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71.
The Weather Research and Forecasting model was used to test the sensitivity of Typhoon Haiyan (2013) to the use of a cumulus parameterization scheme, specifically the revised Kain–Fritsch (rKF) scheme, at high horizontal resolutions with grid spacing varying from 9 to 2 km. The rKF scheme simulated the typhoon in best agreement with the observation compared with other schemes, but some fundamental drawbacks relating the rKF scheme, e.g., neglecting the momentum adjustment and being less applicable to high-resolution modeling than multi-scaled schemes, could influence the results and were discussed. Initial results showed that the typhoon track simulations benefited little from the use of the rKF scheme or a fine resolution, partially because of the similar large-scale steering flows induced by the analyzed boundary conditions used in each simulation. The influences of using the rKF scheme on typhoon intensity, size, structure, and precipitation were dependent on the grid spacing, and the most apparent changes occurred near a grid length of 4 km. At 9–4-km grid spacings, using the rKF scheme produced typhoons much stronger with more rainfall and surface latent heat flux than did using no cumulus parameterization scheme. At 3- or 2-km grid spacing, using the rKF scheme caused little changes on typhoon intensity, and the changes in precipitation and surface latent heat flux were relatively small. These results suggested that the grid spacing of 2 km for simulations using no cumulus parameterization scheme or the grid spacing of 4 km for simulations using the rKF scheme facilitated reproducing the observed Typhoon Haiyan. 相似文献
72.
采用文献[1]所述的相对日射计,将它测量晴天连续日变化资料;用谱的统计方法,来分析研究大气边界层中端涡活动。对1980年1月14和15日天两资料,用两种取样时段(总记录时间),分别进行谱的统计分析,结论:整个白天(8小时)和2小时内确有不同频率或周期的波动,以低频部分贡献大(2/3总能量),其次高频部分一般为几分钟周期变很明显。因而作者设想把它作为研究大气边界层中湍涡活动的一种探测工具,用它能测得 相似文献
73.
李金宝 《地球科学与环境学报》1998,20(3):33
地质年代表中,从震旦纪至第三纪,各个纪之间的时间间隔并不是均匀相等的。根据天文学家观测到的银河系中心(银心)的赤道座标位置,确定出太阳系在银道面上的位置,把太阳系及地球绕银河系中心公转一周的时间确定为二亿二千万年。以目前太阳系在银道面上的位置为起点,按照时间倒退,顺时针逆转做图,确定过去不同地质年代太阳系在银道面上的位置。可以发现白垩、石炭、寒武、早震旦这四个纪,第三、二叠、奥陶这三个纪,三叠、志留、晚震旦这三个纪,侏罗、泥盆这二个纪各分别发生在银道面的同一位置。 相似文献
74.
In considering the vertical heat transport problems in the upper ocean, the flat upper boundary approximation for the free
surface and the horizontal homogenous hypothesis are usually applied. However, due to the existence of the wave motion, the
application of this approximation may result in some errors to the solar irradiation since it decays quickly in respect to
the actual thickness of the water layer below the surface; on the other hand, due to the fluctuation of the water layer depth,
it is improper to neglect the effects of the horizontal advection and turbulent diffusion since they also contribute to the
vertical heat transport. A new model is constructed in this study to reflect these effects. The corresponding numerical simulations
show that the wave motion may remarkably accelerate the vertical heat transferring process and the variation of the temperature
in the wave affected layer appears in an oscillating manner.
Supported by the National High Technology Research and Development Program of China (863 Program, No. 2006AA09A309); China
Postdoctoral Science Foundation (No. 20070411111) and the Fund of Shandong Province for the Excellent Post-Doctors (No. 200603056) 相似文献
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The observation data for 5 d at a station in the South China Sea is presented.After brief analysis of the wind speed,air temperature from the ship-borne meteorological instruments and temperature and salinity profiles from the CTD (conductivity,temperature,depth recorder) data,the authors find that the CTD casts are too sparse for us to understand the diurnal evolution of the thermal structure in the upper ocean.A one-dimensional (1D) numerical code based on Mellor-Yamada turbulence closure model is used to reconstruct the upper ocean thermal structure,utilizing the atmospheric forcing data from ship-borne weather station.The simulation results show good agreement with the observational data;the significance of breaking waves is also briefly discussed.The evolution of turbulence kinetic energy (TKE) and the contribution from shear production and buoyancy production are discussed respectively.Finally,several possible factors which might influence the numerical results are briefly analyzed. 相似文献
78.
北黄海獐子岛邻近海域大型底栖动物群落结构和季节变化 总被引:1,自引:0,他引:1
本文以2009年8月-2010年6月在北黄海獐子岛海域4个季度航次调查的大型底栖动物资料为基础,分析了该海域大型底栖动物群落的结构和季节变化。结果表明,4个航次共采集了211种底栖动物,调查海域主要优势种为薄索足蛤(Thyasira tokunagai)、斑角吻沙蚕(Goniada maculata)、紫蛇尾(Ophiopholis mirabilis)、博氏双眼钩虾(Ampelisca bocki)和短角双眼钩虾(Ampelisca brevicornis),各季节的优势种组成有明显变化;运用聚类分析和MDS研究了其群落结构,将该区域大型底栖动物分为3个群落,即,群落I--位于调查区北部的美原双眼钩虾(Ampelisca miharaensis)-短角双眼钩虾(Ampelisca brevicornis)-斑角吻沙蚕群落,群落II--位于獐子岛邻近的紫蛇尾(Ophiopholis mirabilis)-日本倍棘蛇尾群落(Amphioplus japonicus),群落III--位于南部区域的薄索足蛤-浅水萨氏真蛇尾(Ophiura sarsii vadicola)群落,各群落有一定的季节变化;运用ABC曲线分析了4个季节群落受扰动情况,表明该海域环境良好,受扰动较小,夏季受扰动略大于其它季节。 相似文献
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80.
Ocean Dynamics - Sea surface temperature (SST) cooling is a typical ocean response to tropical cyclones (TCs). Previous studies have shown that TC-induced SST cooling is influenced by the TC... 相似文献