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61.
Projected 21st century climate change on snow conditions over Shasta Dam watershed by means of dynamical downscaling 下载免费PDF全文
Snow is an important component of the Earth's climate system and is particularly vulnerable to global warming. It has been suggested that warmer temperatures may cause significant declines in snow water content and snow cover duration. In this study, snowfall and snowmelt were projected by means of a regional climate model that was coupled to a physically based snow model over Shasta Dam watershed to assess changes in snow water content and snow cover duration during the 21st century. This physically based snow model requires both physical data and future climate projections. These physical data include topography, soils, vegetation, and land use/land cover, which were collected from associated organizations. The future climate projections were dynamically downscaled by means of the regional climate model under 4 emission scenarios simulated by 2 general circulation models (fifth‐generation of the ECHAM general circulation model and the third‐generation atmospheric general circulation model). The downscaled future projections were bias corrected before projecting snowfall and snowmelt processes over Shasta Dam watershed during 2010–2099. This study's results agree with those of previous studies that projected snow water equivalent is decreasing by 50–80% whereas the fraction of precipitation falling as snowfall is decreasing by 15% to 20%. The obtained projection results show that future snow water content will change in both time and space. Furthermore, the results confirm that physical data such as topography, land cover, and atmospheric–hydrologic data are instrumental in the studies on the impact of climate change on the water resources of a region. 相似文献
62.
63.
The 1963 great Kurile earthquake was an underthrust earthquake occurred in the Kurile?CKamchatka subduction zone. The slip distribution of the 1963 earthquake was estimated using 21 tsunami waveforms recorded at tide gauges along the Pacific and Okhotsk Sea coasts. The extended rupture area was divided into 24 subfaults, and the slip on each subfault was determined by the tsunami waveform inversion. The result shows that the largest slip amount of 2.8?m was found at the shallow part and intermediate depth of the rupture area. Large slip amounts were found at the shallow part of the rupture area. The total seismic moment was estimated to be 3.9?×?1021?Nm (Mw 8.3). The 2006 Kurile earthquake occurred right next to the location of the 1963 earthquake, and no seismic gap exists between the source areas of the 1963 and 2006 earthquakes. 相似文献
64.
Stabilities of hexagonal new aluminous (NAL) phase and Ca-ferrite-type (CF) phase were investigated on the join NaAlSiO4-MgAl2O4 in a pressure range from 23 to 58 GPa at approximately constant temperature of 1,850 K, on the basis of in situ synchrotron
X-ray diffraction measurements in a laser-heated diamond-anvil cell. The results show that NAL is formed as a single phase
up to 34 GPa, NAL + CF between 34 and 43 GPa, and only CF at higher pressures in 40%NaAlSiO4-60%MgAl2O4 bulk composition. On the other hand, both NAL and CF coexist below 38 and 36 GPa, and only CF was obtained at higher pressures
in 60%NaAlSiO4-40%MgAl2O4 and 20%NaAlSiO4-80%MgAl2O4 composition, respectively. These results indicate that NAL appears only up to 46 GPa at 1,850 K, and CF forms continuous
solid solution at higher pressures on the join NaAlSiO4-MgAl2O4. NAL has limited stability in subducted mid-oceanic ridge basalt crust in the Earth’s lower mantle and undergoes a phase
transition to CF in deeper levels. 相似文献
65.
Keisuke Ishida Shigeyuki Suzuki Graciano P. Yumul Carla B. Dimalanta 《Gondwana Research》2011,19(1):61-70
The Cabog Formation, newly established herein and exposed in central East Luzon, Philippine Mobile Belt, is defined in age by the occurrence of radiolarians. The radiolarian assemblage is correlative with the middle Eocene and suggests a low paleolatitude affinity. The correlation, sedimentary environment, and the tectonic significance are discussed. The Cabog Formation is correlative with the distal part of the middle–late Eocene Caraballo Formation, which is exposed in the northeastern side of the Philippine Fault Zone. The sandstone composition and radiolarian age suggest that the Cabog Formation represents the first depositional stage in the early arc setting. The northward migration of the formation is also estimated in relation with the Philippine Sea Plate motion along the Older Philippine Fault from the equatorial area. 相似文献
66.
