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71.
Ten new species of cyclopoid copepods are described as parasites of marine fishes from Korea. Three new species of the family Bomolochidae are described as gill parasites: Orbitacolax pteragogi n. sp. from Pteragogus flagellifer (Valenciennes), Orbitacolax trichiuri n. sp. from Trichurus lepturus Linnaeus, and Orbitacolax unguifer n. sp. from Evynnis japonica Tanaka. Four species of the genus Colobomatus Hesse, 1873 of the family Philichthyidae are described as internal parasites: Colobomatus unimanus n. sp. from Pseudolabrus eoethinus (Richardson), Colobomatus recticaudatus n. sp. from Halichoeres poecilopterus (Temminck and Schlegel), Colobomatus floridus n. sp. from Hapalogenys mucronatus (Eydoux and Souleyet), and Colobomatus orientalis n. sp. from Johnius grypotus (Richardson). Three new species of the family Taeniacanthidae, including a new species belonging to a new genus, are described as gill parasites: Taeniacanthus singularis n. sp. from Halieutaea fumosa Alcock, Triacanthus luteus n. gen. n. sp. from Odontamblyopus lacepedii (Temminck and Schlegel), and Umazuracola geminus n. sp. from Stephonolepis cirrhifer (Temminck and Schlegel).  相似文献   
72.
Eight species of the Hatschekiidae are recorded as parasites of marine fishes from southern coast of Korea. One new species, Hatschekia jejuensis, parasitic on Cheilodactylus zonatus Cuvier is included. The remaining seven species are new to Korean fauna: Hatschekia iridescens Wilson, 1913, H. japonica Jones, 1985, H. monacanthi Yamaguti, 1939, H. tenuis (Heller, 1865) H. pseudolabri Yamaguti, 1953, H. cylindrica Shiino, 1957, and Pseudocongericola chefoonensis Yü, 1933. Hatschekia jejuensis n. sp. has a combination of characteristics in the female where the trunk is 2.35 times as long as the cephalothorax and displays a pair of posterolateral bulges on both sides, the antennules is 5-segmented, the mandible bears six teeth, and the armature formulae of the legs are I-0; III (exopod) and 0-0; II (endopod) for leg 1 and I-0; I (exopod) and 0-0; II (endopod) for leg 2.  相似文献   
73.
The Yellow Sea Bottom Cold Water (YSBCW) is a large cold water mass lying in the deep part of the Yellow Sea during the warm season. We acquired multichannel seismic (MCS) data using an air gun source to image the structure of the YSBCW. The MCS data recorded reflections from sea water. The recognition of these reflections was confirmed by finite-difference seismic modeling in the frequency-domain. The seismic section from MCS data enabled discrimination of water masses distinctly separated by reflecting horizons. The structure of the water masses is fairly consistent with temperature-depth variations obtained using expandable bathythermograph (XBT) casts. The YSBCW is imaged as the lowermost water mass, maximally 40 m thick, that extends as a lens-like form along the sea bottom under the warm mixed layer. The correlation of XBT measurements and the seismic section indicates a rapid decrease in temperature from around 11 to 8 °C in the uppermost part of the YSBCW. A transition zone between the mixed layer and the underlying YSBCW is also defined. This transition zone has fairly uniform thickness of 14–18 m and marks an interval of rapid temperature drop, indicating vigorous thermal mixing. Our study demonstrates that MCS profiling is a useful and reliable tool for imaging fine structures in the shallow Yellow Sea.  相似文献   
74.
The environmental issues associated with mining have damaged the industry’s substantial global economic value. In particular, the mining industry has a negative legacy of contaminated land. The effective reclamation of contaminated soil is therefore required before former mining land can be further developed for residential and commercial purposes. The objective of this study was to technically evaluate the feasibility of reclamation techniques for agricultural soils contaminated with toxic elements (As, Cd, Cu, Pb, and Zn) associated with metal mining. The reclamation methods investigated were covering without stabilization, covering with stabilization, and exchange with stabilization. The thickness of the soil layer used in covering and exchange was in the range of 30–50 cm. Limestone, furnace slag, and a mixture of limestone and furnace slag were applied as soil amendments. After reclamation, the contamination level in surface tillage soils and crops was monitored regularly. Four years of monitoring data revealed that surface soil contamination levels could be maintained at acceptable levels, although at some sites, the metal levels in crops exceeded legislative limits. Soil reclamation at former mining sites in Korea has not yet been perfected, but the results of this study show that there is potential for safe agricultural operations on large sites in a cost-effective manner, as long as the appropriate control of surface soil contamination and adequate agronomic management is undertaken.  相似文献   
75.
This is the first study to report the concentrations and accumulation profiles of PFCs in marine mammals from Korea. The concentrations and profiles of 10 PFCs in the liver of minke whales and common dolphins from Korean coastal waters were recorded in this study. The mean concentrations of PFOS and PFUnDA were 3-20 times higher than that found for other PFCs analyzed. The concentrations of PFOS in cetaceans from Korea were relatively lower than those reported in other countries. Inter-species differences in the concentrations of PFOS, PFOSA and PFNA were found between two cetacean species, while no difference was observed in the concentrations of PFDA, PFUnDA and PFDoDA between the species. The dominant PFC compounds found in cetaceans were PFUnDA and PFOS, accounting for 70-80% of the PFCs. The accumulation profiles and correlation analysis indicated that two cetacean species have different exposure routes and metabolic capacity for PFCs.  相似文献   
76.
