全文获取类型
收费全文 | 252篇 |
免费 | 3篇 |
国内免费 | 2篇 |
专业分类
测绘学 | 5篇 |
大气科学 | 6篇 |
地球物理 | 68篇 |
地质学 | 47篇 |
海洋学 | 94篇 |
天文学 | 27篇 |
综合类 | 1篇 |
自然地理 | 9篇 |
出版年
2021年 | 2篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 7篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 7篇 |
2013年 | 13篇 |
2012年 | 3篇 |
2011年 | 12篇 |
2010年 | 7篇 |
2009年 | 7篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 8篇 |
2005年 | 11篇 |
2004年 | 6篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 16篇 |
1999年 | 3篇 |
1998年 | 5篇 |
1997年 | 2篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1993年 | 2篇 |
1992年 | 6篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 4篇 |
1987年 | 1篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 8篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 4篇 |
1976年 | 4篇 |
1975年 | 4篇 |
1974年 | 6篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 2篇 |
1970年 | 2篇 |
排序方式: 共有257条查询结果,搜索用时 15 毫秒
1.
A formulation for the aerodynamic roughness length of air flow over wind waves $$z_0 = \gamma {\text{ }}u_* /\sigma p$$ which was proposed by Toba (1979) and Toba and Koga (1986) from dimensional considerations with some data analysis, is shown to correspond with a formulation for irregular solid surfaces $$(z_0 /h) = a(h/l)^{1 + \beta } $$ which resulted from work by Woodinget al. (1973) and Kustas and Brutsaert (1986);u * is the friction velocity,σ p the spectral peak frequency of wind waves,h the mean height of the solid obstacles,l the mean distance between their crests, andα,Β, andγ are constants. This correspondence is reached by the existence of a statistical 3/2-power law and an effective dispersion relationship for wind waves. Because both approaches of parameterizingz 0 were arrived at independently, they provide each other mutual reinforcement. 相似文献
2.
A method for the prediction of ocean waves was developed on the basis of the single-parameter growth equation of wind waves, proposed byToba (1978) on the basis of similarity in growing wind waves. The applicability of the method to actual problems was tested by hindcasting the wave characteristics with the method, for two cases with differing time and space scales, one in Kii Channel Approach, Japan, and the other in the North Atlantic Ocean. The results showed that the present method can predict waves within an error of 1.3 m in wave heights, which ranged from 3 to 12 m. 相似文献
3.
Least-squares prediction using an empirically deduced local covariance function was performed to investigate the temporal
change in the rates of vertical crustal movements in the Tohoku district, Japan. Levelling data covering an area of approximately
450 × 275 km2 observed between 1966 and 1995 were used and the results shown in the form of contour maps. Firstly we derived a covariance
function of the rates of vertical crustal movement with a Gaussian form function. We used this function to estimate the spatial
distribution of the rates of vertical crustal movements. By the present method, a steady tilt of the Tohoku district to the
east, toward the Japan Trench and an areal uplift in the southwestern part were well reproduced. Moreover, a significant temporal
change in vertical movement rates is clearly seen.
Received: 15 July 1996 相似文献
4.
Nondimensionalization of variables enables us to treat experiment data much more simply and efficiently by decreasing the
number of variables. In some cases, trivial conclusions (which Kenney, 1982, called spurious self-correlation) result from
a formal application of dimensional analyses. In contrast, in some cases fully significant conclusions can be derived. We
first discuss how to construct nondimensional variables retaining the physical meanings of variables. We then propose simple
and efficient methods, especially the use of “spurious triangle (SpT)”, to discriminate between significant conclusions and
spurious self-correlations in the analysis of nondimensionalized variables. 相似文献
5.
