全文获取类型
收费全文 | 227篇 |
免费 | 0篇 |
专业分类
测绘学 | 4篇 |
大气科学 | 9篇 |
地球物理 | 38篇 |
地质学 | 82篇 |
海洋学 | 60篇 |
天文学 | 18篇 |
综合类 | 2篇 |
自然地理 | 14篇 |
出版年
2021年 | 4篇 |
2019年 | 5篇 |
2018年 | 1篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 5篇 |
2013年 | 10篇 |
2012年 | 6篇 |
2011年 | 12篇 |
2010年 | 13篇 |
2009年 | 4篇 |
2008年 | 14篇 |
2007年 | 14篇 |
2006年 | 11篇 |
2005年 | 12篇 |
2004年 | 9篇 |
2003年 | 6篇 |
2002年 | 3篇 |
2001年 | 2篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 3篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 3篇 |
1994年 | 3篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 5篇 |
1989年 | 2篇 |
1988年 | 1篇 |
1987年 | 4篇 |
1986年 | 1篇 |
1985年 | 5篇 |
1984年 | 2篇 |
1983年 | 7篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1972年 | 1篇 |
1970年 | 1篇 |
1966年 | 1篇 |
1960年 | 1篇 |
排序方式: 共有227条查询结果,搜索用时 21 毫秒
171.
In order to clarify the structure of the strong tidal current at the Naruto Strait in the Seto Inland Sea of Japan, the sea-level values were observed in the strait and the current measurements were made with an Acoustic Doppler Current Profiler (ADCP).The tidal volume transports for M2 and S2 tides were about 74×103 and 26×103 m3 sec–1, respectively. The horizontal profile of the velocity at the phase of the strong tidal current compares favorably with a theoretical profile of the two-dimensional steady turbulent jet except for the side parts of the profile. Moreover, the entrainment rate of the surrounding water into the strong tidal jet was estimated from the difference of mass flux between two cross-sections at the strait, the entrainment rate and entrainment constant for both the northward and southward flows being about 1.3–2.5×10–4m–1 and about 0.03–0.05, respectively. 相似文献
172.
Sanae Chiba Tsuneo Ono Kazuaki Tadokoro Takashi Midorikawa Toshiro Saino 《Journal of Oceanography》2004,60(1):149-162
An analysis of the time series data sets collected from the 1960s to 1990s in the Oyashio Water revealed signs of alteration
in the physical, chemical and biological properties of the water column in the western subarctic North Pacific. Wintertime
salinity, phosphate concentration and apparent oxygen utilization (AOU) in the subsurface increased linearly over the 30 years.
At the same time, salinity and phosphate in the surface mixed layer decreased. An increase in the density gradient in the
surface and subsurface suggested that the water column stratification intensified, reducing the vertical exchange of water
properties during the period. The Net Community Production (NCP), estimated from the phosphate consumption from February through
August, also declined. Water column Chl a was approximately halved and diatoms decreased by one order of magnitude in spring, consistent with the multi-decadal decreasing
trend of NCP. Zooplankton biomass was also nearly halved during the same period. In contrast, wintertime Chl a increased by 63% and diatom abundance doubled. Developmental timing became earlier in Neocalanus flemingeri, and spring occurrence of N. plumchrus increased after the 1980s. Reduced vertical water exchange might have limited nutrient supply to the level, decreasing winter-summer
NCP for these three decades. It is speculated that, in the meantime, the earlier stabilization of the surface layer might
have enhanced wintertime diatom production in the Oyashio's light-limited environment. This condition could allow zooplankton
to effectively utilize diatoms from earlier timing, resulting in the apparent early developmental timing and abundance increase.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
173.
