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991.
本文根据“七五”期间建立区域地震无线数据通信网的成功经验,提出建立全国地震无线短波计算机通信网的技术方案。文中对通信网系统总体结构和组网方式、通信规程、系统功能和特点进行了介绍,重点阐述了通信网软件的设计方法和主要实现技术。 相似文献
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列举11个大地震震例研究了发震断层面剪切运动方向与地震活动特征的相关性,提出由震后地震活动条带判断发震断层面走向的方法,结果表明,动态法判定的发震断层面与其它方法判定的发震断层面非常一致。探讨了动态应力场范围、传播和对基本应力场的加强作用,以及动态应力场展布范围与大面积宏观前兆等问题。 相似文献
993.
观测断层气体的动态,研究它的异常变化与地震的相关性,是一种新的短临预报方法。1990年青海茫崖6.7级地震、共和6.9级地震前,断层气Rn、Hg的异常变化特点是临震突变幅度大、异常反应范围广。 相似文献
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Dynamic penetrometers have been used for offshore oil and gas industry applications such as pipeline feasibility studies and anchoring systems, and military applications including naval mine countermeasures and terminal ballistic studies. The main challenge of using dynamic penetrometers is the interpretation of their test results in order to deduce the mechanical properties of the penetrated soil via empirical or theoretical relations. Recently, a robust numerical method based on the Arbitrary Lagrangian–Eulerian (ALE) technique has been developed for analysing dynamic penetration problems and used to investigate a smooth penetrometer free falling into a uniform layer of clayey soil. Numerical as well as experimental results indicate that the penetration characteristics, including the impact energy, total time, and total depth of penetration, depend on the mechanical properties of the soil including its stiffness and strength parameters as well as the geometry of the penetrometer and its initial impact energy. In this study, the ALE method is employed to study the effect of shear strength increasing with depth (a common condition of seabed deposits) on the penetration characteristics of a free falling penetrometer. Conducting more than two thousand numerical simulations has shown that there is an approximate quadratic relation between the final embedment depth of a FFP penetrating into a non-uniform clay soil and the combined kinetic energy on contact with the soil and subsequent loss in potential energy of the penetrometer. 相似文献
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This study proposes an improved tunnel model for evaluating train-induced dynamic stress in saturated soils, which can consider multiple moving loads, grouting layer and pore-water pressure. Using Shanghai Metro’s actual parameters for train speed, tunnel, grouting layer and soils, the analysis of the spatial distribution of dynamic stress for soils and stress state of various locations under moving train loads shows that neglecting effects such as pore-water pressure can lead to underestimating dynamic normal stress and overestimating dynamic shear stress in the soils below tunnel. This model can be further extended to investigate principal stress axes rotations and tunnel settlement. 相似文献
999.
Review of Development and Application of High Resolution Global Climate System Model 总被引:1,自引:0,他引:1
Climate models have been used as an important tool to quantitatively study climate variability and to predict or project climate change in the future. One of the most important pathways for development and improvement of climate system model is to increase the spatial resolution and improve the corresponding physical parameterization schemes, which is very important for understanding climate change and improving climate prediction skill. Based on a brief introduction of the importance of developing high-resolution global climate system model, a review of recent progresses in the development and application of high-resolution models was summarized. The paper also introduced the current situation and problems for the development and evaluation of high-resolution models and focused on the key scientific and technical bottlenecks which restrict the development of high-resolution models, including the development of dynamic framework of the high-resolution ocean and atmospheric models and massive high performance parallel computing, the improvement of the sub-grid physical parameterization scheme, and mesoscale air-sea interaction. Meanwhile, the scientific objects and experiments design of the international high resolution climate model intercomparison project (HiResMIP) of the coupled model intercomparison project phase 6 (CMIP6) was introduced. Finally, we prospect the future developments and evaluations of high-resolution climate models in China was proposed. 相似文献
1000.
The most common method of reducing roll motion of ship-shaped floating systems is the use of bilge keel which act as damping elements. The estimation of the damping introduced by bilge keel is still largely based on empirical methods. The present work adopts the CFD approach to the estimation of roll damping, both without and with bilge keel and validates the results with experiments conducted in a wave flume. Specifically, free oscillation tests are conducted at model scale to obtain roll damping, both by experiments and CFD simulation and reasonably good comparisons are obtained. The experiments also include PIV study of the flow field and attempt has been made to correlate the measured flow field with that obtained by CFD. The CFD methodology has the potential to determine rationally the size and orientation of bilge keels in design with reasonably accurate estimate of the additional roll damping that it provides to ship's roll motion. 相似文献