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341.
Michio J. Kishi Hitoshi Motono Makoto Kashiwai Atsushi Tsuda 《Journal of Oceanography》2001,57(5):499-507
A vertical one-dimensional ecosystem model with vertical migration of zooplankton was constructed and applied to Station A-7
off Sanriku district of Japan in the northwest Pacific Ocean. The model consists of an eight-compartment ecosystem model coupled
with a physical model of the oceanic mixed layer. The transition of phytoplankton species responsible for the spring bloom
is well reproduced by this model with vertical migration of zooplankton but is not simulated by the model without vertical
migration. This new model also simulates an observed inter-annual variability of the spring bloom, with the timing and intensity
of the simulated bloom in a given year depending upon the strength of mixing during the preceding winter.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
342.
Some temperature profiles observed in sea floor sediments of the Japan Sea, west of the northern part of Honshu, show distinct gradients changing with depth, for which we use the term warping. Using a simplified model, this warping can be attributed to an abrupt temperature change in the bottom water just above the sediment. The bottom water temperature change might be explained by the hypothesis that warm and salt surface water in the region sank to the sea bottom, through colder and less saline water, maintaining a relatively warmer temperature than the bottom water which originates from ordinary lateral intrusion. 相似文献
343.
Motohiko Kashima Shiro Imawaki Shin-Ichiro Umatani Hiroshi Uchida Yuji Hashibe Hiroshi Ichikawa Masao Fukasawa 《Journal of Oceanography》2003,59(3):291-301
Theoretically, the geostrophic approximation holds for the low-frequency flow field, but no detailed examination has been
done on how well the estimated geostrophic velocity corresponds with the observed velocity. Intensive surveys were carried
out during 1993–1995 in the Kuroshio and its recirculation regions south of Shikoku, Japan, including repeated hydrographic
surveys and direct current measurements at nominal depths of 700, 1500 and 3000 m. For these depth intervals, vertical differences
of estimated geostrophic velocity are compared with those of observed velocity. For the intermediate layer (between 700 and
1500 m depths), the slope of the regression line is 0.99, correlation coefficient is 0.98, and the root-mean-square of difference
from geostrophic balance is 2.8 cm/s which is close to the estimated error of 2.1 cm/s. For the deep layer (between 1500 and
3000 m depths), the corresponding values are 0.82, 0.93, 1.2 cm/s and 2.0 cm/s, respectively. The results indicate that the
estimated geostrophic velocity compares well with the observed velocity in these regions.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
344.
利用流水饲养法研究了不同浓度的三丁基氧化锡 (0 .5 μg/ L和 1.0 μg/ L TBTO)对太平洋牡蛎卵巢中卵母细胞直径、RNA/ DNA比、蛋白质和卵黄蛋白含量的影响。卵母细胞径的增长在0 .5 μg/ L实验组受到阻碍 ,并随着 TBTO浓度的增大而更加明显。TBTO暴露组的 RNA/ DNA比在精巢中无明显变化 ,但在卵巢中显著低于对照组。 TBTO暴露组的卵巢中蛋白质和卵黄蛋白含量显示了与 RNA/ DNA比相同的变化趋势 ,表明 TBTO的积累阻碍卵黄蛋白的合成。TBTO暴露4 2 d采集的牡蛎样品中出现 3个雌雄同体 ,暗示 TBTO可能引起牡蛎发生性转变进而产生雌雄同体 相似文献
345.
Akihiko Kuwahara Tsuneyuki Abe Masayuki Shimono Makoto Kashiwai Masatosi Sinoda 《Journal of Oceanography》1973,29(3):106-112
A pump-sampler was designed to study the distribution of marine plankton and its possible relationship with the temperature and salinity of the water. Sea water was pumped up through a 2 inch diameter hose and plankton contained in it was collected on a filter cup (2 inches in diameter, 139 meshes/inch) without being damaged. The filter cup, when clogged by plankton organisms, was washed by spraying with about 100 cu. cm of water. The differences between two continuous with an interval of more than 3–4 seconds could be detected.A preliminary operation along a 2.82 km course in Maizuru Bay was carried out simultaneously with temperature-salinity measurements at sampling intervals of 30 m. Temperature was measured by a thermistor resistance thermometer, and salinity was measured by a salinometer with a subsample of water which was collected from an additional opening of the pump-sampler. The temperature-salinity record showed that four zones of water were characterized.It was found that wide variation of plankton counts indicated dense concentrations of particular species or group of species, and on the mesoscale it was possible to examine the size of the aggregation. 相似文献
346.
Two recent records of the occurrences of the pelagic shrimp,Sergestes similis Hansen, are reported. They provide evidence of dense swarms ofS. similis in midwater off the east coast of Honshu, Japan, in spring. On one occasion,S. similis was found in a stomach of the basking shark,Cetorhinus maximus (Gunnerus). The shark, 8.11 m in total length, was accidentally trapped in a set net off Izu-oshima Island on April 18, 1974, and its foregut was filled only withS. similis. Feeding and swimming behavior of the basking shark, condition of the gut contents, and temperature profiles of the sea revealed thatS. similis was preyed upon by the shark near the island when the shrimp swarmed below 100 m depth at night. On another occasion,S. similis was fished by a commercial ground trawler 31 miles off Cape Shioyazaki on April 4 and 5 and off Hitachi on April 11, 1976. The trawlings were made around 500 m depth at daytime, and a total of 3.8 tons ofS. similis was caught and marketed. The size-frequency distribution and sex ratio ofS. similis in both occurrences from off Izu-oshima Island and off Cape Shioyazaki coincided very well. The samples consisted of identical population of probably 2nd year class having a body length mode between 46.0 and 50.0 mm. The sex ratio was skewed greatly toward females in both samples, that is 38∶2 and 100∶3 respectively. These two phenomena are discussed in relation to the life history ofS. similis. 相似文献
347.
