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801.
Yin‐Nan Huang Andrew S. Whittaker Michael C. Constantinou Sanjeev Malushte 《地震工程与结构动力学》2007,36(12):1741-1761
Numerical models of a sample nuclear power plant (NPP) reactor building, both conventionally constructed and equipped with seismic protective systems, are analysed for both safe shutdown and beyond‐design‐basis earthquake shaking at two coastal sites in the United States. Seismic demands on secondary systems are established for the conventional and seismically isolated NPPs. The reductions in secondary‐system acceleration and deformation demands afforded by the isolation systems are identified. Performance spaces are introduced as an alternate method for evaluating demands on secondary systems. The results show that isolation systems greatly reduce both the median and dispersion of seismic demands on secondary systems in NPPs. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
802.
Ken Yanagisawa Fumihiko Imamura Tsutomu Sakakiyama Tadashi Annaka Tomoyoshi Takeda Nobuo Shuto 《Pure and Applied Geophysics》2007,164(2-3):565-576
The present study focuses on evaluation of the maximum and minimum water levels caused by tsunamis as risk factors for operation
and management at nuclear power facilities along the coastal area of Japan. Tsunamis generated by submarine earthquakes are
examined, basing literature reviews and databases of information on historical tsunami events and run-up heights. For simulation
of water level along the coast, a numerical calculation system should be designed with computational regions covering a particular
site. Also the calculation system should be verified by comparison of historical and calculated tsunami heights. At the beginning
of the tsunami assessment, the standard faults, their locations, mechanisms and maximum magnitudes should be carefully estimated
by considering historical earthquake-induced tsunamis and seismo-tectonics at each area. Secondly, the range of errors in
the model parameters should be considered since earthquakes and tsunamis are natural phenomena that involve natural variability
as well as errors in estimating parameters. For these reasons, uncertainty-induced errors should be taken into account in
the process of tsunami assessment with parametric study of the tsunami source model. The element tsunamis calculated by the
standard fault models with the errors would be given for the design. Then, the design tsunami can be selected among the element
tsunamis with the most significant impact, maximum and minimum water levels, on the site, bearing in mind the possible errors
in the numerical calculation system. Finally, the design tsunami is verified by comparison with the run-up heights of historical
tsunamis, ensuring that the design tsunami is selected as the highest of all historical and possible future tsunamis at the
site. 相似文献
803.
E.?Cubellis G.?luongo A.?Marturano A.?MazzarellaEmail author F.?Obrizzo 《Natural Hazards》2005,34(3):263-278
Rank-ordering analysis is applied to the intertimes between seismic events recorded in the Apennine belt between 40–42° N and 14–16° E from the 15th century onwards. It shows a power law capable of governing the intertimes between 1529 and 368 months and another power law which approximates a random simulation, for the intertimes shorter than 368 months. Only the first power law allows the computation of the return period of major events. Earthquakes with the same energy that are aligned according to different power laws imply the presence of two different populations, indicating, in turn, that the physics of seismic phenomena in the region examined is not straightforward, that the stress is probably not unidirectional and that it acts on a non-isotropic medium. The most probable estimated intertime value for the next event is found to be equal to 60 ± 20 years. 相似文献
804.
党中央、国务院作出调整电力结构,加快核电发展的决定,并对铀矿资源保障形势十分关注。据此,中核集团公司提出“铀资源大基地”战略设想。为实施这一战略,需要构建铀矿地质工作新格局,加强管理和队伍建设,深化改革,使我国铀矿地质事业不断迈向新高潮。 相似文献
805.
806.
P. Rajitha R.P. Chhabra N.E. Sabiri Jacques Comiti 《International Journal of Mineral Processing》2006
The free settling velocity of cylinders and disks falling in quiescent Newtonian and power law liquids has been measured over wide ranges of experimental conditions of the particle Reynolds number (10− 5–∼300), power law flow behaviour index (0.31–1) and the length-to-diameter ratio, ∼0.4–∼14. The corresponding range of sphericity is 0.62 to 0.86. An existing drag expression which has been tested extensively for spherical particles falling in Newtonian and in power law fluids has been slightly modified here for non-spherical particles. In particular, the use of this drag expression necessitates a knowledge of an equal volume sphere diameter (to evaluate the Reynolds number and drag coefficient) and the ratio of the surface area to the projected area of a non-spherical particle. With these modifications, the approach outlined here reproduces the present and the literature data for a wide range of non-spherical particles including cones, prisms, needles, cylinders settling in both Newtonian and power law fluids with reasonable levels of accuracy. 相似文献
807.
