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71.
K. Iwasawa G. Matt A.C. Fabian S. Bianchi W.N. Brandt M. Guainazzi T. Murayama Y. Taniguchi 《Monthly notices of the Royal Astronomical Society》2001,326(1):119-125
We report on the BeppoSAX detection of a hard X-ray excess in the X-ray spectrum of the classical high-ionization Seyfert 2 galaxy Tol 0109–383. The X-ray emission of this source observed below 7 keV is dominated by reflection from both cold and ionized gas, as seen in the ASCA data. The excess hard X-ray emission is presumably caused by the central source absorbed by an optically thick obscuring torus with N H ∼2×1024 cm−2 . The strong cold X-ray reflection, if it is produced at the inner surface of the torus, is consistent with the picture where much of the inner nucleus of Tol 0109–383 is exposed to direct view, as indicated by optical and infrared properties. However, the X-ray absorption must occur at small radii in order to hide the central X-ray source but leave the optical high-ionization emission-line region unobscured. This may also be the case for objects such as the Seyfert 1 galaxy Mrk231. 相似文献
72.
Mónica Vásquez Uwe Altenberger Rolf L. Romer Masafumi Sudo Juan Manuel Moreno-Murillo 《Journal of South American Earth Sciences》2010,29(2):171-186
The Eastern Cordillera of the Colombian Andes represents an inverted Cretaceous basin where Cretaceous magmatism is characterized by rare mafic dykes and sills. We use 40Ar/39Ar, Sr–Nd–Pb isotopes, as well as major and trace elements analyses of Cretaceous intrusions from both flanks of the Eastern Cordillera in combination with structural data to document the complex evolution of the basin. Magmatism, which is diachronous and geochemically diverse, seems to be related to mantle melting beneath the most subsiding segments of each sub-basin during enhanced extensional tectonics. The mafic intrusions display two different compositional series: an alkaline one with OIB-like pattern and a tholeiitic one with MORB-like features. This indicates at least two diverse mantle sources. Trace-element patterns suggest that the intrusions were emplaced in an extensional setting. 40Ar/39Ar dating on primary plagioclase and hornblende provides plateau ages between ~136 and ~74 Ma.The geochemical and temporal diversities show that the emplacement of the magmas was tectonically controlled, each sub-basin reflecting an individual subsidence event. 相似文献
73.
Masafumi Kamachi Tsurane Kuragano Noriya Yoshiok Jiang Zhu Francesco Uboldi 《大气科学进展》2001,18(5):767-786
l. IntroductionLinear dynamics ls domlnant as a response to atmospheric forcing in the equatrialregion. In the mid-- to high--latitudes, ocean represents nonlinear phenomena such as strongcurrents and meso--scale eddies. Heat and water fluxes are also important. The resultantscales of the phenomena are rather small. We developed, for the mid-- to high--latitudes, anocean data assimilation system COMPASS--K: Comprehensive Ocean ModeIing, Prediction,Analysis and Synthesis System in the K… 相似文献
74.
Yoshimitsu Fukushima Masafumi Mori Shin'ichi Matsuzaki Shuji Kobayashi Yuki Ohno 《Journal of Seismology》2001,5(1):63-72
A semi-empirical approach using fore- or after-shockrecords as Green's functions is applicable to thesimulation of strong ground motion, however suchrecords are obviously not available for predictionpurposes. Thus we have predicted ground motion fora hypothetical large earthquake from other minorevents by adopting a distance correction based ongeometrical spreading. Another difficulty inprediction is fault modeling. Surface traces weresimplified as fault models 27, 46, 55, and 77 km inlength. Further, the actual fault rupture may beinhomogeneous, so an asperity distribution isassumed. This asperity model assumes thatdislocation and stress drop are double than theaverage values. Although, the near field term isneglected in our simulation, no significantdifference was seen in the motions estimated byindividual models for periods up to 2.0 seconds. This indicates that the dependence of source size issmall for strong motion, perhaps as a result of therandom summation of high-frequency phases. 相似文献
75.