Masahiko Fujii Fei Chai Lei Shi Hisayuki Y. Inoue Masao Ishii 《Journal of Oceanography》2009,65(5):689-701
The oceanic carbon cycle in the tropical-subtropical Pacific is strongly affected by various physical processes with different
temporal and spatial scales, yet the mechanisms that regulate air-sea CO2 flux are not fully understood due to the paucity of both measurement and modeling. Using a 3-D physical-biogeochemical model,
we simulate the partial pressure of CO2 in surface water (pCO2sea) and air-sea CO2 flux in the tropical and subtropical regions from 1990 to 2004. The model reproduces well the observed spatial differences
in physical and biogeochemical processes, such as: (1) relatively higher sea surface temperature (SST), and lower dissolved
inorganic carbon (DIC) and pCO2sea in the western than in the central tropical-subtropical Pacific, and (2) predominantly seasonal and interannual variations
in the subtropical and tropical Pacific, respectively. Our model results suggest a non-negligible contribution of the wind
variability to that of the air-sea CO2 flux in the central tropical Pacific, but the modeled contribution of 7% is much less than that from a previous modeling
study (30%; McKinley et al., 2004). While DIC increases in the entire region SST increases in the subtropical and western tropical Pacific but decreases
in the central tropical Pacific from 1990 to 2004. As a result, the interannual pCO2sea variability is different in different regions. The pCO2sea temporal variation is found to be primarily controlled by SST and DIC, although the role of salinity and total alkalinity,
both of which also control pCO2sea, need to be elucidated by long-term observations and eddy-permitting models for better estimation of the interannual variability
of air-sea CO2 flux. 相似文献
6.
More than 30 years of chemical oxygen demand (COD) and dissolved inorganic nitrogen (DIN) data for the inner area of the Ariake Sea were analyzed with a box model to show the changes in the average seasonal budget and the decadal-scale variation during the summer. The COD peaked in August and March on average. This summertime peak can be explained by an enhanced riverine load and increased primary production. The peak in March suggested additional organic matter production. There were also two peaks in DIN concentration on average: a summertime peak that could be explained by an enhanced riverine load, and a peak in December that was more complicated to explain. From the 1970s to the early 1990s, the bottom water in this area became increasingly hypoxic due to increased COD during the summer, even though there were minimal increases in terrestrial COD and nutrient loads and there were tidal flats covering a widespread area during this period. The increase in COD was caused by increased net ecosystem production, which was due to enhanced primary production induced by an increased freshwater residence time and decreased bivalve grazing. There was a negative feedback control in which hypoxia progressively increased, leading to declines in bivalve biomass, which in turn decreased the grazing pressure limiting primary production, meaning that primary production increased and the area became even more hypoxic. The net DIN production decreased during the 1980s and the 1990s. This was consistent with the change in net ecosystem production according to the COD. 相似文献
7.
Frédéric Moynier Toshiyuki Fujii Kun Wang Julien Foriel 《Comptes Rendus Geoscience》2013,345(5-6):230-240
Iron is one of the most abundant transition metal in higher plants and variations in its isotopic compositions can be used to trace its utilization. In order to better understand the effect of plant-induced isotopic fractionation on the global Fe cycling, we have estimated by quantum chemical calculations the magnitude of the isotopic fractionation between different Fe species relevant to the transport and storage of Fe in higher plants: Fe(II)-citrate, Fe(III)-citrate, Fe(II)-nicotianamine, and Fe(III)-phytosiderophore. The ab initio calculations show firstly, that Fe(II)-nicotianamine is ~3‰ (56Fe/54Fe) isotopically lighter than Fe(III)-phytosiderophore; secondly, even in the absence of redox changes of Fe, change in the speciation alone can create up to ~1.5‰ isotopic fractionation. For example, Fe(III)-phytosiderophore is up to 1.5‰ heavier than Fe(III)-citrate2 and Fe(II)-nicotianamine is up to 1‰ heavier than Fe(II)-citrate. In addition, in order to better understand the Fe isotopic fractionation between different plant components, we have analyzed the iron isotopic composition of different organs (roots, seeds, germinated seeds, leaves and stems) from six species of higher plants: the dicot lentil (Lens culinaris), and the graminaceous monocots Virginia wild rye (Elymus virginicus), Johnsongrass (Sorghum halepense), Kentucky bluegrass (Poa pratensis), river oat (Uniola latifolia), and Indian goosegrass (Eleusine indica). The calculations may explain that the roots of strategy-II plants (Fe(III)-phytosiderophore) are isotopically heavier (by about 1‰ for the δ56Fe) than the upper parts of the plants (Fe transported as Fe(III)-citrate in the xylem or Fe(II)-nicotianamine in the phloem). In addition, we suggest that the isotopic variations observed between younger and older leaves could be explained by mixing of Fe received from the xylem and the phloem. 相似文献
8.
