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871.
872.
The evaluation of bioclimatic comfort conditions has very important theoretical meaning and practical value, not only beacause it can help travelers choose their favorate holiday destinations, but also because it can provide scientific foundation for the assessment of urban living environment. It has become a hot topic recently, driven by the flourishing tourism and the improvement of people’s living standard. The research history on assessment of bioclimatic comfort conditions, which may date back almost a century, is divided into three peroids based on a detailed survey of literature related to this topic over the past century. The infulential assessment models in each period are introduced. The historical background, basic idea and applicable conditions for each model are described in detail. The research shows that: ①bioclimatic comfort assessment models have been evolved from simple empirical models limited to space and time into complicated, impersonal, and universal energy balance models, which shows the trend of sophistication and objectivity; ②Today, empirical models are still widely used for the assessment of comfortable climates in China, and thus it is important to select the appropriate ones to make sure they are good for use for a study area or in a particular season; ③there are some problems calling for immediate resolution, such as to develop universal assessment models as well as to explore fine scale assessment techniques; ④the evaluation on featured comfortable climates, which might expand the study area of comfortable climates assessment, is an important research direction in the future. 相似文献
873.
《The Professional geographer》1988,40(2):248-258
Book Reviews in are this Article Northern Waters . Clive Archer and David Scivener , EDS. Principles of Geographical Information Systems for Land Resources Assessment . P. A. Burrough . The Great Lakes: An Environmental Atlas and Resource Book. Environment Canada , United States Environmental Protection Agency , Brock University , AND Northwestern University . Uneven Development in Southern Europe: Studies of Accumulation, Class, Migration and the State. Rays Hudson AND Jim Lewis , EDS. Hazards: Technology and Fairness. Robert W. Kates and Alvin M. Weinberg . The Price of War. Urbanization in Vietnam 1954–85. Nigel Thrift and Dean Forbes . Population Structures and Models: Developments in Spatial Demography. Robert Woods and Philip Rees , EDS. Evaluating Earthquake Hazards in the Los Angeles Region-An Earth-Science Perspective. J. I. Ziony , ed . 相似文献
874.
Saffet Erdogan 《地球表面变化过程与地形》2009,34(3):366-376
Digital elevation models have been used in many applications since they came into use in the late 1950s. It is an essential tool for applications that are concerned with the Earth's surface such as hydrology, geology, cartography, geomorphology, engineering applications, landscape architecture and so on. However, there are some differences in assessing the accuracy of digital elevation models for specific applications. Different applications require different levels of accuracy from digital elevation models. In this study, the magnitudes and spatial patterning of elevation errors were therefore examined, using different interpolation methods. Measurements were performed with theodolite and levelling. Previous research has demonstrated the effects of interpolation methods and the nature of errors in digital elevation models obtained with indirect survey methods for small‐scale areas. The purpose of this study was therefore to investigate the size and spatial patterning of errors in digital elevation models obtained with direct survey methods for large‐scale areas, comparing Inverse Distance Weighting, Radial Basis Functions and Kriging interpolation methods to generate digital elevation models. The study is important because it shows how the accuracy of the digital elevation model is related to data density and the interpolation algorithm used. Cross validation, split‐sample and jack‐knifing validation methods were used to evaluate the errors. Global and local spatial auto‐correlation indices were then used to examine the error clustering. Finally, slope and curvature parameters of the area were modelled depending on the error residuals using ordinary least regression analyses. In this case, the best results were obtained using the thin plate spline algorithm. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
875.
Simple formulas are derived for the dynamic stiffness of pile group foundations subjected to horizontal and rocking dynamic loads. The formulations are based on the construction of a general model of impedance matrices as the condensation of matrices of mass, damping, and stiffness, and on the identification of the values of these matrices on an extensive database of numerical experiments computed using coupled finite element–boundary element models. The formulations obtained can be readily used for the design of both floating piles on homogeneous half‐space and end‐bearing piles and are applicable for a wide range of mechanical and geometrical parameters of the soil and piles, in particular for large pile groups. For the seismic design of a building, the use of the simple formulas rather than a full computational model is shown to induce little error on the evaluation of the response spectra and time histories. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
876.
利用理论和实验重力固体潮模型,充分考虑全球海潮和中国近海潮汐的负荷效应,建立了中国大陆的精密重力潮汐改正模型.结果表明,采用不同的固体潮模型会对重力潮汐结果产生相对变化幅度小于0.06%的差异;在沿海地区海潮负荷的影响约为整个潮汐的4%,而中部地区约为1%,其中中国近海潮汐模型的影响约占整个海潮负荷的10%,内插或外推潮波的负荷约占海潮负荷的3%.通过比较实测的重力数据表明,本文给出的重力潮汐改正模型的精度远远优于0.5×10-8 m·s-2,说明了本文构建的模型的实用性,可为中国大陆高精度重力测量提供有效参考和精密的改正模型. 相似文献
877.