Noriko Hasebe Ayako Fukutani Masafumi Sudo Takahiro Tagami 《Bulletin of Volcanology》2001,63(6):377-386
K-Ar ages were measured on Quaternary polygenetic and monogenetic volcanoes in the Higashi-Izu region, Izu peninsula, central Japan, using the unspiked sensitivity method with mass-fractionation correction procedure to investigate when eruptive style changed, whether a hiatus existed between the two types of eruptive activity, and the effect of tectonics on the change in eruptive style. The K-Ar ages range from 0.3-0.08 Ma for monogenetic volcanoes and from 1.8-0.2 Ma for polygenetic volcanoes; thus, no volcanic hiatus was found between the two types of eruptive styles. The transition from polygenetic to monogenetic volcanism occurred during a time of overlap between 0.3 and 0.2 Ma, after collision of the Izu block (the future Izu peninsula) with central Japan, estimated as 1.0-0.8 Ma by previous researchers. Based on the review of several tectonic models of the area, the measured age of transition in eruptive style is interpreted to correspond to the change in the stress field of the Higashi-Izu region. 相似文献
76.
Yoshinobu Tsuji Hideo Matsutomi Fumihiko Imamura Minoru Takeo Yoshiaki Kawata Masafumi Matsuyama Tomoyuki Takahashi Sunarjo Prih Harjadi 《Pure and Applied Geophysics》1995,144(3-4):481-524
A field survey of the 1992 Flores Island earthquake tsunami was conducted during December 29, 1992 to January 5, 1993 along the north coast of the eastern part of Flores Island. We visited over 40 villages, measured tsunami heights, and interviewed the inhabitants. It was clarified that the first wave attacked the coast within five minutes at most of the surveyed villages. The crust was uplifted west of the Cape of Batumanuk, and subsided east of it. In the residential area of Wuring, which is located on a sand spit with ground height of 2 meters, most wooden houses built on stilts collapsed and 87 people were killed even though the tsunami height reached only 3.2 meters. In the two villages on Babi Island, the tsunami swept away all wooden houses and killed 263 of 1,093 inhabitants. Tsunami height at Riang-Kroko village on the northeastern end of Flores Island reached 26.2 meters and 137 of the 406 inhabitants were killed by the tsumani. Evidence of landslides was detected at a few points on the coast of Hading Bay, and the huge tsunami was probably formed by earthquake-induced landslides. The relationship between tsunami height and mortality was checked for seven villages. The efficiencies of trees arranged in front of coastal villages, and coral reefs in dissipating the tsunami energy are discussed. 相似文献
77.
Tectono‐sedimentary evolution of the northern Iranian Plateau: insights from middle–late Miocene foreland‐basin deposits
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Paolo Ballato Francesca Cifelli Ghasem Heidarzadeh Mohammad R. Ghassemi Andrew D. Wickert Jamshid Hassanzadeh Guillaume Dupont‐Nivet Philipp Balling Masafumi Sudo Gerold Zeilinger Axel K. Schmitt Massimo Mattei Manfred R. Strecker 《Basin Research》2017,29(4):417-446
Sedimentary basins in the interior of orogenic plateaus can provide unique insights into the early history of plateau evolution and related geodynamic processes. The northern sectors of the Iranian Plateau of the Arabia–Eurasia collision zone offer the unique possibility to study middle–late Miocene terrestrial clastic and volcaniclastic sediments that allow assessing the nascent stages of collisional plateau formation. In particular, these sedimentary archives allow investigating several debated and poorly understood issues associated with the long‐term evolution of the Iranian Plateau, including the regional spatio‐temporal characteristics of sedimentation and deformation and the mechanisms of plateau growth. We document that middle–late Miocene crustal shortening and thickening processes led to the growth of a basement‐cored range (Takab Range Complex) in the interior of the plateau. This triggered the development of a foreland‐basin (Great Pari Basin) to the east between 16.5 and 10.7 Ma. By 10.7 Ma, a fast progradation of conglomerates over the foreland strata occurred, most likely during a decrease in flexural subsidence triggered by rock uplift along an intraforeland basement‐cored range (Mahneshan Range Complex). This was in turn followed by the final incorporation of the foreland deposits into the orogenic system and ensuing compartmentalization of the formerly contiguous foreland into several intermontane basins. Overall, our data suggest that shortening and thickening processes led to the outward and vertical growth of the northern sectors of the Iranian Plateau starting from the middle Miocene. This implies that mantle‐flow processes may have had a limited contribution toward building the Iranian Plateau in NW Iran. 相似文献
78.