Tatsuki Toda Tomoko Okashita Takeshi Maekawa Bin Abdul Adzis Kee Alfian Mohd Kushairi Mohd Rajuddin Ryota Nakajima Wenxi Chen Kunio T. Takahashi Bin Haji Ross Othman Makoto Terazaki 《Journal of Oceanography》2007,63(1):113-123
Coral community structures at eleven fringing reef sites were investigated along the coast of Peninsular Malaysia. Estimated
coverage of coral communities is examined by applying quantitative digital image analysis to the line transect method. Four
coral community types were characterized by dominant genera and lifeforms: Acropora branching community, Montipora-Acropora community, Porites massive community, and Heliopora community. Live coral coverage in all study sites ranged from 17.9% to 68.6%. Most reefs were in “fair” condition while some
reefs were shown to be in “poor” condition. Coral community structures among the study sites were divided into the west coast
of Peninsular Malaysia with a dominant Porites massive lifeform, and the east coast with a variety of lifeform categories of Montipora and Acropora. Physical effects such as the monsoon wind regime and sedimentation are likely to influence the formation of dominant coral
communities around Peninsular Malaysia. 相似文献
348.
Masashi Taguchi Kenji Yasuda Shozo Toda Makoto Shimizu 《Marine environmental research》1979,2(3):239-249
Concentrations of Hg, Zn, Fe, Cd and Cu in the muscle tissues of a dogfish, Squalus mitsukurii, were determined by atomic absorption spectrometry and found to be in the ranges of f0·019–2·13, 1·8–3·6, 1·5–5·7, 0·001–0·018 and 0·12–0·70 μg/g wet weight, respectively. The frequency distributions of concentrations, with the exception of mercury, were found to be log-normal. The correlation coefficient between mercury content and total length was positive and large and statistically highly significant. For other metals negative correlations were observed. Mercury concentration in the muscle was found to increase in proportion to the total length cubed. Regression of mercury concentration on age of sharks was shown to be linear. Analysis of covariance showed that the difference between sexes was not statistically significant, either in slope or in height. The concentration of mercury in the muscle tissues of embryos was considerably lower, Cd roughly the same and Zn and Fe higher than those of mothers. The concentrations of Zn, Fe and Cu are higher in the embryonic stage and immediately after birth than in later stages of growth. 相似文献
349.
Tsutomu Sato Isao Machida Makoto Takahashi Taro Nakamura 《Pure and Applied Geophysics》2006,163(4):809-823
Water was sampled from eight springs and a lake in volcanic Miyakejima Island of Japan after the 2000 eruption. Major chemical
and isotopic compositions of the water were analyzed. Significant increases of sulfate ion are observed in several springs
where the thickness of ejecta exceeds 32 mm. A good relationship of Cl/S mole ratios between spring water and leachate of
the ejecta is observed. Sulfur isotopic compositions of the spring water become close to that of leachate of the ejecta as
time elapses after the eruption. Consequently the sources of the added sulfate ion in the spring water after the eruption
are interpreted to be anhydrite and adhered sulfur of the ejecta. 相似文献
350.
Peng Pan Hiroshi Tomofuji Tao Wang Masayoshi Nakashima Makoto Ohsaki Khalid M. Mosalam 《地震工程与结构动力学》2006,35(7):867-890
A new Internet online hybrid test system, designated the ‘peer‐to‐peer (P2P) Internet online hybrid test system’, is proposed. In the system, the simulated structure is divided into multiple substructures, and each substructure is analysed numerically or tested physically in parallel at geographically distributed locations. The equations of motion are not formulated for the entire structure but for each substructure separately. Substructures are treated as highly independent systems, and only standard I/O, i.e. displacements and forces at the boundaries, are used as interfaces. A ‘Coordinator’ equipped with an iterative algorithm based on quasi‐Newton iterations is developed to achieve compatibility and equilibrium at boundaries. A test procedure, featuring two rounds of quasi‐Newton iterations and using assumed elastic stiffness, is adopted to avoid iteration for the substructure being tested physically. A fast and stable solution using a socket mechanism is developed for data exchange over the Internet. Demonstration tests applied to a base‐isolated structure was conducted, and the results are compared with an online hybrid test using the conventional test method. The results obtained from the P2P Internet hybrid test match very closely those obtained from the conventional tests. Investigations are also carried out on time consumption and control accuracy. The results show that the Internet data exchange solution using the socket mechanism is fast, and tests were completed successfully under the constructed Internet online hybrid test environment. Copyright © 2006 John Wiley & Sons, Ltd. 相似文献