全文获取类型
收费全文 | 134篇 |
免费 | 2篇 |
国内免费 | 3篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 3篇 |
地球物理 | 34篇 |
地质学 | 41篇 |
海洋学 | 32篇 |
天文学 | 25篇 |
自然地理 | 3篇 |
出版年
2022年 | 1篇 |
2021年 | 4篇 |
2020年 | 6篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 3篇 |
2015年 | 1篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 2篇 |
2011年 | 6篇 |
2010年 | 3篇 |
2009年 | 4篇 |
2008年 | 7篇 |
2007年 | 6篇 |
2006年 | 4篇 |
2005年 | 1篇 |
2004年 | 5篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 3篇 |
2000年 | 4篇 |
1999年 | 1篇 |
1998年 | 2篇 |
1997年 | 3篇 |
1996年 | 5篇 |
1993年 | 1篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1989年 | 1篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 4篇 |
1981年 | 1篇 |
1980年 | 5篇 |
1979年 | 2篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1970年 | 2篇 |
1968年 | 1篇 |
1967年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有139条查询结果,搜索用时 156 毫秒
1.
Shinko Aoki 《Celestial Mechanics and Dynamical Astronomy》1987,42(1-4):309-354
A relation between the Celestial Reference System (CRS) and the Terrestrial Reference System is established theoretically by solving the equations of motion of a rigid Earth under the influence of the Sun and the Moon up to the second order perturbation. The solutions include not only nutation including Oppolzer terms but also the right ascension of the dynamical departure point (DP), as well as the wobble matrix.We have found that the kinematical definition of the Non-Rotating Origin NRO (for which our term is DP) given by Capitaine, Guinot and Souchay (1987) is not entirely equivalent to that included in the solutions of the equations of motion but shows perturbation, in particular when this is taken on the instantaneous equator. Besides this serious fault, we feel little merit in taking the DP as reference: (1) Unnecessary spurious mixed secular terms appear which come from the geometrical configuration that the DP leaves far and far from the ecliptic. (2) the DP moves secularly as well as oscillating with respect to space; this literally contradicts the term NRO, or is at least misleading. (3) It does not free us from the precession uncertainty to adopt DP as reference, since we cannot avoid virtual proper motions in terms of the current CRS. (4) No terms ignored hitherto are introduced, even if we take the DP properly chosen, i.e., on the equator of the celestial ephemeris pole. The transformation is only mathematical. There is no sufficient reason to take it instead of the equinox, which is observable in principle, as reference at the cost of the labor of changing all the textbooks, ephemerides, data and computer software now existing. 相似文献
2.
Seasonal and Spatial Variations of Iceberg Drift off Dronning Maud Land, Antarctica, Detected by Satellite Scatterometers 总被引:1,自引:0,他引:1
Shigeru Aoki 《Journal of Oceanography》2003,59(5):629-635
Seasonal and spatial variations of iceberg drift were studied using continuous satellite scatterometer images off Dronning
Maud Land, East Antarctica. Generally, iceberg drift speed showed a westward increase to the Greenwich Meridian. Seasonal
variations of the drift speed were high in autumn—early winter and low in spring, and their magnitudes also increased westward.
Seasonal variations of the drift speed were significantly correlated with variations of sea levels at Syowa and Mawson Stations,
and hence qualitatively consistent with geostrophic current variations. Thus, the scatterometer data are demonstrated to be
useful in monitoring iceberg trajectory and oceanic current variations.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
3.
Ichiro Ishikawa Shigeaki Aoki Ryo Furue Nobuo Suginohara 《Journal of Oceanography》1996,52(5):617-632
In recognition that similarity in the density balance leads to resemblance in circulation between the two-dimensional non-rotating and three-dimensional rotating systems which have similar density stratification, we investigate convection induced by cooling at one side wall and heating at the sea surface by using a two-dimensional non-rotating model as idealized representation for the deep Pacific circulation. In the model, various vertical profiles are taken for the side wall cooling, which are assumed to correspond to the density structure of the Anatarctic Circumpolar Current. In a small diffusivity range, two important features are found to be robust against change in the vertical profile of the side wall cooling. One is that the density stratification is horizontally almost uniform. The other is that the balance in the density equation between the vertical advection and the vertical diffusion holds in the interior. Consequently, the vertical density balance, together with the equation of continuity, determines the circulation pattern for the prescribed vertical profile of the side wall cooling. The multi-layered meridional flow, which is expected to exist in the deep Pacific, is shown to form for certain vertical profiles of the side wall cooling. 相似文献
4.
5.
The Princeton Ocean Model with realistic bottom topography has been used to investigate the summer temperature decrease in
the past 25 years in Fukuoka Bay. The vertical mixing of the model is expressed by a scheme that effectively includes the
influences of interannual variations of tidal currents and wind. The results show that the historical temperature decrease
in summer has been caused by tidal currents and wind weakening in the past 25 years in Fukuoka Bay. The weakening of tidal
currents and wind gives rise to weakening of the vertical mixing, and to enhancement of the estuarine circulation in the bay.