Toyoda Takahiro Fujii Yosuke Kuragano Tsurane Kosugi Naohiro Sasano Daisuke Kamachi Masafumi Ishikawa Yoichi Masuda Shuhei Sato Kanako Awaji Toshiyuki Hernandez Fabrice Ferry Nicolas Guinehut Stéphanie Martin Matthew Andrew Peterson K. Good Simon A. Valdivieso Maria Haines Keith Storto Andrea Masina Simona Köhl Armin Yin Yonghong Shi Li Alves Oscar Smith Gregory Chang You-Soon Vernieres Guillaume Wang Xiaochun Forget Gael Heimbach Patrick Wang Ou Fukumori Ichiro Lee Tong Zuo Hao Balmaseda Magdalena 《Climate Dynamics》2017,49(3):891-907
Climate Dynamics - The interannual-decadal variability of the wintertime mixed layer depths (MLDs) over the North Pacific is investigated from an empirical orthogonal function (EOF) analysis of an... 相似文献
79.
K–Ar geochronology of a Quaternary monogenetic volcano group in Ojika Jima District, Southwest Japan
Masafumi Sudo Kozo Uto Yoshiyuki Tatsumi Kazunori Matsui 《Bulletin of Volcanology》1998,60(3):171-186
An unspiked K–Ar dating method using a mass-fractionation correction procedure was applied to a Quaternary independent group
of monogenetic volcanoes, Ojikajima Volcano Group, located in northwestern Kyushu in Southwest Japan, in order to clarify
in detail secular variations in eruptive volume, locations of eruptive vents, and magma compositions in a single monogenetic
volcano group. The major results were as follows: (a) K–Ar ages of monogenetic volcanoes distribute from 1.08 to 0.30 Ma,
with voluminous peaks at approximately 1.0 and 0.6 Ma. (b) The volcanic activity commenced in the central part of the field,
expanded to the whole field at approximately 0.6 Ma, and then shrank to the central area. (3) Concentrations of incompatible
elements, such as Ba, K, and Nb, increase with decreasing age, whereas P, Y, and Zr concentrations remain constant. These
concentrations suggest gradual decrease in the degree of partial melting from an identical mantle source with residual garnet.
Received: 15 December 1997 / Accepted: 23 May 1998 相似文献
80.
Sea surface height anomaly maps of realistic eddy activity were obtained by applying space-time optimum interpolation to altimeter
data. Analysis error and rate of reconstructing eddy signals were investigated by taking account of: 1) dependency on orbit
configurations of single and multiple altimeters; 2) dependency on space-time scales of realistic, dominant eddies; and 3)
effect of space-time scales of eddy propagation. Large-scale sea surface height anomalies are subtracted from altimeter data
by applying an along-track filter to allow easy handling of eddy signals. The space-time scales of the first-guess error in
the optimum interpolation are statistically evaluated by fitting a space-time anisotropic Gaussian function to space-time-distributed
correlation coefficients of sea surface height using the TOPEX data. The results of the optimum interpolation clarify the
followings: 1) ERS has a better capability of reconstructing eddy signals than TOPEX. Comparison of maps from multi-altimeter
data shows that TOPEX+ERS has a better capability than Jason−1+TOPEX in lower latitudes and vice versa in higher latitudes,
though the differences are small. 2) The small space-time scale yields a low reconstruction rate in marginal seas and alongside
the equator. The persistent timescale is large, and westward propagation is dominant in the subtropical and subarctic regions,
where the reconstruction rates are high. 3) The optimum interpolation, taking account of eddy propagation, provides higher
reconstruction rates than that taking no account of the propagation. The effect of propagation on the optimum interpolation
is greater when it is applied to single-altimeter data than to multi-altimeter data.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献