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61.
Tsugunobu Nagai Masaynki Kuwashima Makoto Kawamura Tsuyoshi Kohno 《Planetary and Space Science》1979,27(7):1035-1037
It is suggested that the drop out of the 1.2–4 MeV proton flux, observed by the geostationary satellite GMS, was due to the Earthward shift of the particle boundary in all local time. The particle boundary motions are associated with substorm activities. 相似文献
62.
TIDAL FEATURES IN THE CHINA SEAS AND THEIR ADJACENT SEA AREAS AS DERIVED FROM TOPEX/POSEIDON ALTIMETER DATA 总被引:2,自引:0,他引:2
Some important tidal features of 8 major tidal constituents (M2, S2, K1, O1, P1,Sa, N2 and K2 ) in the china Seas and their adjacent sea areas were obtained using six years‘ TOPEX/POSEIDON altimeter data. The results showed that the obtained co-tidal and co-range charts for these major tidal constituents agreed well with those of previous researches using observational data from coastal tidal gauge stations and numerical models. 相似文献
63.
Water-Soluble dicarboxylic acids, ketoacids and dicarbonyls in the atmospheric aerosols over the southern ocean and western pacific ocean 总被引:2,自引:0,他引:2
Water-soluble dicarboxylic acids (DCAs), ketoacids, and α-dicarbonyls in the marine aerosol samples collected over the Southern
Ocean and western Pacific Ocean were determined. Oxalic acid was the most abundant species, followed by malonic acid and then
succinic acid. It is suggested that aerosol concentrations of the organics over the Southern Ocean in this work represent
their global background levels. Over the Southern Ocean, total concentrations of DCAs ranged from 2.9 to 7.2 ng m−3 (average: 4.5 ng m−3), ketoacids from 0.14 to 0.40 ng m−3 (av.: 0.28 ng m−3), and dicarbonyls from 0.06 to 0.29 ng m−3 (av.: 0.11 ng m−3). Over the western Pacific, total concentrations of DCAs ranged from 1.7 to 170 ng m−3 (av.: 60 ng m−3), ketoacids from 0.08 to 5.3 ng m−3 (av.: 1.8 ng m−3), and dicarbonyls from 0.03 to 4.6 ng m−3 (av.: 0.95 ng m−3). DCAs over the western Pacific have constituted a large fraction of organic aerosols with a mean DCAs-C/TC (total carbon)
of 7.0% (range: 0.59–14%). Such a high value was in contrast to the low DCAs-C/TC (av.: 1.8%; range: 0.89–4.0%) for the Southern
Ocean aerosols. Based on the relative abundances and latitudinal distributions of these organics, we propose that long-range
atmospheric transport is more important over the western Pacific Ocean, in contrast, in situ photochemical production is more significant over the Southern Ocean although absolute concentrations of the organics are
much lower. 相似文献
64.
Monthly wavenumber spectra of sea surface temperatures (SST) have been estimated in two regions near the Kuroshio, in the
recirculation and the Kuroshio Extension regions, using the merged SST product to determine the statistical parameter (spatial
decorrelation scale) required for optimal interpolation of a high-resolution SST dataset. The two-dimensional wavelet transform
was used for analysis. Estimates were made of daily mean and daily minimum SSTs. These do not significantly differ, which
suggests that the same covariance matrix can be used for the daily mean and minimum in the merging procedure. The seasonality
of wavenumber spectra is significant. There are also large differences between those in the recirculation region and in the
Kuroshio Extension region. Therefore, it is recommended that the covariance matrix in the merging process for high-resolution
SST dataset be defined as a function of time and space. Improvements of the merging methodology are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
65.