Toru YADA Akio FUJIMURA Masanao ABE Tomoki NAKAMURA Takaaki NOGUCHI Ryuji OKAZAKI Keisuke NAGAO Yukihiro ISHIBASHI Kei SHIRAI Michael E. ZOLENSKY Scott SANDFORD Tatsuaki OKADA Masayuki UESUGI Yuzuru KAROUJI Maho OGAWA Shogo YAKAME Munetaka UENO Toshifumi MUKAI Makoto YOSHIKAWA Junichiro KAWAGUCHI 《Meteoritics & planetary science》2014,49(2):135-153
Abstract– The Planetary Material Sample Curation Facility of JAXA (PMSCF/JAXA) was established in Sagamihara, Kanagawa, Japan, to curate planetary material samples returned from space in conditions of minimum terrestrial contaminants. The performances for the curation of Hayabusa‐returned samples had been checked with a series of comprehensive tests and rehearsals. After the Hayabusa spacecraft had accomplished a round‐trip flight to asteroid 25143 Itokawa and returned its reentry capsule to the Earth in June 2010, the reentry capsule was brought back to the PMSCF/JAXA and was put to a series of processes to extract recovered samples from Itokawa. The particles recovered from the sample catcher were analyzed by electron microscope, given their ID, grouped into four categories, and preserved in dimples on quartz slide glasses. Some fraction of them has been distributed for initial analyses at NASA, and will be distributed for international announcement of opportunity (AO), but a certain fraction of them will be preserved in vacuum for future analyses. 相似文献
67.
Masahiko Tanaka Tomoki Nakamura Takaaki Noguchi Aiko Nakato Hatsumi Ishida Toru Yada Kei Shirai Akio Fujimura Yukihiro Ishibashi Masanao Abe Tatsuaki Okada Munetaka Ueno Toshifumi Mukai 《Meteoritics & planetary science》2014,49(2):237-244
The crystallization temperatures of Itokawa surface particles recovered by the space probe Hayabusa were estimated by a plagioclase geothermometer using sodic plagioclase triclinicity. The Δ131‐index required for the thermometer, which is the difference in X‐ray diffraction peak positions between the 131 and 11 reflections of plagioclase, was obtained by a high‐resolution synchrotron Gandolfi camera developed for the third generation synchrotron radiation beamline, BL15XU at SPring‐8. Crystallization temperatures were successfully determined from the Δ131‐indices for four particles. The observed plagioclase crystallization temperatures were in a range from 655 to 660 °C. The temperatures indicate crystallization temperatures of plagioclases in the process of prograde metamorphism before the peak metamorphic stage. 相似文献
68.
We simulated two models of classical Cepheids with the same effective temperature and luminosity but different masses. Neither model has significant resonance among linear nonadiabatic periods of the fundamental, the first overtone, and the second overtone radial modes. The higher mass model found to approach to the second overtone-only state. The lower mass model shows a complicated three-mode interaction and none of the amplitudes of three modes is negligible. The relation of the higher mass model to the shortest period Cepheid HR 7308, and that of the lower mass model to the double-mode Cepheids are discussed. It appears that three-mode nonresonant coupling should be considered to explain the behaviours of both models. 相似文献
69.
T. Ishida 《Astrophysics and Space Science》1990,168(2):243-252
Amplitude equations, that are used in the investigation of stellar pulsations, for the three-mode nonresonant coupling case are inferred from that of the two-mode nonresonant coupling case. Characteristics of the fixed points of the amplitude equations are studied. Chaotic behaviour is expected when the amplitude equations consist of more than two modes. 相似文献
70.
T. Ishida 《Astrophysics and Space Science》1990,167(1):173-176
A criterion for the occurrence of double-mode pulsations is derived from linear adiabatic coupling coefficients The criterion indicates that double-mode pulsations of classical Cepheids occur at a shorter period range than the observed one, and that the evolutionary mass models are preferable for the double-mode pulsations. 相似文献