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91.
AbstractThis study modified the BTOPMC (Block-wise TOPMODEL with the Muskingum-Cunge routing method) distributed hydrological model to make it applicable to semi-arid regions by introducing an adjustment coefficient for infiltration capacity of the soil surface, and then applied it to two catchments above the dams in the Karun River basin, located in semi-arid mountain ranges in Iran. The application results indicated that the introduced modification improved the model performance for simulating flood peaks generated by infiltration excess overland runoff at a daily time scale. The modified BTOPMC was found to fulfil the need to reproduce important signatures of basin hydrology for water resource development, such as annual runoff, seasonal runoff, low flows and flood flows. However, it was also very clear that effective model use was significantly constrained by the scarcity of ground-gauged precipitation data. Considerable efforts to improve the precipitation data acquisition should precede water resource development planning.Editor D. Koutsoyiannis 相似文献
92.
Similarity solution for unsteady accretion flow is obtained. The density distribution of the initial state of the gas surrounding the star is given as ?0 ∝r ?ω. The flow patterns are compared with the results of the numerical computation by Zel'dovichet al. (1972), and it is shown that the similarity solution reproduces the results of the numerical computations well. An unsteady accretion model for the nova-like X-ray source is discussed briefly. 相似文献
93.
We present a model of solar flares triggered by collisions between current loops and plasmoids. We investigate a collision process between a force-free current loop and a plasmoid, by using 3-D resistive MHD code. It is shown that a current system can be induced in the front of a plasmoid, when it approaches a force-free current loop. This secondary current produced in the front of the plasmoid separates from the plasmoid and coalesces to the force-free current loop associated with the magnetic reconnection. The core of the plasmoid stays outside the reconnection region, maintaining high density. The core can be confined by the current system produced around the plasmoid. This collison process between a current loop and a plasmoid may explain the triggering of solar flares observed byYohkoh. 相似文献
94.
Keiichi Tadokoro Kin'Ya Nishigami Masataka Ando Naoshi Hirata Takashi Iidaka Yukihiro Hashida Kunihiko Shimazaki Shiro Ohmi Yasuyuki Kano Makoto Koizumi Shigemitsu Matsuo Hiroo Wada 《Island Arc》2001,10(3-4):235-243
Abstract A water injection experiment was carried out by the scientific drilling program named the 'Nojima Fault Zone Probe' during the two periods 9–13 February and 16–25 March 1997. The pumping pressure at the surface was approximately 4 MPa. The total amount of injected water was 258 m3 . The injection was made between depths of 1480 m and 1670 m in the Disaster Prevention Research Institute, Kyoto University (DPRI) 1800 m borehole drilled into the Nojima Fault zone. A seismic observation network was deployed to monitor seismic activity related to the water injections. Seismicity suddenly increased in the region not far from the injection hole 4 or 5 days after the beginning of each water injection. These earthquakes were likely to be induced by the water injections. Most of the earthquakes had magnitudes ranging from −2 to +1. Numerous earthquakes occurred during the first injection, but only one could be reliably located and it was approximately 2 km north of the injection site. Between the two injection periods, earthquakes concentrated in the region approximately 1 km northwest of the injection site. During and after the second injection experiment, earthquakes were located approximately 1.5 km west of the injection site. Those earthquakes were located approximately 3 km or 4 km from the injection point and between 2 km and 4 km in depth. Values of intrinsic permeability of 10−14 –10−15 m2 were estimated from the time lapse of the induced seismic activity. The coefficient of friction in the area where the induced earthquakes occurred was estimated to be less than 0.3. 相似文献
95.