We present a case study of low-level wind jets induced in sequence by orographic effects off the Pacific coast of northern
Japan during 7–11 June 2003, and demonstrate that the transition of the wind jets causes areal differences of wave height
variations along the coast. First, we describe evolution and structure of the wind jet by analyzing SeaWinds scatterometer
wind measurements. Under the easterly wind, a strong wind jet formed after passing by Cape Erimo. As the wind shifted to the
southeast, the wind jet started to decay. In turn, the southerly wind along the coast led to another wind jet in the lee of
the easternmost tip of the Sanriku coast. We then identify onsets and decays of the wind jets from time series of wind speed
at meteorological stations. Finally, we demonstrate that the transition of the wind jets has local impacts on wave height
variations. Significant wave heights measured by altimeters were correlated positively with local wind energy, i.e., squares
of wind speeds. Accompanying the wind jet formation/decline, significant differences of wave height variations became marked
among wave observation stations located along the coast at intervals of up to 50 km. 相似文献
66.
Long-chain fatty acids (C10-C32), as well as C14-C21 isoprenoid acids (except for C18), have been identified in anhydrous and hydrous pyrolyses products of Green River kerogen (200–400°C, 2–1000 hr). These kerogen-released fatty acids are characterized by a strong even/odd predominance (CPI: 4.8-10.2) with a maximum at C16 followed by lesser amounts of C18 and C22 acids. This distribution is different from that of unbound and bound geolipids extracted from Green River shale. The unbound fatty acids show a weak even/odd predominance (CPI: 1.64) with a maximum at C14, and bound fatty acids display an even/odd predominance (CPI: 2.8) with maxima at C18 and C30. These results suggest that fatty acids were incorporated into kerogen during sedimentation and early diagenesis and were protected from microbial and chemical changes over geological periods of time. Total quantities of fatty acids produced during heating of the kerogen ranged from 0.71 to 3.2 mg/g kerogen. Highest concentrations were obtained when kerogen was heated with water for 100 hr at 300°C. Generally, their amounts did not decrease under hydrous conditions with increase in temperature or heating time, suggesting that significant decarboxylation did not occur under the pyrolysis conditions used, although hydrocarbons were extensively generated. 相似文献
67.
Retrieval of surface wave parameters from sar images and their validation in the coastal seas around Japan 总被引:2,自引:0,他引:2
We have developed a scheme to retrieve surface wave parameters (wave height and wave propagation direction) from European
Remote-Sensing Satellite (ERS) Synthetic Aperture Radar (SAR) image mode data in coastal seas around Japanese coastlines.
SAR spectra are converted to surface wave spectra of swell-dominated or wind-wave dominated cases. The SAR spectrum and SAR-derived
wind speed are used to derive the surface wave spectrum. The wind-wave dominated case and swell-dominated case are differentiated
by a wind speed of 6 m/s, and processed in different ways because of their different degree of nonlinearity. It is indicated
that the cutoff wavelength for retrieval of the wind-wave dominated spectrum is proportional to the root of significant wave
height, which is consistent with the results of previous studies. We generated 66 match-ups using the SAR sub-images and the
in-situ surface wave parameters, which were measured by wave gauges installed in near-shore seas. Among them, there are 57
swell-dominated cases, and 9 wind-wave dominated cases. The significant wave heights derived from SAR and from in-situ observation
agree with the bias of 0.09 m, the standard deviation of 0.61 m and the correlation coefficient of 0.78. The averaged absolute
deviation of wave propagation directions is 18.4°, and the trend of the agreement does not depend on the wave height. These
results demonstrate that the SAR surface wave spectrum retrieved by the present system can be used to observe the surface
wave field in the coastal seas around Japan. 相似文献
68.
