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451.
新疆京希-伊尔曼德金矿床矿化类型热液蚀变及流体包裹体证据 总被引:10,自引:0,他引:10
京希_伊尔曼德金矿床位于新疆伊宁县北部。金矿 (化 )体赋存于下石炭统大哈拉军山组下部粗碎屑岩中 ,同时受控于断裂构造和岩性。该矿床形成于浅成低温环境的高硫化体系中。初始强酸性的含金热液流体在沿断裂构造向上迁移时 ,与围岩发生水_岩反应形成由内向外的物理化学梯度变化 ,表现为以硅化 (发育酸性淋滤形成的多孔状石英构造 )、高级泥化和泥化构成蚀变分带。迪开石 +高岭石 +多孔状_硅化石英等热液蚀变矿物构成高级泥化主蚀变。金主要沉淀富集于硅化带和高级泥化带。蚀变矿物组合及流体包裹体资料确定的成矿流体性质为 :酸性 (pH早期为 2~ 3,晚期为 3~ 5 )、低盐度〔w(NaCl) eq<5 %〕及低温 (成矿温度为 180~ 2 70℃ )。 相似文献
452.
Summary Efforts to understand and simulate the global climate in numerical models have led to regional studies of the energy and
water balance. The Baltic Basin provides a continental scale test basin where meteorology, oceanography and hydrology all
can meet. Using a simple conceptual approach, a large-scale hydrological model of the water balance of the total Baltic Sea
Drainage Basin (HBV-Baltic) was used to simulate the basinwide water balance components for the present climate and to evaluate
the land surface components of atmospheric climate models. It has been used extensively in co-operative BALTEX (The Baltic
Sea Experiment) research and within SWECLIM (Swedish Regional Climate Modelling Programme) to support continued regional climate
model development. This helps to identify inconsistencies in both meteorological and hydrological models. One result is that
compensating errors are evident in the snow routines of the atmospheric models studied. The use of HBV-Baltic has greatly
improved the dialogue between hydrological and meteorological modellers within the Baltic Basin research community. It is
concluded that conceptual hydrological models, although far from being complete, play an important role in the realm of continental
scale hydrological modelling. Atmospheric models benefit from the experience of hydrological modellers in developing simpler,
yet more effective land surface parameterisations. This basic modelling tool for simulating the large-scale water balance
of the Baltic Sea drainage basin is the only existing hydrological model that covers the entire basin and will continue to
be used until more detailed models can be successfully applied at this scale.
Received November 24, 2000 Revised April 4, 2001 相似文献
453.
A review of ENSO prediction studies 总被引:10,自引:0,他引:10
M. Latif T. P. Barnett M. A. Cane M. Flügel N. E. Graham H. von Storch J. -S. Xu S. E. Zebiak 《Climate Dynamics》1994,9(4-5):167-179
A hierarchy of ENSO (El Niño/Southern Oscillation) prediction schemes has been developed which includes statistical schemes and physical models. The statistical models are, in general, based on advanced statistical techniques and can be classified into models which use either low-frequency variations in the atmosphere (sea level pressure or surface wind) or upper ocean heat content as predictors. The physical models consist of coupled ocean-atmosphere models of varying degrees of complexity, ranging from simplified coupled models of the shallow water-type to coupled general circulation models. All models, statistical and physical, perform considerably better than the persistence forecast on predicting typical indices of ENSO on lead times of 6 to 12 months. The most successful prediction schemes, the fully physical coupled ocean-atmosphere models, show significant prediction abilities at lead times exceeding one year period. We therefore conclude that ENSO is predictable at least one year in advance. However, all of this applies to gross indices of ENSO such as the Southern Oscillation Index. Despite the demonstrated predictability, little is known about the predictability of specific features known to be associated with ENSO (e.g. Indian Monsoon rainfall, Southern African drought, or even off-equatorial sea surface temperature). Nor has the relative importance for prediction of different regional anomalies or different physical processes yet been established. A seasonal dependence in predictability is well established, but the processes responsible for it are not fully understood. 相似文献
454.
