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91.
92.
裂隙网络多标度分形计算机模拟 总被引:1,自引:0,他引:1
岩体裂隙网络是不均匀,非对称的复杂分形,用简单分数维不能刻画其特征,必须采用多标度分形来研究,才能全面客观地描述其本质。文中介质了隙网络多标度分形计算机模拟原理与方法。 相似文献
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单图像三维立体图简介 总被引:2,自引:0,他引:2
林存山 《物探化探计算技术》1996,18(1):52-59,70
立体图指的是在观察图画中的深度时,通过双眼的配合能够构造出一幅心理上的立体透视图来。人们常规的做法是使用一对像图来获得立体景色,这样的图要经适当的制作并要用双眼分别各看一张。近年来,借助于计算机产生的随机点图可用来勾绘出实物。这种随机点图如用单只眼睛观看时则是毫无意义的,但如用双眼观看时便可产生出立体景色。原先这样的随机点立体图似乎均要求制成两张图,但最近的工作表明将此种图合二而一的方法已获成功。 相似文献
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呼叫中心在气象系统中的应用研究 总被引:2,自引:0,他引:2
从呼叫中心的产生背景入手,分析了呼叫中心在气象服务中应用的必要性,并从应用的角度对系统结构及系统功能等进行了简单的介绍。 相似文献
97.
A new measurement system for laboratory wave flumes is presented, based on the analysis of digital images by means of computer vision techniques. Unlike conventional wave gauges, the system detects the motions of the free surface along the flume section of interest as opposed to a point. A further advantage lies in that no sensors are necessary within the flume. The system is particularly useful in the case of wave flume tests of floating bodies, such as an oil boom—the motions of the model boom are measured without any sensors in contact with it, which otherwise might place constraints on its displacements. The new method is validated based on free surface measurements carried out with a conventional wave gauge, with excellent results. 相似文献
98.
浅谈计算机机房布线与防雷 总被引:3,自引:2,他引:1
文章主要讲述机房在设计和施工中需要考虑与布线的关系以及应当注意的一些事项,是作者在工程实践防雷中对机房布线和防雷工作的一些认识,仅供参考。 相似文献
99.
M.G. Berthoud 《Icarus》2005,175(2):382-389
An increasing number of objects discovered in the Solar System have irregular shapes which require unconventional mapping techniques. Here we present a technique that produces equivalent maps of such objects. As such maps preserve surface area they are especially useful for mapping the distribution of geological features on irregular objects. Maps of blocks and craters on the Asteroid 433 Eros are used to illustrate the potential use of the technique. Two equal-area maps are adequate to cover the entire asteroid and convincingly demonstrate variations in surface density of mapped features. Similar coverage by orthographic views requires 4 to 6 plots. The distortion of the maps are comparable to the distortions of maps created by other techniques. 相似文献
100.
The scattering properties of particulate rings with volume filling factors in the interval D=0.001-0.3 are studied, with photometric Monte Carlo ray tracing simulations combining the advantages of direct (photons followed from the source) and indirect methods (brightness as seen from the observing direction). Besides vertically homogeneous models, ranging from monolayers to classical many-particle thick rings, particle distributions obtained from dynamical simulations are studied, possessing a nonuniform vertical profile and a power law distribution of particle sizes. Self-gravity is not included to assure homogeneity in planar directions. Our main goal is to check whether the moderately flattened ring models predicted by dynamical simulations (with central plane D>0.1) are consistent with the basic photometric properties of Saturn's rings seen in ground-based observations, including the brightening near zero phase angle (opposition effect), and the brightening of the B-ring with increasing elevation angle (tilt effect). Our photometric simulations indicate that dense rings are typically brighter in reflected light than those with D→0, due to enhanced single scattering. For a vertically illuminated layer of identical particles this enhancement amounts at intermediate viewing elevations to roughly 1+2D. Increased single scattering is also obtained for low elevation illumination, further augmented at low phase angles α by the opposition brightening when D increases: the simulated opposition effect agrees very well with the Lumme and Bowell (1981, Astron. J. 86, 1694-1704) theoretical formula. For large α the total intensity may also decrease, due to reduced amount of multiple scattering. For the low (α=13°) and high (α=155°) phase angle geometries analyzed in Dones et al. (1993, Icarus 105, 184-215) the brightness change for D=0.1 amounts to 20% and −17%, respectively. In the case of an extended size distribution, dynamical simulations indicate that the smallest particles typically occupy a layer several times thicker than the largest particles. Even if the large particles form a dynamically dense system, a narrow opposition peak can arise due to mutual shadowing among the small particles: for example, a size distribution extending about two decades can account for the observed about 1° wide opposition peak, solely in terms of mutual shadowing. The reduced width of the opposition peak for extended size distribution is in accordance with Hapke's (1986, Icarus 67, 264-280) treatment for semi-infinite layers. Due to vertical profile and particle size distribution, the photometric behavior is sensitive to the viewing elevation: this can account for the tilt-effect of the B-ring, as dense and thus bright central parts of the ring become better visible for larger elevation, whereas in the case of smaller elevation, mainly low volume density upper layers are visible. Since multiple scattering is not involved, the explanation works also for albedo well below unity. Inclusion of nonzero volume density helps also to model some of the Voyager observations. For example, the discrepancy between predicted and observed brightness at large phase angles for much of the A-ring (Dones et al., 1993, Icarus 105, 184-215) is removed when the enhanced low α single scattering and reduced large α multiple scattering is allowed for. Also, a model with vertical thickness increasing with saturnocentric distance offers at least a qualitative explanation for the observed contrast reversal between the inner and outer A-ring in low and high phase Voyager images. Differences in local size distribution and thus on the effective D may also account for the contrast reversal in resonance sites. 相似文献