Dejun Yang Tuqiao Zhang Kefeng Zhang Duncan J. Greenwood John P. Hammond Philip J. White 《Journal of Hydrology》2009,370(1-4):177-190
Models for water transfer in the crop–soil system are key components of agro-hydrological models for irrigation, fertilizer and pesticide practices. Many of the hydrological models for water transfer in the crop–soil system are either too approximate due to oversimplified algorithms or employ complex numerical schemes. In this paper we developed a simple and sufficiently accurate algorithm which can be easily adopted in agro-hydrological models for the simulation of water dynamics. We used a dual crop coefficient approach proposed by the FAO for estimating potential evaporation and transpiration, and a dynamic model for calculating relative root length distribution on a daily basis. In a small time step of 0.001 d, we implemented algorithms separately for actual evaporation, root water uptake and soil water content redistribution by decoupling these processes. The Richards equation describing soil water movement was solved using an integration strategy over the soil layers instead of complex numerical schemes. This drastically simplified the procedures of modeling soil water and led to much shorter computer codes. The validity of the proposed model was tested against data from field experiments on two contrasting soils cropped with wheat. Good agreement was achieved between measurement and simulation of soil water content in various depths collected at intervals during crop growth. This indicates that the model is satisfactory in simulating water transfer in the crop–soil system, and therefore can reliably be adopted in agro-hydrological models. Finally we demonstrated how the developed model could be used to study the effect of changes in the environment such as lowering the groundwater table caused by the construction of a motorway on crop transpiration. 相似文献
878.
Rainfall and Obtaining Information Regarding Earthquake Development Processes from Groundwater Level
Many factors can cause changes of groundwater level, such as the development process of an earthquake, rainfall, solid earth tides etc. Among these we are interested in information regarding earthquake development processes. Eliminating the influence of various disturbance factors is an effective way to obtain seismic development process information contained in the groundwater level. This paper provides two different ways to remove the rainfall effect, and compares the two methods by means of correlation analysis. Furthermore, based on these a logistic regression model is established to describe the seismicity level. 相似文献
879.
Shuffled Complex Evolution model calibrating algorithm: enhancing its robustness and efficiency 总被引:1,自引:0,他引:1
Shuffled Complex Evolution—University of Arizona (SCE‐UA) has been used extensively and proved to be a robust and efficient global optimization method for the calibration of conceptual models. In this paper, two enhancements to the SCE‐UA algorithm are proposed, one to improve its exploration and another to improve its exploitation of the search space. A strategically located initial population is used to improve the exploration capability and a modification to the downhill simplex search method enhances its exploitation capability. This enhanced version of SCE‐UA is tested, first on a suite of test functions and then on a conceptual rainfall‐runoff model using synthetically generated runoff values. It is observed that the strategically located initial population drastically reduces the number of failures and the modified simplex search also leads to a significant reduction in the number of function evaluations to reach the global optimum, when compared with the original SCE‐UA. Thus, the two enhancements significantly improve the robustness and efficiency of the SCE‐UA model calibrating algorithm. Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
880.
Roberta-Serena Blasone Jasper A. Vrugt Henrik Madsen Dan Rosbjerg Bruce A. Robinson George A. Zyvoloski 《Advances in water resources》2008
In the last few decades hydrologists have made tremendous progress in using dynamic simulation models for the analysis and understanding of hydrologic systems. However, predictions with these models are often deterministic and as such they focus on the most probable forecast, without an explicit estimate of the associated uncertainty. This uncertainty arises from incomplete process representation, uncertainty in initial conditions, input, output and parameter error. The generalized likelihood uncertainty estimation (GLUE) framework was one of the first attempts to represent prediction uncertainty within the context of Monte Carlo (MC) analysis coupled with Bayesian estimation and propagation of uncertainty. Because of its flexibility, ease of implementation and its suitability for parallel implementation on distributed computer systems, the GLUE method has been used in a wide variety of applications. However, the MC based sampling strategy of the prior parameter space typically utilized in GLUE is not particularly efficient in finding behavioral simulations. This becomes especially problematic for high-dimensional parameter estimation problems, and in the case of complex simulation models that require significant computational time to run and produce the desired output. In this paper we improve the computational efficiency of GLUE by sampling the prior parameter space using an adaptive Markov Chain Monte Carlo scheme (the Shuffled Complex Evolution Metropolis (SCEM-UA) algorithm). Moreover, we propose an alternative strategy to determine the value of the cutoff threshold based on the appropriate coverage of the resulting uncertainty bounds. We demonstrate the superiority of this revised GLUE method with three different conceptual watershed models of increasing complexity, using both synthetic and real-world streamflow data from two catchments with different hydrologic regimes. 相似文献