The seismological model was developed initially from the fundamental relationship between earthquake ground motion properties and the seismic moment generated at the source of the earthquake. Following two decades of continuous seismological research in the United States, seismological models which realistically account for both the source and path effects on the seismic shear waves have been developed and their accuracy rigorously verified (particularly in the long and medium period ranges). An important finding from the seismological research by Atkinson and Boore and their co‐investigators is the similarity of the average frequency characteristics of seismic waves generated at the source between the seemingly very different seismic environments of Eastern and Western North America (ENA and WNA, respectively). A generic definition of the average source properties of earthquakes has therefore been postulated, referred to herein as the generic source model. Further, the generic ‘hard rock’ crustal model which is characteristic of ENA and the generic ‘rock’ crustal model characteristic of WNA have been developed to combine with the generic source model, hence enabling simulations to be made of the important path‐related modifications to ground motions arising from different types of crustal rock materials. It has been found that the anelastic contribution to whole path attenuation is consistent between the ENA and WNA models, for earthquake ground motions (response spectral velocities and displacements) in the near and medium fields, indicating that differences in the ENA and WNA motions arise principally from the other forms of path‐related modifications, namely the mid‐crust amplification and the combined effect of the upper‐crust amplification and attenuation, both of which are significant only for the generic WNA ‘rock’ earthquake ground motions. This paper aims to demonstrate the effective utilization of the latest seismological model, comprising the generic source and crustal models, to develop a response spectral attenuation model for direct engineering applications. The developed attenuation model also comprises a source factor and several crustal (wave‐path modification) component factors, and thus has also been termed herein the component attenuation model (CAM). Generic attenuation relationships in CAM, which embrace both ENA and WNA conditions, have been developed using stochastic simulations. The crustal classification of a region outside North America can be based upon regional seismological and geological information. CAM is particularly useful for areas where local strong motion data are lacking for satisfactory empirical modelling. In the companion paper entitled ‘response spectrum modelling for rock sites in low and moderate seismicity regions combining velocity, displacement and acceleration predictions’, the CAM procedure has been incorporated into a response spectrum model which can be used to effectively define the seismic hazard of bedrock sites in low and moderate seismicity regions. This paper and the companion paper constitute the basis of a long‐term objective of the authors, to develop and effectively utilize the seismological model for engineering applications worldwide. 相似文献
455.
Graham C. Archer 《地震工程与结构动力学》2001,30(1):127-145
This paper presents a variation on the component mode technique for the dynamic substructuring of large‐scale structural analysis of building and bridge frames. The principal innovation of the proposed method of dynamic reduction is that the resulting mass matrix of the reduced substructures remains diagonal. As in the component mode technique, the reduction is accomplished by transforming the degrees of freedom in the substructure using boundary shapes and internal shapes. The diagonal mass matrix is achieved by orthogonalization of the boundary shapes to the internal shapes, and a selective row‐by‐row summation of the mass matrix into the diagonal entry (where off‐diagonal terms are unavoidable). To aid in recovering the accuracy of the rigid‐body inertias that is lost in the diagonalization process, additional pseudo‐rigid‐body‐mode shapes are proposed. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献
456.
Among methods for determining the abundance of carbonate minerals in solid samples, dissolution in acid is appealing because it is cheap and can be quick, but it suffers from several sources of uncertainty. The weight loss due to evaporation of water can be corrected for easily by measuring the weight loss from blank vessels as well as sample vessels. However, a further correction, for excess evaporation due to heat liberated by dissolution, is desirable; we show how to calculate it. Certain puzzling results point to a need for further investigation of interfering factors. © 1997 John Wiley & Sons, Ltd. 相似文献
457.
458.
459.
Summary In this paper, findings are presented from a qualitative study of older people's lives in Newcastle upon Tyne, England, to examine the place of the body in everyday meanings and constructions of ageing. Focusing on the home, we show how notions about gendered as well as ageing bodies affect the use and meaning of space. 相似文献
460.
Deon E. Barnes Peter J. Wright Sandra M. Graham Elaine A. Jones-Watson 《Geostandards and Geoanalytical Research》2000,24(2):183-195
The determination of cyanide in various forms is important for industrial processes as well as for environmental investigations and monitoring associated with these processes. The accurate determination of cyanide is difficult for various reasons. Depending on the pH of the solution, cyanide is present both in molecular form (HCN) and ionic form (CN). Furthermore, cyanide is a good complexing reagent and reacts with almost all cations resulting in complexes with widely varying properties, such as stabilities, solubilities and rates of reaction. Cyanide also breaks down in sunlight and air, so that sampling and sample treatment become very important aspects to consider in the methodologies. During the last fifty years the determination of cyanide has been approached from various angles and a myriad of methods has been developed for its determination. This study represents a survey of methods commonly used in industrial laboratories for the analysis of cyanide-containing solutions. An overview of the nomenclature often used for the various forms of cyanides is discussed and the values resulting from a particular analysis will be interpreted. Most common interferences in samples originating from gold processing plants will be discussed. 相似文献