The behavior of transition metals (Co, Ni, Cu and Zn) on precipitation of manganese oxides from seawater pumped up from a
well at the site of the Marine Science Museum, Tokai University, and collected from several tanks along the water supply system
to an aquarium was investigated. The distribution coefficients of cobalt and nickel between manganese oxides and seawater
were different at different sampling points along the water supply system. At sampling points with high rates of manganese
oxide precipitation, the distribution coefficients were about one order of magnitude smaller than those at the points with
low precipitation rates, while there were no remarkable differences in the distribution coefficients of copper and zinc among
the sampling points. The distribution coefficients of minor transition metals, with the exception of copper, observed at the
points with low precipitation rates were comparable to those measured experimentally using manganese dioxides. 相似文献
174.
Atsushi Tsuda Hiroshi Kiyosawa Akira Kuwata Mamiko Mochizuki Naonobu Shiga Hiroaki Saito Sanae Chiba Keiri Imai Jun Nishioka Tsuneo Ono 《Progress in Oceanography》2005,64(2-4):189
Phytoplankton species composition was analyzed inside and outside of the iron-enriched patch during the SEEDS experiment. Before the iron-enrichment, the phytoplankton community consisted of similar proportions of pico-, nano- and micro-sized phytoplankton, and the micro-phytoplankton was dominated by the pennate diatom Pseudo-nitzschia turgidula. Although all the diatoms, except the nano-sized Fragilariopsis sp., increased during the two weeks of the observation period, the flora in the patch dramatically changed with the increase of phytoplankton biomass to a centric diatom-dominated community. Neritic diatoms, especially Chaetoceros debilis, showed higher growth rates than other diatoms, without any delay in the initiation of growth after the enrichment, and accounted for 90% of the micro-phytoplankton after day 9. In contrast, the oceanic diatoms showed distinct delays in the initiation of growth. We conclude that the responses of the diatoms to the manipulation of iron concentration were different by species, and the fast and intensive response of the phytoplankton to iron-enrichment resulted from the presence of a small amount of neritic diatoms at the study site. The important factors that determine the dominant species in the bloom are the potential growth rates under an iron-replete condition and the growth lag. Abundant species in the patch are widely distributed in the North Pacific and their relative contributions in the Oyashio area and at Stn KNOT are high from spring to summer. However, a characteristic difference of species composition between the SEEDS bloom and natural blooms was the lack of Thalassiosira and Coscinodiscus species in the patch, which usually account for a major part of the phytoplankton community under blooming conditions in the western North Pacific. 相似文献
175.
Yoshio Sato 《Journal of Oceanography》1989,45(4):270-278
At the Minamichita Beach Land (Mihama-cho, Aichi, Japan), seawater is pumped up from underground and is supplied to aquaria. The underground seawater containsca. 2 ppm of Fe (II), 0.1 ppm of Mn (II) and a little dissolved oxygen. Iron oxide is formed in the seawater when aerated. The oxidation rate of Fe (II) was measured to be 1.4×1014 mol–3
l
3 min–1, which is comparable to the lowest values in the literature. The slow rate of Fe (II) oxidation obtained here can be attributed to the presence of organically bound iron in the seawater. The distribution coefficient of cations between seawater and iron oxide phase was in the order of Cu>Ni>Co>Cd>Mn, which is consistent with that predicted from their hydrolysis constants. The adsorption affinity sequence of oxyanions was phosphate >vanadate> molybdate. The difference in phosphate from the prediction of the adsorption theory was attributed to the formation of ferriphosphate on the oxide surface. On the basis of these data, the limitation and usefulness in the application of the distribution coefficients to marine environments were discussed. 相似文献
176.
Sources of systematic error in the sampling procedure by Winkler method were examined. In the laboratory experiment, the dissolution of atmospheric oxygen into oxygenfree sea water during sampling amounts to 0.022 ml/l, and the effect of dissolved oxygen in sea water remaining in oxygen bottle is 0.019 ml/l. The effect of reagents added amounts to 0.017 ml/l. In the sampling procedures aboard, the effect of dissolution became bigger, and the table is presented for the correction to the reported value of dissolved oxygen measured by the “Manual of Oceanographic Observation”. The corrected value of dissolved oxygen in the routine analysis may not be correct within 0.02 ml/l. 相似文献
177.
178.
