全文获取类型
收费全文 | 343篇 |
免费 | 10篇 |
国内免费 | 8篇 |
专业分类
测绘学 | 3篇 |
大气科学 | 13篇 |
地球物理 | 111篇 |
地质学 | 92篇 |
海洋学 | 74篇 |
天文学 | 47篇 |
综合类 | 1篇 |
自然地理 | 20篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2019年 | 8篇 |
2018年 | 4篇 |
2017年 | 8篇 |
2016年 | 11篇 |
2015年 | 15篇 |
2014年 | 12篇 |
2013年 | 20篇 |
2012年 | 11篇 |
2011年 | 16篇 |
2010年 | 21篇 |
2009年 | 21篇 |
2008年 | 17篇 |
2007年 | 20篇 |
2006年 | 24篇 |
2005年 | 12篇 |
2004年 | 15篇 |
2003年 | 6篇 |
2002年 | 8篇 |
2001年 | 9篇 |
2000年 | 13篇 |
1999年 | 6篇 |
1998年 | 4篇 |
1997年 | 3篇 |
1996年 | 4篇 |
1995年 | 10篇 |
1994年 | 6篇 |
1993年 | 5篇 |
1992年 | 4篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 5篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 6篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1981年 | 1篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
排序方式: 共有361条查询结果,搜索用时 437 毫秒
61.
The general-relativistic equations of hydrodynamics for a nonideal fluid are derived in the modified Lagrangian form. Together with the zeroth and first moment equations of radiative transfer derived by Morita and Kaneko (1986), the equations provide a complete set of the modified Lagrangian equations of radiation hydrodynamics. The equations of hydrodynamics are specialized for a thermally conducting, Newtonian viscous fluid in the modified Lagrangian form, which are the generalization of the specialrelativistic equations of hydrodynamics derived by Greenberg (1975). 相似文献
62.
Morphological characteristics of snow ripples formed by drifting snow were investigated as functions of wind velocity in a cold wind tunnel at -15 °C. Wave-length, wave height and migration rate of snow ripples increased from 5 to 20 cm, 3 to 5 mm and 1 to 8 cm/min, respectively, with increasing wind velocity from 5 to 7 m/s. Measured size distributions of snow particles in snow ripples showed sorting of large particles in ridges, suggesting that the snow ripple migration is caused by creeping of large particles. The snow drift rate caused by creep, that is, by the ripple migration, was estimated to amount, at least, to 6% of the total snow drift rate. 相似文献
63.
Use of tsunami waveforms for earthquake source study 总被引:1,自引:0,他引:1
Tsunami waveforms recorded on tide gauges, like seismic waves recorded on seismograms, can be used to study earthquake source processes. The tsunami propagation can be accurately evaluated, since bathymetry is much better known than seismic velocity structure in the Earth. Using waveform inversion techniques, we can estimate the spatial distribution of coseismic slip on the fault plane from tsunami waveforms. This method has been applied to several earthquakes around Japan. Two recent earthquakes, the 1968 Tokachi-oki and 1983 Japan Sea earthquakes, are examined for calibration purposes. Both events show nonuniform slip distributions very similar to those obtained from seismic wave analyses. The use of tsunami waveforms is more useful for the study of unusual or old earthquakes. The 1984 Torishima earthquake caused unusually large tsunamis for its earthquake size. Waveform modeling of this event shows that part of the abnormal size of this tsunami is due to the propagation effect along the shallow ridge system. For old earthquakes, many tide gauge records exist with quality comparable to modern records, while there are only a few good quality seismic records. The 1944 Tonankai and 1946 Nankaido earthquakes are examined as examples of old events, and slip distributions are obtained. Such estimates are possible only using tsunami records. Since tide-gauge records are available as far back as the 1850s, use of them will provide unique and important information on long-term global seismicity. 相似文献
64.
The correlation of whistler occurrence rate at a low latitude with thunderstorm activity at its conjugate region and with solar activity 总被引:1,自引:0,他引:1
The correlations of occurrence rate of whistlers in January during one solar cycle (1977–1987) at a low latitude station (Yamaoka, geomag. lat. 25°, L=1.26) with thunderstorm activity near its conjugate region and also with solar activity have been investigated, and it is found that the occurrence rate has no correlation with the lightning flashes near the conjugate point, while it is negatively correlated with solar activity. On the basis of these findings it is suggested that the ionospheric absorption is of major importance in the long-term variation of whistler occurrence rate, with the duct formation being of secondary effect, while the lightning activity is only a necessary condition for whistler occurrence. 相似文献
65.
