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141.
Ma Mintao Guan Guangyue Department of Chemistry Environment Engineering Beijing Polytechnic University Beijing Geological Department Northeast University of Technology Shenyang Liaoning Fei Zhenbi 《《地质学报》英文版》1997,71(1):58-68
The Sain Us gold deposit is a typical auriferous sulphide quartz vein deposit in the InnerMongolian arid steppe climatic region. The oxidation zone has been controlled by the arid cli-mate since the beginning of the Holocene. Gold supergene evolution is characterized by enlarge-ment of gold grains, complication of the gold form, raising of the gold grade and increase of thegold fineness; besides, gold and silver have two enrichment peaks at the same depth, which is insharp contrast to the unimodal enrichment of gold and silver and the occurrence of gold aboveand silver below in a humid climatic region. Sun pumping is the main cause for the bimodalenrichment of gold and silver. Illite 2 M_1 is one of the main causes for the upper enrichment peakof gold and silver. 相似文献
142.
介绍了一种新的建立太阳辐射压摄动模型的方法,即Vokrouhlicky等人提出的方法。该方法以辐射转移方程为基本数学工具,并运用相应的物理概念,通过对太阳辐射场强和辐射流量的计算来求出太阳辐射压摄动。此方法既适用于卫星处于地球半影区内和地球阴影之外的情形,也适用于地球反照辐射压的计算。还介绍了该方法的一些计算结果,并简单评述了其不足之处。 相似文献
143.
利用卫星遥感影像中朵云与其阴影的成像差异以及扫描区域与成像时刻太阳方位角的关系,建立了3种云朵高度的计算公式.在此基础上,进一步提出了概略计算扫描区域坐标的方法.实验结果表明,该方法有效地解决了在缺乏传感器摆角的情况下对扫描区域的概略定位问题.根据推导的公式,利用物体与阴影在太阳赤纬角上的分量,还可以解决摄影时间不精确情况下的物体高度计算.该方式比用太阳高度角在时间上的敏感程度要小,因而降低了对时间的要求,尤其对单片航空摄影测量中物体高度计算更有利. 相似文献
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海面发生大面积溢油事故时,由于太阳耀斑区的存在,海面的油膜在遥感影像上会发生明暗的变化。这对溢油的检测会产生严重的干扰。如何在海面太阳耀斑区准确地检测出溢油是目前溢油检测的难题。针对这一问题,本文利用Landsat7 ETM+多光谱影像数据,开展了基于卷积神经网络(CNN)的海面太阳耀斑区溢油检测方法研究。通过设置对照实验,对比支持向量机、最大似然、随机森林等分类方法,我们发现在相同实验条件下CNN模型的分类精度为95%~99%, Kappa系数为0.92~1,均高于其他三种分类方法,表明了CNN模型在海面太阳耀斑区溢油的检测具有更高的精度与一致性。 相似文献
147.
Kang Kai-Feng Yan Xiao-li Xu Zhi Wu Ning Lin Jun 《Chinese Astronomy and Astrophysics》2018,42(3):386-420
Quasi-separatrix layer, also called as QSL, is a region where magnetic connectivity changes drastically, and mostly well coincides with the location of flare ribbons in observations. The research on the relations of this topological structure with the 3-dimensional magnetic reconnection, and solar flares has attracted more and more attention. In this paper, using the theory of QSL we investigate a C5.7 classical two-ribbon solar flare (event 1) which occurred at AR11384 on 2011 December 26, and an M6.5 solar flare (event 2) which occurred at AR12371 on 2015 June 22, respectively. Combining the multi-wavelength data of AIA (Atmospheric Imaging Assembly) and vector magnetogrames of HMI (Helioseismic and Magnetic Imager) onboard SDO (Solar Dynamics Observatory), we extrapolate the coronal magnetic field using the PF (Potential Field) and NLFFF (Nonlinear Force Free Field) models, and calculate the evolution of the AR (Active Region) magnetic free energy. Then, we calculate the logarithmic distribution of Q-factors (magnetic squashing factor) at different heights above the solar photosphere with the results of the PF and NLFFF extrapolations, in order to determine the location of QSL. Afterward, we investigate the evolutionary relation between the QSLs at different heights above the solar photosphere and the flare ribbons observed at the corresponding heights. Finally, we study the multi-wavelength evolution features of the 2 flare events, and obtain by calculation the mean slip velocities of magnetic lines in the event 2 at 304 Å and 335 Å to be 4.6 km s-1 and 6.3 km s-1, respectively. We find that the calculated location of QSL in the chromosphere and corona is in good agreement with the location of flare ribbons at the same height, and the QSLs at different heights have almost the same evolutionary behavior in time as the flare ribbons of the corresponding heights, which highlights the role of QSL in the research of 3D magnetic reconnection and solar flare, and we suggest that the energy release in the flare of event 2 may be triggered by the magnetic reconnection at the place of QSL. We also suggest that the QSL is very important for us to study the essential relation between the 3D and 2D magnetic reconnections. 相似文献
148.
Observations indicated that solar coronal mass ejections (CMEs) are closely asociated with reconnection-favored new flux emergence. By means of numerial simulations, a physical model of the emerging flux trigger mechanism for CMEs is proposed and explained well the observational results. Based upon this model, leaving the gravity and heat conduction out of consideration, the theoretical results of 2.5 dimensional numerical simulations indicate that whether a CME can be triggered depends on both the amount and the location of an emerging flux, besides its polarity orientation. Furthermore, the eruption and non-eruption regimes are presented in parameter space. By use of 15 filament eruption events in 2002 and 2003 and 44 non-eruption events in 2002, the results of a statistical study on the properties of emerging flux including its polarity orientation, its location and the amount of flux show that not all the emerging flux can make a filament to lose equilibrium and trigger the onset of a CME, The statistic results basically support the theoretical results of numerical simulations. This research provides useful information for the space weather forecast. 相似文献
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It is a common practice in the solar physics community to judge whether the measured photospheric vector magnetograms are force-free or not. In the previous work, it was studied how the measurement limitations such as the limited field of view, instrument sensitivity, and measurement error could affect the judgement of force-freeness based on the observed magnetograms. A further research on the influence of the spatial resolution on the force-freeness judgement is carried out in this article. The result shows that changing (mainly reducing) the spatial resolution has little influence on the force-freeness judgement in the ideal noiseless case. In the case when there are white noises in the magnetograms as those in the really observed magnetograms, it is opposite to the common intuition that properly reducing the spatial resolution can actually suppress the error, and significantly reduce the heavy influence of the measurement error on the force-freeness judgement, thus to enhance effectively the accuracy of the force-freeness judgement of magnetic field. This result sets up a theoretical foundation and an instructive guidance for judging the force-freeness of solar magnetic field correctly by using the observed magnetograms. 相似文献