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51.
Noboru?KanekoEmail author Kazuhiko?Morita Tetsuya?Satoh Kimitake?Hayasaki 《Astrophysics and Space Science》2005,299(3):263-306
We study the fundamental modes of radiation hydrodynamic waves arising from one-dimensional small-amplitude initial fluctuations
with wave number k in a radiating and scattering grey medium using the Eddington approximation. The dispersion relation analyzed is the same
as that of Paper I (Kaneko et al., 2000), but is solved as a quintic in angular frequency ω while a quadratic in k
2 in Paper I. Numerical results reveal that wave patterns of five solutions are distinguished into three types of the radiation-dominated
and type 1 and type 2 matter-dominated cases. The following wave modes appear in our problem: radiation wave, conservative
radiation wave, entropy wave, Newtonian-cooling wave, opacity-damped and cooling-damped waves, constant-volume and constant-pressure
diffusion modes, adiabatic sound wave, cooling-damped and drag–force-damped isothermal sound waves, isentropic radiation-acoustic
wave, and gap mode. The radiation-dominated case is characterized by the gap between the isothermal sound and isentropic radiation-acoustic
speeds within which there is not any acoustic wave propagating with real phase speed. One of the differences between type
1 and type 2 matter-dominated cases is the connectivity of the constant-volume diffusion mode, which originates from the radiative
mode in the former case, while from the Newtonian-cooling wave in the latter case. Analytic solutions are derived for all
wave modes to discuss their physical significance. The criterion, which distinguishes between radiation-dominated and type
1 matter-dominated cases, is given by Γ0 = 9, where Γ0 = C
p
(tot)/C
V
(tot) is the ratio of total specific heats at constant pressure and constant volume. Waves in a scattering grey medium are also
analyzed, which provides us some hints for the effects of energy and momentum exchange between matter and radiation. 相似文献
52.
53.
54.
Y. Uchida S. Hirose S. Morita M. Torii T. Tanaka T. Yabiku T. Miyagoshi S. Uemura T. Yamaguchi 《Astrophysics and Space Science》1998,264(1-4):145-169
We discuss here some of the new aspects about solar flares and active regions found by the Solar X-ray Satellite Yohkoh, by
taking advantage of the wider dynamic range and higher cadence observations with higher spatial resolution compared with the
previous satellites. Those new aspects have lead us to new ways of understandings, with contradictions to the previous views
about flares and active regions that are widely conceived for a long time. We give some models that explain those newly revealed
observational results.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
55.
Cell extracts ofVibrio marinus MP-1 grown at 15°C and suspended in either tris-HCl buffer or NaCl were compared for heat lability of hexokinase, glucose phosphate isomerase, and aldolase. In tris buffer glucose phosphate isomerase and aldolase lost 50 per cent activity after one hour at low thermal exposures of 34°C and 28°C, respectively. Complete loss of enzyme activity occurred at 36°C and 34°C, respectively. Hexokinase suspended in tris buffer lost all activity above 17°C. The cell extracts suspended in 3.6 per cent NaCl were more heat stable and the enzymes lost 50 per cent activity after exposure between 31°C and 35°C. The enzymes lost all activity on thermal exposure of 33°C to 38°C in the presence of NaCl. 相似文献
56.
Vibrio marinus, an obligately psychrophilic marine bacterium, deaminated nine of 17 amino acids tested with both L-glutamine and L-serine displaying the greatest deamination rates.The L-serine deamination temperature response of washed cells depended upon the growth temperature ofV. marinus MP-1. Cells grown at 15°C displayed optimum activity at 40°C, and a shoulder at 15°C, whereas 4°C grown cells revealed two temperature optima, one at 38 and the other at 11°C, this suggests that the 4°C grown cells are physiologically different than the 15°C grown cells.It is suggested that these peaks in deamination of L-serine at different temperatures might be due to the loss of permeability control above the maximum growth temperature (20°C) of the organism.Hydrostatic pressure stimulated or suppressed L-serine deamination by washed cells depending upon the temperature at which the cells were grown and the incubation temperature of the reaction mixture. Cells grown at 15 or 4°C had deamination stimulated under pressure in the following cases: (i) cells grown at 15°C and tested for deamination at 15°C, (ii) cells grown at 4°C and tested at 4°C and (iii) cells grown at 4°C and tested at 15°C. When cells were grown at 15°C and tested at 4°C no stimulation of deamination activity due to pressure was observed. 相似文献
57.
