全文获取类型
收费全文 | 164篇 |
免费 | 5篇 |
国内免费 | 1篇 |
专业分类
测绘学 | 1篇 |
大气科学 | 4篇 |
地球物理 | 35篇 |
地质学 | 78篇 |
海洋学 | 32篇 |
天文学 | 11篇 |
综合类 | 1篇 |
自然地理 | 8篇 |
出版年
2021年 | 3篇 |
2020年 | 2篇 |
2018年 | 2篇 |
2017年 | 6篇 |
2016年 | 6篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 6篇 |
2012年 | 12篇 |
2011年 | 6篇 |
2010年 | 7篇 |
2009年 | 5篇 |
2008年 | 13篇 |
2007年 | 9篇 |
2006年 | 6篇 |
2005年 | 5篇 |
2004年 | 7篇 |
2003年 | 12篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 3篇 |
1999年 | 4篇 |
1998年 | 2篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1987年 | 2篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 3篇 |
1982年 | 1篇 |
1980年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1975年 | 1篇 |
1974年 | 2篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1969年 | 2篇 |
1968年 | 2篇 |
排序方式: 共有170条查询结果,搜索用时 203 毫秒
91.
Ishimaru Satoko; Arai Shoji; Ishida Yoshito; Shirasaka Miki; Okrugin Victor M. 《Journal of Petrology》2007,48(2):395-433
92.
Nagayoshi Katsuta Masao Takano Shin-ichi Kawakami Shoji Togami Hitoshi Fukusawa Mineo Kumazawa Yoshinori Yasuda 《Journal of Paleolimnology》2007,37(2):259-271
Event-related sedimentary layers, which are deposited occasionally due to volcanic eruptions, earthquakes or heavy rains,
are often contained in the rhythmical sequences of lacustrine and marine sediments. We have developed an analytical method
for separating the sedimentary rhythms and the event layers identified using the scanning X-ray analytical microscope (SXAM)
and obtained sequential profiles of seven elements Al, Si, K, Ca, Ti, Mn, and Fe in the lacustrine sediment from Lake Suigetsu,
Japan. Two types of event layers could be detected from the elemental composition of 33 layers of sediment: three known volcanic
ash layers and 30 clay layers containing 12 turbidites. The recurrence interval of the latter, which may potentially be initiated
and archived by locally important earthquakes, is estimated to be an average of 640 ± 160 years by using Sompi event analysis
(SEA) based on an autoregressive (AR) model. After removing those portions that represented event layers from the elemental
profiles, we obtained event-removed (ER) temporal profiles based on the tephrochronology of the three volcanic ash layers.
The ER temporal profiles of manganese and iron, probably representing the siderite content, showed a millennial-scale variation
in the Holocene that corresponded well with ice-rafting events in the North Atlantic. 相似文献
93.
Dania Tristá-Aguilera Fernando Barra Joaquin Ruiz Diego Morata Oscar Talavera-Mendoza Shoji Kojima Fernando Ferraris 《Mineralium Deposita》2006,41(1):99-105
The Lince–Estefanía stratabound copper deposit in the Michilla district is one of the most important deposits in the Coastal Cordillera of northern Chile and is one of the most representative of this type of deposit. Chalcocite and bornite characterize the main stage of hypogene copper sulfide mineralization. Rhenium and osmium isotopes are used here to constrain the age of hypogene mineralization and the source of osmium contained in these ore minerals. A Re–Os isochron yielded an age of 160±16 Ma (2σ), with an associated initial 187Os/188Os ratio of 1.06±0.09 (mean square of weighted deviates=1.8). This age is consistent with available geochronological data from volcanic rocks that host the mineralization and associated alteration phases. The high initial 187Os/188Os ratio indicates a lower crustal component for the source of Os and, by inference, the Cu sulfides that contain this Os. Late hematite occurs as an isolated phase or, more commonly, is associated with the chalcocite–bornite and supergene chalcocite–covellite associations. Analyses performed on pure hematite indicate a disturbance of the Re–Os system, and hence, this mineral phase is not useful as a Re–Os geochronometer. 相似文献
94.