Yoshio Kubo 《Celestial Mechanics and Dynamical Astronomy》1982,26(1):97-112
Perturbations in the motion of the Moon are computed for the effect by the oblateness of the Earth and for the indirect effect of planets. Based on Delaunay's analytical solution of the main problem, the computations are performed by a method of Fourier series operation. The effect of the oblateness of the Earth is obtained to the second order, partly adopting an analytical evaluation. Both in longitude and latitude are found a few terms whose coefficient differs from the current lunar ephemeris based on Brown's theory by about 0.01. While, concerning the indirect effect of planets, several periodic terms in the current ephemeris seem to have errors reaching 0.05.As for the secular variations of
and due to the figure of the Earth and the indirect effect of planets, the newly-computed values agree within 1/cy with Brown's results reduced to the same values of the parameters. Further, the accelerations in the mean longitude,
and caused by the secular changes in the eccentricity of the Earth's orbite and in the obliquity of the ecliptic are obtained. The comparison with Brown shows an agreement within 0.3/cy2 for the former cause and 0.02/cy2 for the latter. An error is found in the argument of the principal term for the perturbations due to the ecliptic motion in the current ephemeris.Proceedings of the Conference on Analytical Methods and Ephemerides: Theory and Observations of the Moon and Planets. Facultés universitaires Notre Dame de la Paix, Namur, Belgium, 28–31 July, 1980. 相似文献
179.
Yusuke Miyajima Ayaka Saito Hiroyuki Kagi Tatsunori Yokoyama Yoshio Takahashi Takafumi Hirata 《Geostandards and Geoanalytical Research》2021,45(1):189-205
Uncertainty for elemental and isotopic measurements in calcite by LA‐ICP‐MS is largely controlled by the homogeneity of the reference materials (RMs) used for calibration and validation. In order to produce calcite RMs with homogeneous elemental and isotopic compositions, we incorporated elements including U, Pb and rare earth elements into calcite through heat‐ and pressure‐induced crystallisation from amorphous calcium carbonate that was precipitated from element‐doped reagent solution. X‐ray absorption spectra showed that U was present as U(VI) in the synthesised calcite, probably with a different local structure from that of aqueous uranyl ions. The uptake rate of U by our calcite was higher in comparison with synthetic calcite of previous studies. Variations of element mass fractions in the calcite were better than 12% 2RSD, mostly within 7%. The 207Pb/206Pb ratio in the calcite showed < 1% variations, while the 238U/206Pb ratio showed 3–24% variations depending on element mass fractions. Using the synthetic calcite as primary RMs, we could date a natural calcite RM, WC‐1, with analytical uncertainty as low as < 3%. The method presented can be useful to produce calcite with controlled and homogeneous element mass fractions and is a promising alternative to natural calcite RMs for U‐Pb geochronology. 相似文献
180.
To clarify the generation and dissipation mechanisms of diurnal coastal-trapped waves (CTWs) over the Sakhalin shelf, a series of numerical experiments were conducted using a three-dimensional tidal model of the Okhotsk Sea with density stratification. The tidal model used has good reproduction owing to the careful fitting to the recent observations. The numerical experiments suggested that diurnal CTWs are primarily (~60%) generated by the conversion of tidal energy at the northern corner of the Sakhalin shelf, and further amplified by vorticity generation due to the water column oscillation from Sakhalin Bay and the influence of Kashevarov Bank. From the observations, it was found that diurnal CTWs are effectively dissipated by the strong spin-down due to bottom friction. The conventional turbulent closure model cannot reproduce the observed damping of diurnal CTWs, which raises a caution in modeling the tidal fields in high-latitude regions where diurnal CTWs exist. To resolve this underestimation of the damping, the vertical eddy viscosity was parameterized using its dependence on the observed major axis length of the diurnal tidal current ellipses, which improves the model reproduction on the damping of diurnal CTWs. The model also suggests that the spin-down effects due to friction associated with the sea-ice cover play an important role in the tidal current reduction in the region where diurnal CTWs exist, as the observations suggested. 相似文献