Comparative Study of the 2:3 and 3:4 Resonant Motion with Neptune: An Application of Symplectic Mappings and Low Frequency Analysis 总被引:2,自引:1,他引:1
The 2:3 and 3:4 exterior mean motion resonances with Neptune are studied by applying symplectic mapping models. The mappings
represent efficiently Poincaré maps for the 3D elliptic restricted three body problem in the neighbourhood of the particular
resonances. A large number of trajectories is studied showing the coexistence of regular and chaotic orbits. Generally, chaotic
motion depletes the small bodies of the effective resonant region in both the 2:3 and 3:4 resonances. Applying a low frequency
spectral analysis of trajectories, we determined the phase space regions that correspond to either regular or chaotic motion.
It is found that the phase space of the 3:4 resonant motion is more chaotic than the 2:3 one. 相似文献
808.
K. Miyazaki 《Journal of Metamorphic Geology》2001,19(2):155-164
This paper examines the spatial statistics of matrix minerals and complex patterned cordierite porphyroblasts in the low‐pressure, high‐temperature (low P/T) Tsukuba metamorphic rocks from central Japan, using a density correlation function. The cordierite‐producing reaction is sillimanite + biotite + quartz = K‐feldspar + cordierite + water. The density correlation function shows that quartz is distributed randomly. However, the density correlation functions of biotite, plagioclase and K‐feldspar show that their spatial distributions are clearly affected by the formation of cordierite porphyroblasts. These observations suggest that cordierite growth occurred through a selective growth mechanism: quartz adjacent to cordierite has a tendency to prevent the growth of cordierite, whereas other matrix minerals adjacent to cordierite have a tendency to enhance the growth of cordierite. The density correlation functions of complex patterned cordierite porphyroblasts show power‐law behaviour. A selective growth mechanism alone cannot explain the origin of the power‐law behaviour. Comparison of the morphology and fractal dimension of cordierite with two‐dimensional sections from a three‐dimensional diffusion‐limited aggregation (DLA) suggests that the formation of cordierite porphyroblasts can be modelled as a DLA process. DLA is the simple statistical model for the universal fractal pattern developed in a macroscopic diffusion field. Diffusion‐controlled growth interacting with a random field is essential to the formation of a DLA‐like pattern. The selective growth mechanism will provide a random noise for the growth of cordierite due to random distribution of quartz. Therefore, a selective growth mechanism coupled with diffusion‐controlled growth is proposed to explain the power‐law behaviour of the density correlation function of complex patterned cordierite. The results in this paper suggest that not only the growth kinetics but also the spatial distribution of matrix minerals affect the progress of the metamorphic reaction and pattern formation of metamorphic rocks. 相似文献
809.
F. D’Alessandro A. A. Deshpande P. M. McCulloch 《Journal of Astrophysics and Astronomy》1997,18(1):5-14
Power spectra of the timing noise observed in 18 southern pulsars have been derived using a novel technique, based on the
CLEAN algorithm. Most of the spectra are well described by a single- or double-component power-law model. Some of these spectra
can be interpreted in the context of one or more of the current timing noise models. The results combined with those obtained
from the time-domain analyses of the timing activity in these pulsars are used to assess the viability of the various theoretical
models of pulsar timing noise. 相似文献
810.
成矿动力系统在混沌边缘分形生长——一种新的成矿理论与方法论(上) 总被引:21,自引:3,他引:18
“成矿动力系统在混沌边缘分形生长”理论是笔者将复杂性理论及非线性科学与矿床地质学相结合 ,对中国扬子古陆周缘六个矿集区的基本范式进行长期系统研究所取得的总结性成果。研究指出 ,成矿系统总体上是开放、远离平衡、时空延展的动力学系统。它们具有复杂性和自组织临界性的内禀基本属性 ,并且在混沌边缘分形生长。该理论以“地质作用与时 空结构是一切地质现象的本质与核心”的自然哲学理念作为根本立足点 ,建立起一种具有普适性的理论框架。然后进一步将其具体化为三大组成部分 ,即 ( 1)矿床的动力学属性 ,( 2 )矿床地质学场 ,( 3 )成矿系统的演化。体现了成矿作用 (其核心为成矿作用动力学 )、空间结构 (矿床地质学场 )和时间结构 (成矿系统的演化 )三位一体的整体耦合与交织 ,从而又使该理论具有包容性。在此基础上进而归纳出“成矿动力系统在混沌边缘分形生长”的 5项判定准则以及表征这些准则的 10项相应的动力学行为特征。最后笔者提出“矿质局部活化导致成矿的发生”的命题 ,拟定了“成矿的发生”的重要科学问题 ,以“元胞非线性网络”(CNN)作为复杂性的范式 ,定量揭示成矿的发生 ,并对矿床在混沌边缘作精确定位 ,对“成矿动力系统在混沌边缘”理论作进一步的延伸、深化与发展。该理论在矿? 相似文献