全文获取类型
收费全文 | 173篇 |
免费 | 2篇 |
国内免费 | 1篇 |
学科分类
地球科学 | 176篇 |
出版年
2024年 | 1篇 |
2022年 | 2篇 |
2018年 | 6篇 |
2017年 | 5篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 4篇 |
2013年 | 4篇 |
2012年 | 1篇 |
2011年 | 5篇 |
2010年 | 2篇 |
2009年 | 6篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 4篇 |
2005年 | 5篇 |
2004年 | 9篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 3篇 |
1998年 | 4篇 |
1997年 | 7篇 |
1996年 | 3篇 |
1995年 | 5篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 6篇 |
1991年 | 1篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1988年 | 3篇 |
1987年 | 5篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 7篇 |
1980年 | 4篇 |
1979年 | 2篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1967年 | 1篇 |
排序方式: 共有176条查询结果,搜索用时 15 毫秒
1.
Takashi T. Sakamoto L. Shogo Urakawa Hiroyasu Hasumi Miho Ishizu Sachihiko Itoh Teruhisa Komatsu Kiyoshi Tanaka 《Journal of Oceanography》2017,73(1):39-54
A numerical simulation of Otsuchi Bay located on the northeast coast of the Honshu, the largest island of Japan, is conducted, using an ocean general circulation model (OGCM) with a nested-grid system in order to illustrate seasonal variability of the circulation in the bay. Through a year, an anticlockwise circulation is dominant in the bay, as observational studies have implied, although it is modified in the bay-mouth-half of the bay in winter. In addition, there is an intense outflow at the surface layer during spring to autumn, influenced by river water discharge. Intrusion of the Pacific water into the bay is influened by mean circulations, but it is also influenced by baroclinic tides from spring to autumn. Pacific water intrusions affected by baroclinic tides may have an impact on the environment in Otsuchi Bay. 相似文献
2.
We present a theoretical investigation of non-equilibrium condensation of refractory metalsinthe primordial solar nebula, in relation to the origin of “Fremdlinges” included inCAIs. Todescribe the nucleation process of grains from vapor, weadopted asemi-phenomenological modelmodified fromthe classical nucleation theoryby the introductionof the second virial coefficient of vapor. This modelachieves excellent agreement with nucleation rate experiment. However,the second virial coefficients are unknown for a vapor of refractory metals. To overcome this, weexpress the nucleation rate by theuse of the chemical potential of dimersinsteadof the second virial coefficient.On the basis of this new nucleation theory,we have performed numerical simulations ofnon-equilibrium condensation of refractory metals andfind thattheircondensation temperatures, Tc, decrease considerably in comparison withequilibrium condensation. Even if the characteristiccooling time scale is aslarge as 1×105 years, the decrease in Tc isfrom 200 to 400 Kfor rare elements such as W, Re,and Os. This remarkablenon-equilibrium behaviormainly stemsfromthelow totalpressure in the primordial solar nebula. From our new modelwealso obtainthe typical size ofgrainsformed in condensation. We findthatthe cooling time should be ?1×105 years for sub-micron-sized or largerrefractory metal nuggetsto form. 相似文献
3.
The physico-chemical states of artificial radionuclides,90Sr,137Cs and144Ce in seawater were investigated by radiochemical analysis of filtered and unfiltered seawater. The difference of radionuclide concentrations between unfiltered and filtered seawaters was defined as the particulate form radioisotope and its particle ratio was discussed.Practically no particulate90Sr, greater than 0.22 in size, was observed in both coastal and open seawaters, but some of137Cs seemed to be insoluble in some circumstances, especially in coastal waters. A considerable amount of144Ce was found to be particulate.An estimation of the radionuclides in particulate form was made for Kashima-nada seawaters collected in 1970 to 1972, and it was shown that the possible occurrence of particulate radionuclides, greater than 0.22 in size, were 1% or less for90Sr and 6% for137Cs. In the coastal water, 80 % of144Ce were seemed to be in particulate form, but in the open seawater only a few%. The influences of suspended materials to137Cs and144Ce concentration levels in seawater were not negligible and further investigations are desirable. 相似文献
4.