Diatom densities in the surface water and dinoflagellate cysts in bottom sediments of Gwangyang Bay were studied to determine changes in the phytoplankton community structure in response to anthropogenic eutrophication and to assess the use of dinoflagellate cysts as indicators of coastal eutrophication. Our results show that, in nutrient-enriched environments, diatoms are particularly benefited from the nutrients supplied and, as a consequence, heterotrophic dinoflagellates that feed on the diatoms can be more abundant than autotrophic dinoflagellates. In short-core sediment records, a marked shift in autotrophic–heterotrophic dinoflagellate cyst compositions occurred at a depth of approximately 9–10 cm corresponding to the timing of the 1970s industrialization around Gwangyang Bay. This tentatively indicates that diatom and dinoflagellate communities here have undergone a considerable change mainly due to increased nutrient loadings from both domestic sewage effluent and industrial pollution. Our study suggests a possible potential use of dinoflagellate cysts in providing retrospective information on the long-term effects of coastal eutrophication.  相似文献   
77.
This paper proposes a dynamic centrifuge model test method for the accurate simulation of the behaviours of a liquid storage tank with different types of foundations during earthquakes. The method can be used to determine the actual stress conditions of a prototype storage‐tank structure. It was used in the present study to investigate the soil‐foundation‐structure interactions of a simplified storage tank under two different earthquake motions, which were simulated using a shaking table installed in a centrifuge basket. Three different types of foundations were considered, namely, a shallow foundation, a slab on the surface of the ground connected to piles and a slab with disconnected piles. The test results were organised to compare the ground surface and foundation motions, the slab of foundation and top of structure motions and the horizontal and vertical motions of the slab, respectively. These were used to establish the complex dynamic behaviours of tank models with different foundations. The effects of soil–foundation–structure interaction with three foundation conditions and two different earthquake motions are focused and some important factors, that should be considered for future designs are also discussed in this research. Copyright © 2017 John Wiley & Sons, Ltd.  相似文献   
78.
Chae (2001) first proposed a method of self-consistently determining the rate of change of magnetic helicity using a time series of longitudinal magnetograms only, such as taken by SOHO/MDI. Assuming that magnetic fields in the photosphere are predominantly vertical, he determined the horizontal component of velocity by tracking the displacements of magnetic flux fragments using the technique of local correlation tracking (LCT). In the present paper, after briefly reviewing the recent advance in helicity rate measurement, we argue that the LCT method can be more generally applied even to regions of inclined magnetic fields. We also present some results obtained by applying the LCT method to the active region NOAA 10365 under emergence during the observable period, which are summarized as follows. (1) Strong shearing flows were found near the polarity inversion line that were very effective in helicity injection. (2) Both the magnetic flux and helicity of the active region steadily increased during the observing period, and reached 1.2 × 1022 Mx and 8 ×1042 Mx2, respectively, 4.5 days after the birth of the active region. (3) The corresponding ratio of the helicity to the square of the magnetic flux, 0.05, is roughly compatible with the values determined by other studies using linear-force-free modeling. (4) A series of flares took place while the rate of helicity injection was high. (5) The choice of a smaller window size or a shorter time interval in the LCT method resulted in a bigger value of the LCT velocity and a bigger value of the temporal fluctuation of the helicity rate. (6) Nevertheless when averaged over a time period of about one hour or longer, the average rate of helicity became about the same within about 10%, almost irrespective of the chosen window size and time interval, indicating that short-lived, fluctuating flows may be insignificant in transferring magnetic helicity. Our results suggest that the LCT method may be applied to 96-minute cadence full-disk MDI magnetograms or other data of similar kind, to provide a practically useful, if not perfect, way of monitoring the magnetic helicity content of active regions as a function of time.  相似文献   
79.
80.
It has been shown by the observed data that during the early 1990’s, the severe disastrous climate occurred in East Asia. In the summer of 1991, severe flood occurred in the Yangtze River and the Huaihe River basin of China and in South Korea, and it also appeared in South Korea in the summer of 1993. However, in the summer of 1994, a dry and hot summer was caused in the Huaihe River basin of China and in R. O. K.. In order to investigate the seasonal predictability of the summer droughts and floods during the early l990’s in East Asia, the seasonal prediction experiments of the summer droughts and floods in the summers of 1991-1994 in East Asia have been made by using the Institute of Atmospheric Physics-Two-Level General Circulation Model (IAP-L2 AGCM), the IAP-Atmosphere/Ocean Coupled Model (IAP-CGCM) and the IAP-L2 AGCM in?cluding a filtering scheme, respectively. Compared with the observational facts, it is shown that the IAP-L2 AGCM or IAP-CGCM has some predictability for the summer droughts and floods during the early 1990’s in East Asia, es?pecially for the severe droughts and floods in China and R. O, K.. In this study, a filtering scheme is used to improve the seasonal prediction experiments of the summer droughts and floods during the early 1990’s in East Asia. The predicted results show that the filtering scheme to remain the planetary-scale disturbances is an effective method for the improvement of the seasonal prediction of the summer droughts and floods in East Asia.  相似文献   
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