全文获取类型
收费全文 | 83篇 |
免费 | 2篇 |
国内免费 | 2篇 |
专业分类
大气科学 | 7篇 |
地球物理 | 17篇 |
地质学 | 17篇 |
海洋学 | 14篇 |
天文学 | 30篇 |
自然地理 | 2篇 |
出版年
2022年 | 1篇 |
2021年 | 2篇 |
2017年 | 2篇 |
2016年 | 2篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 2篇 |
2012年 | 4篇 |
2011年 | 1篇 |
2010年 | 2篇 |
2009年 | 8篇 |
2008年 | 6篇 |
2007年 | 1篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 8篇 |
2002年 | 6篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 2篇 |
1998年 | 3篇 |
1995年 | 1篇 |
1992年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1974年 | 5篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
排序方式: 共有87条查询结果,搜索用时 343 毫秒
21.
Abundance and diversity of fungi in relation to chemical changes in arctic moss profiles 总被引:1,自引:1,他引:0
Mosses are a dominant component of high-arctic terrestrial ecosystems, yet little is known regarding the abundance and diversity of fungi associated with these abundant plants. We investigated vertical patterns of abundance and diversity of fungi and their relationship with chemical properties within profiles of Hylocomium splendens and Racomitrium lanuginosum collected in the Oobloyah Bay area on Ellesmere Island, Canada. The moss profiles were divided into 6 (H. splendens) and 5 (R. lanuginosum) layers according to the color and texture, and hyphal length, fungal assemblages, and contents of organic chemical components (acid-unhydrolyzable residues, total carbohydrates, extractives) and nutrients (N, P, K, Ca, Mg) were measured. Total hyphal length was greatest at the middle layers of H. splendens and at the deepest layers of R. lanuginosum and was significantly affected by moss species and nutrient contents. A total of 18 and 19 fungal taxa was isolated from the profiles of H. splendens and R. lanuginosum, respectively, with 11 taxa being common to both moss species. Moss species significantly affected the species distribution of fungi. Individual fungal taxa showed patterns of vertical distribution within the moss profiles. The contents of acid-unhydrolyzable residues and nutrients increased and the content of total carbohydrates decreased down the profile, which was attributable to the ability of fungi to decompose carbohydrates selectively and to immobilize nutrients in decomposed moss residues. 相似文献
22.
Early Permian ammonoids from the Kaeng Krachan Group of the Phatthalung-Hat Yai area, southern peninsular Thailand 总被引:1,自引:1,他引:1
Masayuki Fujikawa Katsumi Ueno Apsorn Sardsud Wirote Saengsrichan Yoshihito Kamata Ken-ichiro Hisada 《Journal of Asian Earth Sciences》2005,24(6):739
An Early Permian small ammonoid fauna consisting of Neocrimites sp., Agathiceras suessi Gemmellaro, A. girtyi Böse, Agathiceras? sp., and Miklukhoceras sp. was found in nodules of a fine sandstone bed exposed in the Phatthalung-Hat Yai area of southern peninsular Thailand. The ammonoid-bearing bed belongs stratigraphically to the uppermost part of the Kaeng Krachan Group, which is essentially a clastic-dominant, Late Carboniferous (?) to Early Permian stratigraphic unit, widely distributed in western and peninsular Thailand. This ammonoid fauna is considered to be of Bolorian (Kungurian) age and includes Agathiceras girtyi Böse, which is described for the first time from Thailand. The present discovery of Bolorian ammonoids suggests that the uppermost part of the Kaeng Krachan Group is slightly younger than previously considered and around the latest Early Permian. This further implies that the continental margin environment of the Sibumasu Block drastically changed at around Bolorian time from a cool, clastic-dominant shelf condition to a temperate to subtropical, carbonate platform due to rapid northward drift after middle Artinskian rifting. 相似文献
23.
Summary ?This paper describes a numerical study of the major spiral rainband in typhoon Flo (1990) using the Meteorological Research
Institute Mesoscale Nonhydrostatic Model (MRI-NHM). The effects of precipitation schemes and horizontal resolution on the
representation of the simulated rainband are discussed.
Dynamic and thermodynamic structures of the simulated major rainband to the north of the storm center are well represented
in the model with a 5 km horizontal resolution. The structures are consistent with observational results reported for other
tropical cyclones. Among the realistic features are: a cold pool and convergence on the inner side of the band; convergence
above low-level inflow layers; and the outward slope of the updraft with height. The band is caused by the motion of the storm
through its surroundings where horizontal wind has vertical shear.
The simulation of the structure and precipitation pattern associated with the major rainband depends on the precipitation
scheme rather than the horizontal resolution. The band appears more realistic when using explicit cloud microphysics as a
precipitation scheme, rather than moist convective adjustment. This result is attributable to the difference in scheme triggering.