Jean-Marie Auzende Eiichi Honza Xavier Boespflug Satendra Deo Jean-Philippe Eissen Jun Hashimoto Philippe Huchon Junichiro Ishibashi Yo Iwabuchi Philip Jarvis Masato Joshima Kiyoyuki Kisimoto Yasuto Kuwahara Yves Lafoy Tsuyoshi Matsumoto Jean-Pierre Maze Kiyohiko Mitsuzawa Hiroyasu Monma Takeshi Naganuma Yukihiro Nojiri Suguru Ohta Kiyoshi Otsuka Yoshihisa Okuda Hélène Ondreas Akira Otsuki Etienne Ruellan Myriam Sibuet Manabu Tanahashi Takeo Tanaka Tetsuro Urabe 《Marine Geophysical Researches》1990,12(4):269-283
The aim of the Japanese-French Kaiyo 87 cruise was the study of the spreading axis in the North Fiji Basin (SW Pacific). A
Seabeam and geophysical survey allowed us to define the detailed structure of the active NS spreading axis between 16° and
22° S and its relationships with the left lateral motion of the North Fiji Fracture Zone. Between 21° S and 18°10′ S, the
spreading axis trends NS. From 18°10 S to 16°40 S the orientation of the spreading axis changes from NS to 015°. North of
16°40′ S the spreading axis trends 160°. These two 015° and 160° branches converge with the left lateral North Fiji fracture
zone around 16°40′ S to define an RRFZ triple junction. Water sampling, dredging and photo TV deep towing give new information
concerning the hydrothermal activity along the spreading axis. The discovery of hydrothermal deposits associated with living
communities confirms this activity. 相似文献
5.
Spectro-polarimetric observations of active regions were carried out in the spectral lines of Sii 10827.1 Å and Hei 10830 Å to study the three-dimensional magnetic field structure and associated plasma flow properties. Comparison of Sii and Hei magnetograms with the potential field model shows that a large fraction of the magnetic field is consistent with the potential field structure, by assuming that the height difference between the origin of the two lines is about 1200 km. The slope of the scatter plot between Sii and Hei magnetograms is 0.5, 0.76 in an emerging flux and a larger active region, respectively. These values are lower than the scatter plot slopes obtained from Kitt Peak photospheric and chromospheric magnetograms, in which case the corresponding values are 0.83 and 0.9, respectively. Considering the height difference between these two sets of chromospheric magnetograms, this implies that the magnetic field spreads out faster near the transition region heights. Dopplergrams obtained by determining the centroid of the asymmetric line profiles show that, in case of emerging flux region, the chromospheric upflow regions are located in the magnetic neutral line areas. 相似文献
6.
Hiroko Watanabe Alexandra Tritschler Reizaburo Kitai Kiyoshi Ichimoto 《Solar physics》2010,266(1):5-16
We performed two-dimensional spectroscopic observations of the preceding sunspot of NOAA 10905 located off disk center (S8
E36, μ≈0.81) by using the Interferometric BI-dimensional Spectrometer (IBIS) operated at the Dunn Solar Telescope (DST) of the National
Solar Observatory, New Mexico. The magnetically insensitive Fe I line at 709.04 nm was scanned in wavelength repetitively
at an interval of 37 s to calculate sequences of maps of the line-wing and line-core intensity, and the line-of-sight Doppler
velocity at different line depths (3% to 80%). Visual inspection of movies based on speckle reconstructions computed from
simultaneous broadband data and the local continuum intensity at 709.04 nm revealed an umbral dot (UD) intruding rapidly from
the umbral boundary to the center of the umbra. The apparent motion of this object was particularly fast (1.3 km s−1) when compared to typical UDs. The lifetime and size of the UD was 8.7 min and 240 km, respectively. The rapid UD was visible
even in the line-core intensity map of Fe I 709.04 nm and was accompanied by a persistent blueshift of about 0.06 km s−1. 相似文献
7.