Rasoul B. Sorkhabi Arvind K. Jain Tetsumaru Itaya Shiro Fukui Nand Lal Ashok Kumar 《Journal of Earth System Science》1997,106(3):169-179
The cooling and tectonic history of the Higher Himalayan Crystallines (HHC) in southwest Zanskar (along the Kishtwar-Padam
traverse) is constrained by K-Ar biotite and fission-track (FT) apatite and zircon ages. A total of nine biotite samples yields
ages in the range of 14–24 Ma, indicating the post-metamorphic cooling of these rocks through ∼ 300°C in the Miocene. Overall,
the ages become younger away from the Zanskar Shear Zone (ZSZ), which marks the basement-cover detachment fault between the
HHC and the Tethyan sedimentary zone, towards the core of the HHC. The same pattern is also observed for the FT apatite ages,
which record the cooling of the rocks through ∼ 120°C. The apatite ages range from 11 Ma in the vicinity of the ZSZ to 4 Ma
at the granitic core of the HHC. This pattern of discordant cooling ages across the HHC in southwest Zanskar reveals an inversion
of isotherms due to fast uplift-denudation (hence cooling) of the HHC core, which is, in turn, related to domal uplift within
the HHC. The Chisoti granite gneiss is the exposed domal structure along the studied traverse. Cooling history of two granite
gneisses at the core of the HHC is also quantified with the help of the biotite, zircon and apatite ages; the time-temperatures
thus obtained indicate a rapid pulse of cooling at ∼ 6 Ma, related to accelerated uplift-denudation of the HHC core at this
time. Long-term denudation rates of 0.5–0.7 mm/yr are estimated for the high-grade rocks of the Higher Himalaya in southwest
Zanskar over the past 4.0–5.5 m.yr. 相似文献
96.
97.
Noboru IMAI Shigeru TERASHIMA Shiro ITOH Atsushi ANDO 《Geostandards and Geoanalytical Research》1996,20(2):165-216
Analytical data compiled on nine Geological Survey of Japan (GSJ) reference samples, "Sedimentary rock series" received by February 1996 are reported. After excluding outliers and examining critically the analytical procedures employed, the data were evaluated statistically. Recommended or preferable values for fifteen major and sixty minor and trace elements are proposed. 相似文献
98.
Eddy activities of the surface layer in the western North Pacific detected by satellite altimeter and radiometer 总被引:5,自引:0,他引:5
Geosat radar altimeter data during the first year (from November 1986 to November 1987) of its Exact Repeat Mission are analyzed to estimate the eddy kinetic energy and propagation characteristics of anomalies of sea surface dynamic topography (SSDT) for the western North Pacific. SSDT anomalies are compared with anomalies of sea surface temperature (SST) derived from NOAA satellite radiometer data. The eddy kinetic energy (K
e
) is large in the Kuroshio stationary meander region and Kuroshio Extension region. In the downstream region of the Kuroshio Extension,K
e
is especially large on the upstream and downstream sides of prominent bathymetric features. In the interior region of the subtropical gyre is found a zonal tongue of largeK
e
at around 20–20°N. Westward propagation is dominant in the SSDT and SST anomaly field at mid-latitudes. Longitude-time lag correlation diagrams reveal the coincidence of SSDT and SST anomalies statistically, which fact suggests the baroclinic nature of the anomalies. Zonal phase speeds of SSDT anomalies are approximately equal to the theoretical speeds of baroclinic first-mode long Rossby waves, but the meridional variation of observed phase speeds does not follow the simple theoretical variation of decreasing speeds monotonously with increasing latitudes. 相似文献
99.
An image analyzing system was developed for automated identification and cell counting of a red tide phytoplankton,Prorocentrum triestinum, in coastal areas. Using an interference filter, a photograph of phytoplankton was taken through a fluorescence microscope.
The photograph was then fed into an image analyzing system consisting of an image sensor, a front mini-computer, and a host
computer. The system identifiedP. triestinum as effectively as the conventional method in one twentieth of the time required by the latter. The system was used to examine
preserved samples collected fromP. triestinum-dominated red tides in Tokyo Bay. It was found that there were two phytoplankton populations in the red tide:P. triestinum and a smaller phytoplankton. 相似文献
100.
The interaction of chromium (III) with humic substances obtained from pond sediment was experimentally studied using electrophoresis combined with ultrafiltration. The results show that within the neutral pH range chromium (III) in the presence of humic substances and some organic acids forms uncharged and/or negatively charged organic complexes of various molecular weights. A part of the chromium(III)-humic or -fulvic acid complexes having a negative charge was of lower molecular weight. Chromium (III) spiked in fresh water exists as various soluble anionic and/or uncharged species, and the molecular weights of these anionic complexes correspond to those of chromium(III)-humic and -fulvic complexes. These complexes may remain as stable dissolved forms for 10 days. The significance of the occurrence of chromium(III)-organic complexes in natural water in the geochemical cycle of chromium in the hydrosphere is discussed. 相似文献