A redetermination of the isotopic abundances of atmospheric Ar 总被引:5,自引:0,他引:5
Jee-Yon Lee Kurt Marti Kenji Kawamura Hee-Soo Yoo Jin Seog Kim 《Geochimica et cosmochimica acta》2006,70(17):4507-4512
Atmospheric argon measured on a dynamically operated mass spectrometer with an ion source magnet, indicated systematically larger 40Ar/36Ar ratios compared to the generally accepted value of Nier [Nier A.O., 1950. A redetermination of the relative abundances of the isotopes of carbon, nitrogen, oxygen, argon, and potassium. Phys. Rev. 77, 789-793], 295.5 ± 0.5, which has served as the standard for all isotopic measurements in geochemistry and cosmochemistry. Gravimetrically prepared mixtures of highly enriched 36Ar and 40Ar were utilized to redetermine the isotopic abundances of atmospheric Ar, using a dynamically operated isotope ratio mass spectrometer with minor modifications and special gas handling techniques to avoid fractionation. A new ratio 40Ar/36Ar = 298.56 ± 0.31 was obtained with a precision of 0.1%, approximately 1% higher than the previously accepted value. Combined with the 38Ar/36Ar (0.1885 ± 0.0003) measured with a VG5400 noble gas mass spectrometer in static operation, the percent abundances of 36Ar, 38Ar, and 40Ar were determined to be 0.3336 ± 0.0004, 0.0629 ± 0.0001, and 99.6035 ± 0.0004, respectively. We calculate an atomic mass of Ar of 39.9478 ± 0.0002. Accurate Ar isotopic abundances are relevant in numerous applications, as the calibration of the mass spectrometer discrimination. 相似文献
69.
Algorithm and validation of sea surface temperature observation using MODIS sensors aboard terra and aqua in the western North Pacific 总被引:4,自引:0,他引:4
Kohtaro Hosoda Hiroshi Murakami Futoki Sakaida Hiroshi Kawamura 《Journal of Oceanography》2007,63(2):267-280
A regional algorithm to estimate SST fields in the western North Pacific, where small oceanographic disturbance are often
found, has been developed using Moderate Resolution Imaging Spectroradiometers (MODIS) aboard Terra and Aqua. Its associated
algorithm, which includes cloud screening and SST estimation, is based on an algorithm for the Global Imager (GLI) aboard
Advanced Earth Observing Satellite-II (ADEOS-II) and is tuned for MODIS sensors. For atmospheric correction, we compare Multi-Channel
SST (MCSST), Nonlinear SST (NLSST), Water Vapor SST (WVSST) and Quadratic SST (QDSST) techniques. For NLSST, four first-guess
SSTs are investigated, including the values for MCSST, climatology with two different spatial resolutions, and near-real-time
objective analysis. The results show that the NLSST method using high-resolution climatological SST as a first-guess has both
good quality and high efficiency. The differences of root-mean-square error (RMSE) between the NLSST models using low-resolution
climatology and those using high-resolution climatology are up to 0.25 K. RMSEs of the new algorithm are 0.70 K/0.65 K for
daytime (Aqua/Terra) and 0.65 K/0.66 K for nighttime, respectively. Diurnal warming and the stratification of the ocean surface
layer under low wind are discussed. 相似文献
70.
Sohiko Kameyama Urumu Tsunogai Fumiko Nakagawa Motoki Sasakawa Daisuke D. Komatsu Akira Ijiri Junko Yamaguchi Takeo Horiguchi Hiroshi Kawamura Aika Yamaguchi Atsushi Tsuda 《Marine Chemistry》2009,115(1-2):92-101
During the Subarctic Pacific Iron Experiment for Ecosystem Dynamics Study ΙΙ (SEEDS-II), we monitored variations in the concentrations of non-methane hydrocarbons (NMHCs), CH3Cl, N2O, and CH4 within a phytoplankton bloom. Stable isotopic compositions were also determined to evaluate the sources of the variations. Although there was little variation in either the concentrations or the stable isotopic compositions of alkenes, CH3Cl, N2O, and CH4 during the 23-day observation period, alkane concentrations increased substantially as the phytoplankton bloomed. The column-integrated quantities of alkanes increased to 3 times pre-bloom levels for C2H6, 5 times for C3H8, and 20 times for n-C4H10. The δ13C values of both C2H6 and C3H8 remained almost constant while concentrations increased, whereas that of n-C4H10 increased by about 12‰. To evaluate the sources of the alkanes produced during the bloom, we compared their δ13C values with those of alkanes produced in axenic phytoplankton cultures in our laboratory. We concluded that during the SEEDS-ΙΙ experiment the major portions of C2H6 and C3H8 were produced during the autolysis of diatoms cells, whereas n-C4H10 was produced during autolysis of other phytoplankton cells such as cryptophytes and dinoflagellates. 相似文献