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171.
The effect of the earth's rotation on the behavior of heated water discharged from gigantic nuclear power plants was investigated numerically. It is shown that the effect is significant even for the existing scale of discharge. Horizontal spreading of the heated water is suppressed in offshoreward and northward directions (when heated water is discharged in an eastward direction from a westfacing coast in the northern hemisphere), but accelerated in the southward direction, and the shape of the formed warm water region becomes asymmetric. In this paper, several calculations were done using exaggerated Coriolis parameters (f) in order to demonstrate the effect of the earth's rotation. An increase off enhances above effect, but the situation of the inner region of the produced warm water mass is much different from that in the outer region near its margin. The southward expansion of surface isothermal contours in the inner region increases with an increase inf, but those in the outer region do not. This results in an increase of the sharpness of the front which is generated near the southern edge of the warm water region. We have not found simple parameters which describe the temperature and velocity distributions in the warm water mass produced. 相似文献
172.
Christopher L. Sabine Richard A. Feely Yutaka W. Watanabe Marilyn Lamb 《Journal of Oceanography》2004,60(1):5-15
The recent changes in the North Pacific uptake rate of carbon have been estimated using a number of different techniques over
the past decade. Recently, there has been a marked increase in the number of estimates being submitted for publication. Most
of these estimates can be grouped into one of five basic techniques: carbon time-series, non-carbon tracers, carbon tracers,
empirical relationships, and inverse calculations. Examples of each of these techniques as they have been applied in the North
Pacific are given and the estimates summarized. The results are divided into three categories: integrated water column uptake
rate estimates, mixed layer increases, and surface pCO2 increases. Most of the published values fall under the water column integrated uptake rate category. All of the estimates
varied by region and depth range of integration, but generally showed consistent patterns of increased uptake from the tropics
to the subtropics. The most disagreement between the methods was in the sub-arctic Pacific. Column integrated uptake rates
ranged from 0.25 to 1.3 mol m−2yr−1. The mixed layer uptake estimates were much more consistent, with values of 1.0–1.3 μmol kg−1yr−1 based on direct observations and multiple linear regression approaches. Surface pCO2 changes showed the most obvious regional variability (0.5–2.5 μatm yr−1) reflecting the sensitivity of these measurements to differences in the physical and biological forcing. The different techniques
used to evaluate the changes in North Pacific carbon distributions do not completely agree on the exact magnitude or spatial
and temporal patterns of carbon uptake rate. Additional research is necessary to resolve these issues and better constrain
the role of the North Pacific in the global carbon cycle.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
173.
By using data obtained at about 120 XBT stations, cold water regions in the vicinity of the shoal, Kokushô-sone (30°00N, 128°30E), which is located in the current zone of the Kuroshio in the East China Sea, were investigated.The temperature cross-sections obtained were compared with corresponding cross-sections obtained from the four former cruises which were already reported. On the present cruise forced upwelling area was found along the south slope of the shoal, instead of the north slope as was found on the former cruises.The area of the cold water region found along the south slope tends to decrease with decrease in depth, and at depths shallower than 250 m the cold water region extends northward passing the shoal. The area at a depth of 400 m is comparable to that of the shoal itself, and is about 35 km2.Physical parameters and their scales which seem to be related to the dynamics near the shoal are given in the Appendix. 相似文献
174.
Concentrations and inventories of137Cs and239,240Pu were determined in sea waters and sediments columns from the western North Pacific from 1980 to 1986.The239,240Pu/137Cs activity ratio in the water column shows a tendency to increase from the surface (10–3) to bottom waters (10–1), but the ratio in sediment is within a rather narrow range (10–2 to 10–1), indicating more effective removal of plutonium from the water column than137Cs. In regions south of 40N, the radionuclide inventories in the water column significantly exceed the estimated global fallout (stratospheric fallout due to the atmospheric nuclear explosion), especially in the case of239,240Pu. These excess inventories imply that local or close-in fallout derived from nuclear explosions in the equatorial North Pacific are well-preserved and retained in the regions, despite about 20 years since the atmospheric nuclear explosion moratorium. Data suggesting lateral transport of137Cs in surface water from north of 40N to southern regions is shown. Some data on90Sr contents are also shown. 相似文献
175.
In a previous paper (Oguma and Nagata, 2002), it was shown that frequency distributions of temperature and salinity in the
sea off Sanriku Coast, Japan are skewed, and sometimes observed values exceed m + 5σ (m = mean, σ = standard deviation). This means that, if we apply a 3σ criterion for a range check, many real data would be lost.
We have expanded our analysis to the subarctic North Pacific, the subarctic North Atlantic and their surrounding areas, by
computing the distributions of skewness and kurtosis. It is found that the region of high positive skewness extends in an
east-north-east direction in the Mixed Water Region from off Sanriku, and reaches to about 155°E. A high negative skewness
zone is recognized along the southern margin of the Kuroshio Extension. These are thought to be generated by the breaking
of the meander of the Kuroshio Extension and subsequent ejection of warm and cold eddies to the north and south, respectively.
