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123.
The objective of this paper is to provide an analytical basis for the quantitative evaluation of damage to a reinforced concrete
structure based on the vibration data obtained by using the damage detection technique. A partial reinforced concrete system
of a weak beam/strong column moment frame is chosen as an example. A pushover analysis is carried out in order to numerically
examine both the story shear-relative displacement characteristics and the associated damage level. In the analysis, a two
dimensional nonlinear finite element analysis is employed considering several constitutive models. As a result, the degradation
of the stiffness at the damaged story is characterized in association with the story relative displacement. It is also pointed
out that the rotation angle of the column-base is highly correlated with the story relative displacement. Based on the analytical
findings, quantitative approaches for a structural health monitoring system are suggested considering both the current sensor
technologies and those available in the future.
Supported by: Ministry of Education, Science, Sports and Culture, Grant-in-Aid for Scientific Research (Base Research (c)
(1), Research No. 14550555) 相似文献
124.
Yoshio Inoue Yoshiyuki Kiyono Hidetoshi Asai Yukihito Ochiai Jiaguo Qi Albert Olioso Tatsuhiko Shiraiwa Takeshi Horie Kazuki Saito Linkham Dounagsavanh 《International Journal of Applied Earth Observation and Geoinformation》2010
In the tropical mountains of Southeast Asia, slash-and-burn (S/B) agriculture is a widely practiced and important food production system. The ecosystem carbon stock in this land-use is linked not only to the carbon exchange with the atmosphere but also with food and resource security. The objective of this study was to provide quantitative information on the land-use and ecosystem carbon stock in the region as well as to infer the impacts of alternative land-use and ecosystem management scenarios on the carbon sequestration potential at a regional scale. The study area was selected in a typical slash-and-burn region in the northern part of Laos. The chrono-sequential changes of land-use such as the relative areas of community age and cropping (C) + fallow (F) patterns were derived from the analysis of time-series satellite images. The chrono-sequential analysis showed that a consistent increase of S/B area during the past three decades and a rapid increase after 1990. Approximately 37% of the whole area was with the community age of 1–5 years, whereas 10% for 6–10 years in 2004. The ecosystem carbon stock at a regional scale was estimated by synthesizing the land-use patterns and semi-empirical carbon stock model derived from in situ measurements where the community age was used as a clue to the linkage. The ecosystem carbon stock in the region was strongly affected by the land-use patterns; the temporal average of carbon stock in 1C + 10F cycles, for example, was greater by 33 MgC ha−1 compared to that in 1C + 2F land-use pattern. The amount of carbon lost from the regional ecosystems during 1990–2004 periods was estimated to be 42 MgC ha−1. The study approach proved to be useful especially in such regions with low data-availability and accessibility. This study revealed the dynamic change of land-use and ecosystem carbon stock in the tropical mountain of Laos as affected by land-use. Results suggest the significant potential of carbon sequestration through changing land-use and ecosystem management scenarios. These quantitative estimates would be useful to better understand and manage the land-use and ecosystem carbon stock towards higher sustainability and food security in similar ecosystems. 相似文献
125.
Akihiko Ito Koki Ouchi Isamu Hisa Susumu Seki Yoshio Seto Shoji Kurashina 《Journal of Oceanography》1984,40(2):98-104
In the consideration of safety it is required that packages containing radioactive wastes when dumped at sea should keep their
integrity and retain their contents until they reach the seabed. Packages containing simulated radioactive wastes (non-radioactive)
were tested by a free-fall method at depthsca. 4,300 m in an area for dumping industrial waste off Shikoku Island. Since the weight of the largest package was 4,300 kg,
special attention was paid to the connection of a buoyancy system with mooring rope. Descent and ascent velocities of the
free-fall system were calculated prior to the experiment. A free-fall experiment with an extremely heavy object, heavier than
ever previously reported, was accomplished without trouble by using the free-fall system. Recovery of a camera, flash-light,
and other components was successful in each of the three experiments. Successive photographing of the package during descent
was made and its integrity was observed using the photographs taken by the recovered camera. The packages remained intact
during descent and at least for a short time after arrival on the seabed. 相似文献
126.
Summary . The great Etorofu earthquake of 1958 November 6 is characterized by a relatively small aftershock area (70 × 150 km2 ) and an extremely large felt area. The felt area is more extensive than those of any other large earthquakes which have occurred in the southern Kurile to northern Japan arc since the beginning of this century. The mechanism is a pure thrust fault typical of most great earthquakes in island arcs. A body wave magnitude of m b = 8.2 is obtained at periods around 6 s using more than 40 observations, although an m b value of only 7.6–7.7 would be expected empirically from the observed surface wave magnitude of M s = 8.1–8.2. Both an unusually large felt area and a high m b indicate a dominance of high-frequency components in the seismic waves. A seismic moment of M o = 4.4 × 1028 dyne cm is determined from long-period surface waves from which a high stress drop of Δσ = 78 bar is obtained using a relatively small aftershock area. Historic data indicate an anomalously long time interval between the 1958 event and any earlier great earthquake from the same source region. The observed high stress drop can be interpreted as a consequence of this long intervening period through which strain built up. The dominance of the high-frequency seismic waves can then be interpreted as a result of this high stress drop. Stress drops, seismic wave spectra and recurrence intervals of great earthquakes are in this way closely related to each other. The 1958 event may represent a high strength extreme of stochastic fluctuation of fracture strength relevant to great earthquakes. 相似文献
127.
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