In the simulation with moist convective adjustment, the elimination of vertical instability in low-level atmosphere is excessive,
suppressing band formation. The overall structure of the band is also more realistic in the simulation using explicit cloud
microphysics, because a cold pool exists in the lower layers and the vertical axis of upward flow tilts outward. This result
suggests that prediction will partly depend on variables associated with cloud microphysics, such as the mixing ratio of cloud
water.
The horizontal grid distance, which varied between 5 and 20 km, quantitatively influenced the rainfall amount, although the
large-scale band structure remained unchanged. The rainfall amount increased as the grid interval was reduced from 20 to 10-km
but decreased as the interval was further reduced from 10 to 5 km.
Received March 20, 2001; revised August 20, 2001 相似文献
24.
Abstract. A detail investigation of ore and gangue minerals was performed on the Doyashiki Kuroko deposits, Hokuroku basin, Japan for the first time. Main ore minerals are sphalerite, galena, pyrite, chalcopyrite, tetrahedrite-tennantite and digen-ite. Small amounts of enargite, wittichenite, electrum, covellite, bornite, marcasite and hematite are also observed. Quartz, barite and gypsum are common gangue minerals. Homogenization temperatures and salinities of fluid inclusions in quartz, sphalerite and barite range from 190 to 240C and 3.0 to 5.5 wt% NaCl equivalent, respectively. The FeS contents of sphalerite and Ag contents of electrum were 0.12 to 0.18 mol %, 39.0 to 39.6 atom %, respectively. The chemical composition of digenite as a primary mineral shows high sulfur contents.
These data indicate that ore fluid responsible for digenite and associated ore minerals was characterized by a range of high sulfur fugacity with a moderate formation temperature. This is concordant with the mineral assemblage of bornite-pyrite and chalcopyrite, which shows high sulfur fugacity conditions. It seems that the mineralization closely associated with acidic volcanism has occurred around 13 Ma of Middle Miocene on the seafloor at the depth of about 1500 m. 相似文献
These data indicate that ore fluid responsible for digenite and associated ore minerals was characterized by a range of high sulfur fugacity with a moderate formation temperature. This is concordant with the mineral assemblage of bornite-pyrite and chalcopyrite, which shows high sulfur fugacity conditions. It seems that the mineralization closely associated with acidic volcanism has occurred around 13 Ma of Middle Miocene on the seafloor at the depth of about 1500 m. 相似文献
25.
K-Ar Ages of Tin-Polymetallic Mineralization in the Oruro Mining District, Central Bolivian Tin Belt 总被引:2,自引:0,他引:2
Abstract. K-Ar age determinations were carried out on vein- and rock-forming minerals from five vein-type tin-polymetallic ore deposits of the Oruro mining district in the central part of the Bolivian tin belt. The sericite from vein selvedges and an altered host rock provides good estimates of the ages of hypogene mineralization, and supergene alunite and jarosite provide ages for erosional and weathering episodes. It is concluded that hypogene mineralization in the Oruro mining district took place during the early to middle Miocene: 15.8±0.8 Ma at San José, 20.1±l.l Ma at Morococala, 20.5±1.0 Ma at Avicaya, and 19.6±1.0 Ma at Llallagua. Fine grained supergene alunite (δ34 S = -10.1 960) and jarosite yield K-Ar ages of 6.7±0.7 Ma at Avicaya and 3.9±0.7 Ma at Bolivar, respectively, suggesting that erosion and chemical weathering were active at those times. 相似文献
26.
S. Ueno 《Astrophysics and Space Science》1976,44(1):151-158
In a series of our preceding papers (cf. Bellman and Ueno, 1971a, 1971b, 1972a, 1972b, 1972c; Ueno 1972), with the aid of invariant imbedding technique, we transformed the two point boundary value problem for integral equations into the initial-value problem. In this paper, extending the procedure to the Milne's integral equation, whose kernel is expanded into a double Fourier cosine series, we show how to find a Cauchy system for the required solution of Milne's integral equation and the Fredholm resolvent. The obtained integro-differential equations are reduced to large system of ordinary differential equations with known initial conditions. Then, they are suitable for the numerical computation of the solution by the modern high-speed computer. 相似文献
27.
S. Ueno 《Astrophysics and Space Science》1974,30(1):27-34
In a manner similar to that given in a preceding paper (cf. Castiet al., 1970), in this paper we show how to get a Cauchy system for the scattering and transmission matrices of the azimuth-independent term of partially polarized light in accordance with Rayleigh scattering in a homogeneous atmosphere bounded by a specular reflector. This set of integro-differential equations for the scattering and transmission matrices is suitable for numerical computation by high-speed digital computer. 相似文献
28.
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
29.
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
30.