Wave normal directions of VLF signals propagating through the ionosphere can be determined by measuring Doppler frequency shift of the signals by means of rocket borne receivers. Two rockets were launched to detect the NWC signal of 22.3 kHz which was transmitted from Australia and propagated on two completely different paths, one being propagated through the Earth-ionosphere waveguide and up to the rocket, the other propagated down to the rocket by the whistler mode directly from the source in the opposite hemisphere. The wave normal directions of the latter mode were almost vertically downward in the ionosphere in the northern hemisphere, although substantial error was involved in the determination of the wave normal direction for a part of the upgoing flight of the rockets, due to the relative geometry of the directions of the rocket flight and the geomagnetic field. The effect of the horizontal gradients of the ionosphere on the above results were found to be not significant. From the experimental results it is concluded that field aligned ducts stretching down to the rocket altitudes did not exist, at least, during the rocket flights. 相似文献
66.
Peter G. Brewer Edward Peltzer Izuo Aya Peter Haugan Richard Bellerby Kenji Yamane Ryuji Kojima Peter Walz Yasuharu Nakajima 《Journal of Oceanography》2004,60(4):751-758
We have carried out a small-scale (∼20 l) CO2 sequestration experiment off northern California (684 m depth, ∼5°C, background ocean pH ∼7.7) designed as an initial investigation
of the effects of physical forcing of the fluid, and the problem of sensing the formation of a low pH plume. The buoyant CO2 was contained in a square frame 1.2 m high, exposing 0.21 m2 to ocean flow. Two pH electrodes attached to the frame recorded the signal; a second frame placed 1.9 m south of the CO2 pool was also equipped with two recording pH electrodes. An additional pH electrode was held in the ROV robotic arm to probe
the fluid interface. Local water velocities of up to 40 cm sec−1 were encountered, creating significant eddies within the CO2 box, and forcing wavelets at the fluid interface. This resulted in rapid CO2 dissolution, with all CO2 being depleted in a little more than 2 days. The pH record from the sensor closest (∼10 cm) to the CO2 showed many spikes of low pH water, the extreme value being ∼5.9. The sensor 1 m immediately below this showed no detectable
response. The electrodes placed 1.9 m distant from the source also recorded very small perturbations. The results provide
important clues for the design of future experiments for CO2 disposal and biogeochemical impact studies. These include the need for dealing with the slow CO2 hydration kinetics, better understanding of the fluid dynamics of the CO2-water interface, and non-point source release designs to provide more constant, controlled local CO2 enrichments within the experimental area.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
67.
Yoshinobu Wakata Takashi Setou Ikuo Kaneko Hiroshi Uchida Shiro Imawaki 《Journal of Oceanography》2006,62(1):25-35
The interannual variability of the Kuroshio volume transport passing through the 137°E meridian south of Japan was simulated
with an ocean general circulation model (OGCM). The time series of the Kuroshio volume transport over the 1000 m depth in
the OGCM is well reproduced by the one-dimensional quasi-geostrophic (QG) vorticity equation with a windstress forcing. In
our analysis of the OGCM and QG results, we found that peaks and troughs of the time series of the Kuroshio volume transport
with 2–3 yr time-scale were induced by windstress curl, both local and immediately eastward, whereas longer time-scale variability
was also induced by windstress curl near the dateline. 相似文献
68.
69.
The circulation in the southern Huanghai Sea and northern East China Sea in June 1999 总被引:1,自引:0,他引:1
Yaochu Yuan Yonggang Liu Mingyu Zhou Arata Kaneko Zhou Yuan Noriaki Gohda 《海洋学报(英文版)》2003,22(3):321-332
On the basis of hydrographic data and current measurement (the mooring system, vessel-mounted ADCP and toward ADCP) data obtained in June 1999, the circulations in the southern Huang-hai Sea (HS) and northern East China Sea (ECS) are computed by using the modified inverse method. The Kuroshio flows northeastward through eastern part of the investigated region and has the main core at Section PN, a northward flow at the easternmost part of Section PN, a weaker anti-cyclonic eddy between these two northward flows, and a weak cyclonic eddy at the western part of Section PN. The above current structure is one type of the current structures at Section PN in ECS. The net northward volume transport (VT) of the Kuroshio and the offshore branch of Taiwan Warm Current (TWCOB) through Section PN is about 26.2×106m3/s in June 1999. The VT of the inshore branch of Taiwan Warm Current (TWCIB) through the investigated region is about 0.4×106m3/s. The Taiwan Warm Current (TWC) has much effect on the currents over the 相似文献
70.