Nguyen Dinh Duong Shoji Takeuchi 《ISPRS Journal of Photogrammetry and Remote Sensing》1997,52(6):253-260
The image analysis system ASEAN (Advanced System for Environmental ANalysis with Remote Sensing Data) was designed and programmed by a software development group, ImaSOFr, Department of Remote Sensing Technology and GIS, Institute for Geography, National Centre for Natural Science and Technology of Vietnam under technical cooperation with the Remote Sensing Technology Centre of Japan and financial support from the National Space Development Agency of Japan. ASEAN has been in continuous development since 1989, with different versions ranging from the simplest one for MS-DOS with standard VGA 320×200×256 colours, through versions supporting SpeedStar 1.0 and SpeedStar PRO 2.0 true colour graphics cards, up to the latest version named WinASEAN, which is designed for the Windows 3.1 operating system. The most remarkable feature of WinASEAN is the use of algorithms that speed up the image analysis process, even on PC platforms. Today WinASEAN is continuously improved in cooperation with NASDA (National Space Development Agency of Japan), RESTEC (Remote Sensing Technology Center of Japan) and released as public domain software for training, research and education through the Regional Remote Sensing Seminar on Tropical Eco-system Management which is organised by NASDA and ESCAR In this paper, the authors describe the functionality of WinASEAN, some of the relevant analysis algorithms, and discuss its possibilities of computer-assisted teaching and training of remote sensing. 相似文献
95.
Tomoaki Morishita Yoshito Ishida Shoji Arai Miki Shirasaka 《Geostandards and Geoanalytical Research》2005,29(1):107-122
To understand and/or avoid small-scale chemical heterogeneities within geological materials prepared as normal thin sections, in situ multiple trace element determination coupled with the simultaneous microscopic observation of the sample during analysis is preferable. We have examined fifty trace elements in thin (< 30 μm) layers of the NIST SRM 614 and 616 glass reference materials by LA-ICP-MS using different pit diameters and internal standard elements (Ca and Si). Compositional heterogeneities of Tl, Bi, As and Cd were found in NIST SRM 614 and 616 at the spatial resolution of ca. 10 0 μm. Except for these elements, the RSDs of six determinations for most elements were better than 10% in NIST SRM 614 when ablation diameters were < 50 μm. The measured concentrations for most elements in NIST SRM 614 and 616 agree with previous values in the literature at the 95% confidence level with the exception of W and Bi. New LA-ICP-MS data for K, As and Cd are also reported. The results support the view that the latest LA-ICP-MS is a powerful and flexible analytical technique for the determination of multiple ultra-trace element compositions in geological materials prepared as normal thin sections of the type that has been used for polarising optical microscopic observations since the end of the 19th century. 相似文献
96.
Metasomatized harzburgite xenoliths from Avacha volcano as fragments of mantle wedge of the Kamchatka arc: Implication for the metasomatic agent 总被引:6,自引:0,他引:6
Abstract Abundant peridotite xenoliths have been found in pyroclasitics of Avacha (Avachinsky) volcano, the south Kamchatka arc, Russia. They are mostly refractory harzburgite with or without clinopyroxene: the Fo of olivine and Cr/(Cr + Al) atomic ratio of spinel range from 91 to 92 and from 0.5 to 0.7, respectively. They are metasomatized to various extents, and the metasomatic orthopyroxene has been formed at the expense of olivine. The metasomatic orthopyroxene, free of deformation and exsolution, is characterized by low contents of CaO and Cr2 O3 . The complicated way of replacement possibly indicates low viscosity of the metasomatic agent, namely hydrous fluids released from the relatively cool slab beneath the south Kamchatka arc. This is a good contrast to the north Kamchatka arc, where the slab has been hot enough to provide slab-derived melts. High content of total orthopyroxene, 40 vol% on average, in metasomatized harzburgite from Avacha suggests silica enrichment of the mantle wedge, and is equivalent to some subcratonic harzburgite. Some subcratonic harzburgites therefore could have been formed by transportation of subarc metasomatized peridotites to a deeper part of the upper mantle. 相似文献
97.
We found extremely high-Mg# (=Mg/(Mg + total Fe) atomic ratio) ultramafic rocks in Avacha peridotite suite. All the high-Mg#
rocks have higher modal amounts of clinopyroxene than ordinary Avacha peridotite xenoliths, and their lithology is characteristically
heterogeneous, varying from clinopyroxenite through olivine websterite to pyroxene-bearing dunite. The Mg# of minerals is
up to 0.99, 0.98 and 0.97 in clinopyroxene, orthopyroxene and olivine, respectively, decreasing progressively toward contact
with dunitic part, if any. The petrographical feature of pyroxenes in the high-Mg# pyroxenite indicates their metasomatic
origin, and high LREE/HREE ratio of the metasomatic clinopyroxene implies that the pyroxenites are the products of reaction
between dunitic peridotites and high-Ca, silicate-rich fluids. The lithological variation of the Avacha high-Mg# pyroxenites
from clinopyroxenite to olivine websterite resulted from various degrees of fluid-rock reaction coupled with fractional crystallization
of the high-Ca fluids, which started by precipitation of high-Mg# clinopyroxene. Such fluids were possibly generated originally
at a highly reduced serpentinized peridotite layer above the subducting slab. The fluids can reach the uppermost mantle along
a shear zone as a conduit composed of fine-grained peridotite that developed after continent-ward asthenospheric retreats
from the mantle wedge beneath the volcanic front. The fluids are incorporated in mantle partial melts when the magmatism is
activated by expansion of asthenosphere to mantle wedge beneath the volcanic front. 相似文献
98.
