takehiko Yagi Hitoshi Yusa Tetsuo Irifune 《Physics and Chemistry of Minerals》1997,24(5):340-344
In situ X-ray diffraction experiments of calcium ferrite-type MgAl2O4 have been carried out using a diamond anvil cell combined with synchrotron radiation and an imaging plate X-ray detector
under hydrostatic pressures up to 9 GPa. The observed unit-cell volumes at various pressures were fitted to the Birch-Murnaghan
equation of state, yielding a bulk modulus of K
T
0= 241(3) GPa when K′
T
0=4 is assumed. This relatively large bulk modulus of calcium ferrite-type MgAl2O4 is consistent with that expected from the systematic relation between bulk modulus and molar volume for the most compounds
possessing fcc oxygen packing.
Received March 5, 1996/Revised, accepted October 15, 1996 相似文献
73.
Extinction measurements were made for three kinds of amorphous carbon grains in the range 2100 -340 m. Absolute values of extinction coefficients from different sources vary by almost constant factors. Wavelength dependences of extinction curves show a –1 or less steep fall off, against a –2 or steeper fall off of graphite grains. Small humps are found around 6.3, 8, 13.3 and 90 m, although their origins are not yet clear. The infrared properties of amorphous carbon grains suggest that they could supply a significant amount of far-infrared emission noted in recent astronomical observations. 相似文献
74.
Takehiko Hiraga Osamu Nishikawa Toshiro Nagase Mizuhiko Akizuki David L. Kohlstedt 《Contributions to Mineralogy and Petrology》2002,143(6):664-672
Interfacial energies of quartz/quartz (qz/qz), albite/albite (ab/ab), and quartz/albite (qz/ab) boundaries in low-grade pelitic schist were determined based on measured values of dihedral angles. Three kinds of microstructures were investigated, and the interfacial energies were obtained in two independent ways. (1) Relative values of interfacial energy were calculated from dihedral angles formed at quartz and albite triple junctions. (2) Subgrain boundary energy was calculated using the Read-Shockley theory for a boundary connected to an intergranular pore. Dihedral angles formed at the corners of intergranular pores were measured. From the interfacial tension balance equation, the value of the qz/qz grain boundary energy was then obtained. (3) Dihedral angles formed at intersections of either pericline or albite twin boundaries with either ab/ab or qz/ab boundaries were measured. The twin boundary energy was calculated based on a previously derived equation using Landau potential, twin wall thickness, and critical temperature for a phase transition in albite. With a modified interfacial tension balance equation for a twin boundary fixed to a facet orientation, the interfacial energies of ab/ab and qz/ab boundaries were obtained. Energies obtained by methods of (2) and (3) are in good agreement. The interfacial energies for qz/qz, ab/ab, and qz/ab boundaries obtained in this study are 270뀶, 300끞, and 250끀 mJ/m2, respectively. 相似文献
75.
76.
The electrical conductivity of three polymorphs of Mn2GeO4 was measured under high pressures in the temperature range of 300–1200 K. It was found that the electrical conductivity increases discontinuously due to the transformation both from olivine structure (α) to modified spinel structure (β) and from β to strontium plumbate structure (δ). The amount of discontinuous change is about one half order of magnitude from α to β and one third order of magnitude from β to δ at 1200 K. In order to see the effect of the presence of iron ions, the electrical conductivity of the solid solution of (Mn0.9Fe0.1)2GeO4 was also measured. It was found that at low temperatures, where impurity conduction may be dominant, the solid solution is more conductive than the pure Mn2GeO4, but at high temperature no significant differences were observed between the solid solution and pure Mn2GeO4 in all polymorphs.A phase transformation from modified spinel structure to strontium plumbate structure is considered to be one of the plausible transformations occurring at a depth around 650 km in the earth's mantle. These experiments suggest that if this kind of transformation occurs in the mantle, some degrees of discontinuous change in electrical conductivity may be expected around 650 km. 相似文献
77.
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
78.
79.
Crude oil bioremediation field experiment in the Sea of Japan 总被引:4,自引:0,他引:4
Maki H Hirayama N Hiwatari T Kohata K Uchiyama H Watanabe M Yamasaki F Furuki M 《Marine pollution bulletin》2003,47(1-6):74-77
Experimental bioremediation of crude oil was conducted for approximately 3 months in the intertidal zone of the Sea of Japan, Hyogo Prefecture. Artificial mixtures of weathered Arabian light crude oil and sand taken from the experimental site were wrapped in polyester net envelopes. The envelopes were placed in drum-shaped acrylic vessels with perforated sides to facilitate seawater exchange. The vessels were laid in the intertidal area. Slow release nitrogen and phosphorus synthetic fertilizer granules were added to the oil-sand mixtures in three different amounts. Some oil-sand mixtures were unfertilized controls. The oil-sand mixtures were periodically sampled and changes in the composition of the residual oils were monitored. Oil samples were subjected to gas chromatography coupled with mass spectrometry for analysis of some representative semi-volatile aliphatic and aromatic compounds. All values for each analyte were normalized against that of hopane to evaluate the extent of oil biodegradation. Significant increases in the concentrations of both nitrogen and phosphorus were found in the fertilized sections in accordance with the amounts of added fertilizers. Although significant natural attenuation of oil was observed in the unfertilized sections, fertilization stimulated the degradation rate of the oil in the early stage of the experimental term. The extent of the oil biodegradation increased as the amount of added fertilizer increased. However, the final degradation efficiencies for each oil component in the fertilized sections were not significantly different from those in the unfertilized sections, and the degradation of each oil component had almost ceased after 6 weeks. We conclude that excessive amounts of macronutrients are required to accelerate oil biodegradation and that fertilization is only effective in the early stages. 相似文献
80.
Takehiko Aso 《Planetary and Space Science》1974,22(4):583-594
A low frequency impedance probe designed to detect the ion-electron hybrid resonance in the ionospheric plasma is studied. Firstly, the effect of finite resistance of an ion sheath surrounding a probe is analyzed for the case of a cylindrical probe and quantitative insight into this is given. Secondly, the dissipations due to warm plasma effects which appear in the actual experiment flown aboard a space vehicle are discussed. These depend upon the dimensions of the probe system and the velocity of the system relative to the mean thermal velocity of charged particles. Analyses are then carried out for a simple planar grid model using electrostatic and hydrodynamic approximations. 相似文献