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71.
降雨型浅层滑坡危险性预测模型 总被引:5,自引:0,他引:5
通过分析SHALSTAB和TRIGRS等浅层滑坡物理确定性模型存在的问题,提出了基于降雨入渗动态守恒的瞬态降雨入渗模型,该模型考虑了初期降雨过程、降雨历程以及饱和非饱和入渗过程,证明了SHALSTAB模型是该模型的特殊形式,并克服了TRIGRS模型参数繁多及一维入渗路径的问题.将无限边坡模型、瞬态降雨入渗模型和GIS进行耦合,研发了可用于大范围降雨型浅层滑坡危险性预测的集成系统,根据边坡的地质条件、地形参数和降雨特征即可对降雨条件下浅层滑坡的危险性进行评估. 相似文献
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73.
Soil erosion prediction using the Revised Universal Soil Loss Equation (RUSLE) in a GIS framework,Chania, Northwestern Crete,Greece 总被引:7,自引:0,他引:7
Soil erosion is a growing problem in southern Greece and particularly in the island of Crete, the biggest Greek island with
great agricultural activity. Soil erosion not only decreases agricultural productivity, but also reduces the water availability.
In the current study, an effort to predict potential annual soil loss has been conducted. For the prediction, the Revised
Universal Soil Loss Equation (RUSLE) has been adopted in a Geographical Information System framework. The RUSLE factors were
calculated (in the form of raster layers) for the nine major watersheds which cover the northern part of the Chania Prefecture.
The R-factor was calculated from monthly and annual precipitation data. The K-factor was estimated using soil maps available from the Soil Geographical Data Base of Europe at a scale of 1:1,000,000.
The LS-factor was calculated from a 30-m digital elevation model. The C-factor was calculated using Remote Sensing techniques. The P-factor in absence of data was set to 1. The results show that an extended part of the area is undergoing severe erosion.
The mean annual soil loss is predicted up to ∼200 (t/ha year−1) for some watersheds showing extended erosion and demanding the attention of local administrators. 相似文献
74.
空间分析方法、应用模型与GIS的关系 总被引:4,自引:0,他引:4
首先阐述了空间分析和应用模型的基本概念,进而从地理信息处理系统的功能入手,分析了空间分析、应用模型和GIS的关系,最后指出加强应用模型与GIS的结合以及增强GIS的基本空间分析功能是增强GIS整体功能的二个最有效的方法. 相似文献
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76.
ORACLE空间数据库的对象-关系模式初探——兼议关系数据库和面向对象数据库在GIS中的应用 总被引:13,自引:0,他引:13
传统的关系数据库在GIS的应用中主要存在以下问题: 除数据类型简单, 不能很好地表达非结构化数据外, 也难以表示GIS中具有复杂结构的数据; 关系模型简单, 不能表达数据之间的层次, 继承、聚合、泛化或特化等在GIS广泛使用的关系; 与数据操纵语言如SQL和通用程序设计语言, 特别是目前流行的面向对象设计语言之间失配.采用面向对象技术可以较好地解决上述问题.ORACLE的空间数据库在传统的关系数据库上进行了面向对象的扩展, 即所谓对象-关系模式, 其核心在于增加了名为SDO-GEOMETRY的对象数据类型, 用于存储几何实体.ORACLE的空间数据库的应用示例表明: 以面向对象的形式表示空间数据比之于关系数据库中存放大量无意义的坐标有着很大的优势, 同时, 它在复合对象的表达方面, 在对于空间关系的处理方面都非常有效 相似文献
77.
A landslide susceptibility zonation (LSZ) map helps to understand the spatial distribution of slope failure probability in
an area and hence it is useful for effective landslide hazard mitigation measures. Such maps can be generated using qualitative
or quantitative approaches. The present study is an attempt to utilise a multivariate statistical method called binary logistic
regression (BLR) analysis for LSZ mapping in part of the Garhwal Lesser Himalaya, India, lying close to the Main Boundary
Thrust (MBT). This method gives the freedom to use categorical and continuous predictor variables together in a regression
analysis. Geographic Information System has been used for preparing the database on causal factors of slope instability and
landslide locations as well as for carrying out the spatial modelling of landslide susceptibility. A forward stepwise logistic
regression analysis using maximum likelihood estimation method has been used in the regression. The constant and the coefficients
of the predictor variables retained by the regression model have been used to calculate the probability of slope failure for
the entire study area. The predictive logistic regression model has been validated by receiver operating characteristic curve
analysis, which has given 91.7% accuracy for the developed BLR model. 相似文献
78.
79.
80.
A comparison of the GIS based landslide susceptibility assessment methods: multivariate versus bivariate 总被引:30,自引:0,他引:30
The purpose of this study is to evaluate and to compare the results of multivariate (logical regression) and bivariate (landslide susceptibility) methods in Geographical Information System (GIS) based landslide susceptibility assessment procedures. In order to achieve this goal the Asarsuyu catchment in NW Turkey was selected as a test zone because of its well-known landslide occurrences interfering with the E-5 highway mountain pass.Two methods were applied to the test zone and two separate susceptibility maps were produced. Following this a two-fold comparison scheme was implemented. Both methods were compared by the Seed Cell Area Indexes (SCAI) and by the spatial locations of the resultant susceptibility pixels.It was found that both of the methods converge in 80% of the area; however, the weighting algorithm in the bivariate technique (landslide susceptibility method) had some severe deficiencies, as the resultant hazard classes in overweighed areas did not converge with the factual landslide inventory map. The result of the multivariate technique (logical regression) was more sensitive to the different local features of the test zone and it resulted in more accurate and homogeneous susceptibility maps. 相似文献