Jun-ichi Ando Kiyoshi Fujino Toru Takeshita 《Physics of the Earth and Planetary Interiors》1993,80(3-4):105-116
Dislocation microstructures of naturally deformed silicate garnets and olivines in garnet-peridotites and silicate garnets in eclogites from four localities have been observed with a transmission electron microscope (TEM) to clarify the dislocation characteristics of silicate garnets. We have obtained the following results: (1) dislocation densities of garnets in all the garnet-peridotites (ρ = 105−107 cm−2) are always nearly an order of magnitude lower than those of co-existing olivines; (2) dislocation densities of garnets in eclogites (ρ = 105−108 cm−2) which are embedded in garnet-peridotites are almost an order of magnitude higher than those of garnets in the surrounding garnet-peridotites; (3) the dominant Burgers vector, b, of mainly edge dislocations in garnet is 100 for specimens with dislocation density ρ = 105−106 cm−2, while b=1/2111 for specimens with ρ = 107−108 cm−2. Result (1) indicates that the observed dislocations in garnets were formed by plastic deformation under the same stresses as for co-existing olivines, and that there is a similar relationship between applied stress and dislocation density for garnets as for olivines. Result (2) suggests that the stress concentration occurred around eclogites embedded in garnet-peridotites, and the resulting differential stress in garnets in eclogites was further elevated by the interlocking of neighboring hard garnet grains. Finally, result (3) indicates that the dominant Burgers vector of mainly edge dislocations in garnet changes from 100 to 1/2111 with increasing applied differential stress. 相似文献
8.
9.
The full waveform synthetic seismogram of multiple scatteredSH waves by many cylindrical cavities in two-dimensional homogeneous elastic media is computed. We used the so-called single-layer potential integral representation of the scattered field and a discretization scheme with line source distribution for each cavity. The total field is the sum of the incident wave plus the field radiated from all sources, each multiplied by an unknown complex constant representing its strength. These constants are determined by imposing the appropriate boundary conditions in the least-squares sense. Here we solve scattering problems involving one, two, four, twelve and fifty cavities regularly distributed in a half-space. The seismograms computed along the free-surface show regions where the incident wave is strongly attenuated, as well as the arrivals of all multiple scattered phases. The accuray of the method is estimated from the degree of agreement of our solution for one cavity with the corresponding analytical solution, and also from the magnitude of the residual tractions along the boundaries of two cavities separated at various distances. Finally we apply the method to compute the case of fifty cylindrical cavities, each of radiusa, randomly distributed in a region 80a wide by 30a deep in a half-space. The value of scattering loss is obtained from the amplitude decay of the primary wave with distance for wavelengths in the range from 1.7a to 13.3a, using the synthetic seismogram calculated for the same distribution of 50 cavities as above, but in full-space. 相似文献
10.
Takeshi Ohmura Takeo Moriya Chengshi Piao Takaya Iwasaki Toshikastu Yoshi Shin'ichi Sakai Tetsuya Takeda Kaoru Miyashita Humihito Yamazaki Kiyoshi Ito Akira Yamazaki Yoji Shimada Katsuya Tashiro Hiroki Miyamachi 《Island Arc》2001,10(3-4):215-227
Abstract The 1995 Kobe (Hyogo-ken Nanbu) earthquake (MJMA 7.2, Mw 6.9) occurred on Jan. 17, 1995, at a depth of 17 km, beneath the areas of southern part of Hyogo prefecture and Awaji Island. To investigate P-wave velocity distribution and seismological characteristics in the aftershock area of this great earthquake, a wide-angle and refraction seismic exploration was carried out by the Research Group for Explosion Seismology (RGES) . The profile including 6 shot points and 205 observations was 135 km in length, extending from Keihoku, Northern Kyoto prefecture, through Kobe, to Seidan on Awaji Island. The charge of each shot was 350–700 kg. The P-wave velocity structure model showed a complicated sedimentary layer which is shallower than 2.5 km, a 2.5 km-thick basement layer whose velocity is 5.5 km/s, overlying the crystalline upper crust, and the boundary between the upper and lower crust.
Almost all aftershock hypocenters were located in the upper crust. However, the structure model suggests that the hypocenters of the main shock and some aftershock clusters were situated deeper than the boundary between the upper and lower crust. We found that the P-velocity in the upper crust beneath the northern part of Awaji Island is 5.64 km/s which is 3% lower than that of the surrounding area. The low-velocity zone coincides with the region where the high stress moment release was observed. 相似文献
Almost all aftershock hypocenters were located in the upper crust. However, the structure model suggests that the hypocenters of the main shock and some aftershock clusters were situated deeper than the boundary between the upper and lower crust. We found that the P-velocity in the upper crust beneath the northern part of Awaji Island is 5.64 km/s which is 3% lower than that of the surrounding area. The low-velocity zone coincides with the region where the high stress moment release was observed. 相似文献