East Asian summer monsoon simulation by a 20-km mesh AGCM 总被引:1,自引:0,他引:1
East Asian summer monsoon climate simulated by a global 20-km mesh atmospheric general circulation model (AGCM) forced by
the global sea surface temperature during the period 1979–1998 is investigated. In comparison with a lower resolution (180-km
mesh) model experiment, it is revealed that the 20-km mesh AGCM shows the superiority in simulating orographic rainfall not
only its location but also its amount. The Baiu frontal structure is also better simulated in the higher resolution model,
which leads to stronger Baiu rainfall. The 20-km model also shows more intense extremes in precipitation. Interannual variability
of June–August mean precipitation and seasonal march of the monsoon rain band are also investigated.
This paper is a contribution to the AMIP-CMIP Diagnostic Sub-project on General Circulation Model Simulation of the East Asian
Climate, coordinated by W.-C. Wang. 相似文献
99.
Junji Yamamoto Shun'ichi Nakai Koshi Nishimura Ichiro Kaneoka Hiroyuki Kagi Keiko Sato Tasuku Okumura Vladimir S. Prikhod'ko Shoji Arai 《Island Arc》2009,18(1):225-241
Based on both major and trace element chemistry, the occurrence of the intergranular component in mantle-derived xenoliths from far eastern Russia has been constrained. Whole-rock trace element measurements of one xenolith show apparent negative anomalies in Ce, Th, and high field strength elements on normalized trace element patterns. The trace element pattern of the whole rock differs from those of constituent minerals, indicating that the anomalies in the whole rock are attributable to the presence of an intergranular component. That assumption was confirmed using in situ analysis of trace elements in the intergranular substance and melt inclusion using laser ablation inductively coupled plasma–mass spectrometry. Both the intergranular component and the melt inclusions have identical trace element patterns, which mean that these materials are a cognate metasomatizing agent. The anomalies are regarded as mantle metasomatism related to an aqueous fluid. Hydrous minerals were observed on the wall of the melt inclusions using micro-Raman spectroscopy, indicating that the melt inclusions contained a large amount of water. Thus, this study reveals a trace element composition of a hydrous metasomatizing agent in the mantle. 相似文献
100.
Recent studies on mineralogy, geochronology, fluid inclusion and stable isotope (Pb, Os, S, C, O, Sr) characteristics were reviewed to determine constraints for genetic models of the Chilean manto‐type copper deposits. The Chilean manto‐type deposits are divided into the two geologic categories of the northern areas (Arica–Iquique, Tocopilla–Taltal) and the central areas (Copiapó, La Serena, Santiago). The former is distributed in the coastal range composed of Jurassic andesite‐dominated volcano‐sedimentary piles and younger plutonic intrusions, and yields chalcocite (‐digenite) and bornite as the principal hypogene copper sulfides. The latter is hosted mostly in Lower Cretaceous volcano‐sedimentary sequences, and has chalcopyrite‐rich mineral associations. The fluid inclusion data indicate that the primary copper mineralization was commonly generated in the temperature range 150–360°C under low‐pressure conditions near the boiling curve, mediated with relatively saline brines. Generally, homogeneous Pb and S isotope compositions for primary copper minerals imply direct magma source or leaching of igneous rocks. Pb and Os isotope data published for some deposits, however, suggest that ore‐forming metals were derived mainly from the volcano‐sedimentary host rocks. The noticeably negative isotope ratios of primary sulfide sulfur and hydrothermal calcite carbon of some central area deposits indicate influx of sedimentary rock components, and the high 87Sr/86Sr initial ratios of hydrothermal calcite from the Tocopilla–Taltal area deposits imply contribution of the contemporaneous seawater or marine carbonates. These isotopic constraints imply a formation mechanism in which the Chilean manto‐type copper deposits formed epigenetically in the process of hydrothermal interaction of non‐magmatic surface‐derived brine with the volcano‐sedimentary host rocks, which is inferred to have been induced by a deep‐seated plutonic complex as the possible heat source. 相似文献