Design and Long-Term Monitoring of Tokyo International Airport Extension Project Constructed on Super-Soft Ground 总被引:1,自引:0,他引:1
K. Morohoshi K. Yoshinaga M. Miyata I. Sasaki H. Saitoh M. Tokoro N. Fukuda T. Fujii K. Yamada M. Ishikawa 《Geotechnical and Geological Engineering》2010,28(3):223-232
To meet the increasing demand for air transportation, Ministry of Land, Infrastructure and Transport had carried out the offshore
extension project at Tokyo International Airport (Haneda Airport). The airport should be constructed to be perfectly level,
but the ground conditions with very thick layers of super soft dredged soils and need for reclamation made the task very difficult.
Because of large amount of consolidation settlement, ground improvement by combined vertical drain method was applied to decrease
residual and differential settlement after opening of new airport. This paper is aimed to introduce the design concept and
method of ground improvement for this project. In addition the result of ground improvement is keeping satisfactory performance
for operating airport confirmed by long-term monitoring for airport facilities. 相似文献
9.
Satoshi Noguchi Naoyuki Shimoda Osamu Takano Nobutaka Oikawa Takao Inamori Tatsuo Saeki Tetsuya Fujii 《Marine and Petroleum Geology》2011,28(10):1817-1828
The reservoir architecture of methane hydrate (MH) bearing turbidite channels in the eastern Nankai Trough, offshore Japan is evaluated using a combination of 3-D seismic and well data. On the 3-D seismic section, the MH-bearing turbidite channels correspond to complex patterns of strong seismic reflectors, which show the 3-D internal architecture of the channel complex. A seismic-sequence stratigraphic analysis reveals that the channel complex can be roughly classified into three different stages of depositional sequence (upper, middle, and lower). Each depositional sequence results in a different depositional system that primarily controls the reservoir architecture of the turbidite channels. To construct a 3-D facies model, the stacking patterns of the turbidite channels are interpreted, and the reservoir heterogeneities of MH-bearing sediments are discussed. The identified channels at the upper sequence around the β1 well exhibit low-sinuosity channels consisting of various channel widths that range from tens to several hundreds of meters. Paleo-current flow directions of the turbidite channels are typically oriented along the north-northeast-to-south-southwest direction. High-amplitude patterns were identified above the channels along the north-to-south and north-northeast-to-south-southeast directions. These roughly coincide with the paleo-current flow of the turbidite channels. An interval velocity using high-density velocity analysis shows that velocity anomalies (>2000 m/s) are found on the northeastern side of the turbidite channels. The depositional stage of the northeastern side of the turbidite channels exhibits slightly older sediment stages than the depositional stages of the remaining channels. Hence, the velocity anomalies of the northeastern side of the channels are related to the different stages of sediment supply, and this may lead to the different reservoir architectures of the turbidite channels. 相似文献
10.
Norihisa?UsuiEmail author Shiro?Ishizaki Yosuke?Fujii Masafumi?Kamachi 《Journal of Oceanography》2011,67(3):253-262
We assess validity of a Gaussian error assumption, the basic assumption in data assimilation theory, and propose two kinds
of constraints regarding non-Gaussian statistics. In the mixed water region (MWR) off the east coast of Japan exhibiting complicated
frontal structures, a probability density function (PDF) of subsurface temperature shows double peaks corresponding to the
Kuroshio and Oyashio waters. The complicated frontal structures characterized by the temperature PDF sometimes cause large
innovations, bringing about a non-Gaussianity of errors. It is also revealed that assimilated results with a standard three-dimensional
variational (3DVAR) scheme have some issues in MWR, arising from the non-Gaussianity of errors. The Oyashio water sometimes
becomes unrealistically cold. The double peaks seen in the observed temperature PDF are too smoothed. To improve the assimilated
field in MWR, we introduce two kinds of constraints, J
c1 and J
c2, which model the observed temperature PDF. The constraint J
c1 prevents the unrealistically cold Oyashio water, and J
c2 intends to reproduce the double peaks. The assimilated fields are significantly improved by using these constraints. The
constraint J
c1 effectively reduces the unrealistically cold Oyashio water. The double peaks in the observed temperature PDF are successfully
reproduced by J
c2. In addition, not only subsurface temperature but also whole level temperature and salinity (T–S) fields are improved by
adopting J
c1 and J
c2 to a multivariate 3DVAR scheme with vertical coupled T–S empirical orthogonal function modes. 相似文献