Other high positive skewness areas are found to the south of Kuril Islands and in the Japan Sea. These are generated due to
very sharp vertical gradients of temperature and salinity. The situation in the North Atlantic is very similar to the North
Pacific, though the detailed nature is changed due to differences of oceanographic condition. The effect of grid size on the
skewed nature of the distribution is also discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
176.
177.
Ryuichiro Inoue Jiro Yoshida Yutaka Hiroe Kousei Komatsu Kiyoshi Kawasaki Ichiro Yasuda 《Journal of Oceanography》2003,59(2):211-224
The mixing processes in the Mixed Water Region (MWR) that lead to changes in the properties of North Pacific Intermediate
Water (NPIW) have been studied using observational data sets obtained in May–June 1998. Neutral surfaces, the equation of
water mass conversion rate on neutral surfaces and the equation of vertical velocity across neutral surfaces have been used
to distinguish dominant processes by assuming the horizontal scale to be the streamer scale (under 100 km). The possibility
of double diffusive convection is also discussed in relation to the density ratio. These results may be summarized as follows:
(1) the difference between the potential density surface and the neutral surface may rise to −0.04 kg/m3 around the source water of NPIW; (2) horizontal diffusion causes strong modifications of the source water of NPIW; (3) the
density range within which strong modification of the source water of NPIW occurs becomes dense from the northern part of
MWR near the Oyashio Front to the southern part near the Kuroshio Front, and to the eastern part. Our modeling of these processes
shows that cabbeling has effects on the density increment of the source water of NPIW in the northern and southern part of
MWR. Double diffusive convection has effects on the density increment of the source water of NPIW, mainly in the northern
part of MWR. The possible density increment due to cabbeling in these areas is estimated to be 0.01≈0.03 kg/m3. The possible density increment due to double diffusive convection is 0.01≈0.03 kg/m3. The total density increment due to cabbeling and double diffusive convection amounts to 0.06 kg/m3.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
178.
Yoshiro Watanabe Yutaka Kurita Masayuki Noto Yoshioki Oozeki Daiji Kitagawa 《Journal of Oceanography》2003,59(4):403-414
Growth and mortality rates of larval and early juvenile Pacific saury Cololabis saira were estimated for spring and autumn spawning seasons in the Kuroshio-Oyashio transitional waters and for winter spawning
season in the Kuroshio waters in 9 years from 1990–1998, based on quantitative fish sampling and otolith daily ring readings.
Growth and mortality rates were more variable in the Kuroshio-Oyashio transitional waters than in the Kuroshio waters. The
estimated production of 40-mm preschooling juveniles was a positive function of larval production in the hatching length class
(5.9–9.9 mm) in the Kuroshio waters. In the Kuroshio-Oyashio transitional waters, rather than larval production in the hatching
length class, cumulative survival through the larval and early juvenile stages determined the juvenile production. Variable
growth and survival rates of saury observed in the transitional waters seem to be associated with large environmental variability
in the waters, including shifts of the Kuroshio and Oyashio fronts and development of streamers and eddies between the fronts.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
179.
Hydrographic Structure and Transport of Intermediate Water in the Kuroshio Region off the Boso Peninsula, Japan 总被引:1,自引:1,他引:1
Kosei Komatsu Yutaka Hiroe Ichiro Yasuda Kiyoshi Kawasaki Terrence M. Joyce Frank Bahr 《Journal of Oceanography》2004,60(2):487-503
Hydrographic structure and transport of intermediate water were observed in the Kuroshio region south of Japan, focusing on
the 26.6–27.5σθ density in six cruises from May 1998 through September 2001. In the section off the Boso Peninsula where the Kuroshio exfoliates
eastward, the intermediate water was clearly clustered into three groups meridionally composed of the coastal water, the Kuroshio
water and the offshore water. Compared with the Kuroshio water characterized by warm, salty water transported by the Kuroshio,
the coastal and offshore waters significantly degenerated due to mixing with cold, fresh waters originated from the subarctic
region: the former was affected by alongshore spread of the coastal Oyashio and the latter by direct intrusion of the new
North Pacific Intermediate Water (NPIW) into the southern side of the Kuroshio current axis. Particularly the offshore water
showed higher apparent oxygen utilization (AOU) in layers deeper than 26.9σθ while it showed lower AOU in layers shallower than 26.9σθ, which indicated that colder, fresher and higher AOU water was distributed on the southeastern side of the Kuroshio in deeper
layers. In May 1998, the Oyashio-Kuroshio mixing ratio was estimated to be typically 2:8 for the offshore water on the assumption
of isopycnal mixing. Moreover, northeastward volume transport of the Kuroshio water was obtained from geostrophic velocity
fields adjusted to lowered acoustic Doppler current profiler (LADCP) data to yield 6.1 Sv at 26.6–26.9σθ and 11.8 Sv at 26.9–27.5 σθ.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
180.
Gebre Girma Gezimu Isoda Hiroshi Rahut Dil Bahadur Amekawa Yuichiro Nomura Hisako 《GeoJournal》2021,86(2):843-864
GeoJournal - This study examines the impact of gender differences on maize productivity in Dawuro Zone, southern Ethiopia. Our study addressed the limitations of the previous studies in two ways.... 相似文献