58.
Using all available geomagnetic data, including those obtained in a detailed survey conducted by the authors in 1970, the geomagnetic anomaly pattern if the Japan Sea has been studied. It has been established that sublinear magnetic anomalies run subparallel to the general trend of the Japanese Islands. The peak to peak amplitudes of most of these anomalies are less than 300y, their wavelengths 20 to 40 km. The anomalies are much less distinct in linearity than those found in the northwestern corner of the Pacific basin off northeastern Honshu. The linear trend is better developed in the deeper basin areas and less recognizable in the Yamato- and Kitayamato-areas. The anomaly pattern appears to support the view that the Japan Sea floor evolved through a spreading process from numerous spreading centers. A definite conclusion about the genesis of the Japan Sea, however, must await further investigation. 相似文献
59.
Toshihiro Usui Seiya Nagao Masanobu Yamamoto Koji Suzuki Isao Kudo Shigeru Montani Atsushi Noda Masao Minagawa 《Marine Chemistry》2006,98(2-4):241-259
Organic carbon (C) and total nitrogen (N) contents and corresponding isotope ratios were determined in surficial sediment (0–3 cm) at 94 stations ranging from 21 to 1995 m water depth off Tokachi, Hokkaido, Japan, to elucidate the distribution and source of sedimentary organic matter. Suspended particulate organic matter (POM) in the seawater and suspended POM and sediment in the Tokachi River were also examined. δ13C, δ15N and C / N ratios of the samples in the Tokachi River suggest that the spring snowmelt is an important process for the transport of terrestrial organic matter to the coastal waters. δ13C values of suspended POM in the surface seawater were higher in May and November than in August, while δ15N values of the POM were higher in May and August than in November. These changes are attributed to seasonal changes in phytoplankton growth rate and nitrate availability. δ13C and δ15N values in the sediments off Tokachi were lowest near the Tokachi River mouth, and increased offshore to constant values that persisted from 134 to 1995 m water depth. The spatial variation in C / N ratios in the sediment mirrored those of δ13C and δ15N. Comparison of δ13C, δ15N and C / N ratios in the sediments off Tokachi with those in the Tokachi River and seawater indicates that about half of the organic matter in the sediment was of terrestrial origin near the Tokachi River mouth, and the sedimentary organic matter from 134 to 1995 m water depth was of marine origin. The organic C content in the sediment was high near the Tokachi River mouth, and also around 1000 m water depth. The C content was significantly correlated with silt plus clay content, with different regression lines for those stations shallower and deeper than 134 m, owing to several stations of higher C content with the elevated C / N ratio on the inner shelf. These results suggest that transport and deposition of organic-rich fine sediment particles by hydrodynamic processes were major factors controlling C content off Tokachi. In addition, the supply of a fraction of terrestrial organic matter with high C / N probably also affected C content on the inner shelf. 相似文献
60.
A large-scale collision at a plate boundary is expected to play an important role not only in the deformation at the boundary but also in the motion of the plate carrying the buoyant material to be accreted. Possible changes in rates and directions of such motions may be calculated provided that certain assumptions are made about the nature of the driving forces. In this model we shall assume basically that:
- 1. (1) an oceanic plate is driven by slab pull and ridge push, being resisted by basal asthenospheric drag and slab resistance; and
- 2. (2) because of detachment, slab pull is lost upon collision.