The enhancement of the estuarine circulation activates the inflow of open-ocean water toward Fukuoka Bay. Coastal water in
summer has therefore tended to be colder and more saline in the past 25 years. This interannual variation in coastal waters
is called “open-oceanization” in this study. On the basis of the numerical model, it is anticipated that the temperature will
decrease by 0.2°C in the next 25 years in Fukuoka Bay if the tide and wind weaken persistently as in the present bay. 相似文献
6.
7.
Naoki Shirai Yuzuru Karouji Kazuya Kumagai Masayuki Uesugi Kaori Hirahara Motoo Ito Naotaka Tomioka Kentaro Uesugi Akira Yamaguchi Naoya Imae Takuji Ohigashi Toru Yada Masanao Abe 《Meteoritics & planetary science》2020,55(7):1665-1680
Chemical compositions of materials used for new sample holders (vertically aligned carbon nanotubes [VACNTs] and polyimide film), which were developed for the analysis of Hayabusa2‐return samples, were determined by instrumental neutron activation analysis and/or instrumental photon activation analysis, to estimate contamination effects from the sample holders. The synthetic quartz plate used for the sample holders was also analyzed. Ten elements (Na, Al, Cr, Mn, Fe, Ni, Eu, W, Au, and Th) and 14 elements (Na, Al, K, Sc, Ti, Cr, Zn, Ga, Br, Sb, La, Eu, Ir, and Au) could be detected in the VACNTs and polyimide film, respectively. The VACNT data show that contamination by this material with respect to the Murchison meteorite is negligible in terms of the elemental ratios (e.g., Fe/Mn, Na/Al, and Mn/Cr) used for the classification of meteorites due to the extremely low density of VACNTs. However, for the Au/Cr ratio, even small degrees (1.7 wt%) of contamination by VACNTs will change the Au/Cr ratio. Elemental ratios used for the classification of meteorites are only influenced by large amounts of contamination (>60 wt%) of polyimide film, which is unlikely to occur. In contrast, detectable effects on Ti isotopic compositions are caused by >0.1 and >0.3 wt% contamination by VACNTs and polyimide film, respectively, and Hf isotopic changes are caused by >0.1 wt% contamination by VACNTs. The new sample holders (VACNTs and polyimide film) are suitable for chemical classification of Hayabusa2‐return samples, because of their ease of use, applicability to multiple analytical instruments, and low contamination levels for most elements. 相似文献
8.
Composite analysis was conducted using high-frequency radar data obtained during 2006–2015 in order to gain a better understanding of the current field in the Ariake Sea. The seasonally averaged surface current in the Ariake Sea was directed southward in all seasons, except around river mouths during summer. Heavy rainfall enhanced the outflow along the eastern coast of the Shimabara Peninsula from Isahaya Bay to the southern area 2–5 days after heavy rainfall. Spring–neap differences were clearly seen in the southward current along the Shimabara Peninsula. Interannual variation in the M2 tidal current amplitude was synchronized with the lunar nodal cycle. 相似文献
9.
Ken-ichiro Aoki 《Contributions to Mineralogy and Petrology》1970,25(4):284-288
Andesine megacrysts up to 3 cm in size occur sporadically in certain alkali basalts and allied mafic rocks in southwestern Japan. They are sometimes accompanied by megacrysts of mafic minerals and ultramafic and mafic inclusions. Nine andesines have been chemically analysed.From the petrography and chemistry and the results of high pressure experimental work, it is suggested that andesine megacrysts crystallized from alkali basalt magma under dry conditions at a depth of about 30 to 60 km. 相似文献
10.
E. E. Larson R. L. Reynolds R. Merrill S. Levi M. Ozima Y. Aoki H. Kinoshita S. Zasshu N. Kawai T. Nakajima K. Hirooka 《Bulletin of Volcanology》1974,38(1):361-377
Volcanic rocks from six of the currently or recently active volcances of the Mariana Island are show little variation in major element abundances. SiO2 content averages 51.5 wt.%. The flows are high in Al2O (mean 17.7 wt.%) and Fe oxides (mean 10.1 wt.% calculated as FeO only), and moderate in MgO content (mean 4.7 wt.%), Na2O (mean 2.7 wt.%), and K2O (mean 0.7 wt.%). Only the rocks from Farallon de Pajaros, the northernmost of the Mariana Islands, deviate slightly from the average of the analyses. Three analyses from this island are slightly higher in SiO2 (about 54 wt.%) and Al2O3, and are lower in total Fe oxides and MgO. According to preferred classification, the lavas of the Mariana Islands can be termed mela-andesites, high-alumina basalts, or calc-alkaline (orogenic) basalts. The K2O values (mean 0.7 wt.%) obtained from lavas of the Mariana Islands are significantly higher than the K2O values (about 0.33 wt.%) from volcanics of the Izu chain to the north. Inasmuch as the substantial scatter in location of earthquake foci beneath both arcs prevents accurate delineation of the upper boundary of the Benioff zone, it presently cannot be determined whether this discrepancy in K2O values reflects a difference in depth from the volcanic are to the dipping seismic zone or relates to other phenomena. The older volcanic islands within the Mariana-Bonin island chain apparently defined an island arc system during Eocene to Miocene time. This indicates that the present plane of convergence between the Pacific plate and the Philippine Sea plate has defined the convergence between these plates since Eocene time. 相似文献