全文获取类型
收费全文 | 1100篇 |
免费 | 66篇 |
国内免费 | 38篇 |
专业分类
测绘学 | 64篇 |
大气科学 | 57篇 |
地球物理 | 352篇 |
地质学 | 568篇 |
海洋学 | 50篇 |
天文学 | 45篇 |
综合类 | 11篇 |
自然地理 | 57篇 |
出版年
2024年 | 4篇 |
2023年 | 3篇 |
2022年 | 43篇 |
2021年 | 56篇 |
2020年 | 64篇 |
2019年 | 42篇 |
2018年 | 115篇 |
2017年 | 95篇 |
2016年 | 117篇 |
2015年 | 68篇 |
2014年 | 96篇 |
2013年 | 128篇 |
2012年 | 68篇 |
2011年 | 66篇 |
2010年 | 41篇 |
2009年 | 36篇 |
2008年 | 27篇 |
2007年 | 15篇 |
2006年 | 20篇 |
2005年 | 4篇 |
2004年 | 15篇 |
2003年 | 7篇 |
2002年 | 4篇 |
2001年 | 9篇 |
2000年 | 4篇 |
1999年 | 3篇 |
1998年 | 3篇 |
1997年 | 2篇 |
1996年 | 3篇 |
1995年 | 2篇 |
1993年 | 1篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 6篇 |
1989年 | 3篇 |
1986年 | 2篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1979年 | 1篇 |
1977年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1974年 | 3篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1971年 | 4篇 |
1969年 | 1篇 |
排序方式: 共有1204条查询结果,搜索用时 15 毫秒
101.
Natural Resources Research - The operation of large-scale ore-forming processes triggers the development of neighboring mineral deposits of the same or related types in a metallogenic province.... 相似文献
102.
Mohammady Majid Moradi Hamid Reza Zeinivand Hossein Temme A.J.A.M. Yazdani Mohammad Reza Pourghasemi Hamid Reza 《Theoretical and Applied Climatology》2018,133(1-2):459-471
Theoretical and Applied Climatology - Land use change is an important determinant of hydrological processes and is known to affect hydrological parameters such as runoff volume, flood frequency,... 相似文献
103.
Mohammad Parsa Abbas Maghsoudi Emmanuel John M. Carranza Mahyar Yousefi 《Natural Resources Research》2017,26(4):443-455
In this study, stream sediment geochemical data have been subjected to robust principal components analysis (RPCA) and singularity mapping (SM) to enhance and map significant multivariate geochemical anomalies (i.e., mineralization-related) in Ahar area, NW Iran. The RPCA was applied to (a) account for the compositional nature of stream sediment geochemical data using suitable log-ratio transformation, (b) modulate the effect of outliers in component estimation and (c) derive a multivariate geochemical footprint of mineralization. The SM was applied to extract anomalous patterns of the multivariate geochemical footprint of mineralization. The exploration targets were then delineated using Student’s t-statistics analysis. The correlations of mapped exploration targets with the known mineral occurrences and mineralization-related patterns were further evaluated using normalized density index and overall accuracy analyses. 相似文献
104.
Azmi Mohammad Rüdiger Christoph Walker Jeffrey P. 《Theoretical and Applied Climatology》2017,130(1-2):497-509
Theoretical and Applied Climatology - A large range of indices and proxies are available to describe the water stress conditions of an area subject to different applications, which have varying... 相似文献
105.
Special Economic Zones (SEZs) are important vectors of neoliberal globalization in India. Despite facing widespread resistance against the proposed land acquisition for these zones, they are still being promoted across the country. We argue that the wealth redistribution to the country's elites and the fractured resistance movements enable neoliberalism and its practices to grow in the countryside. Using a private sector SEZ in Gurgaon as a case study, this article explores how special economic zoning, as a neoliberal policy, has been implicated in the spatialized production of poverty. We also show that the main actors who promote neoliberalism in India (the state and the large‐scale urban private sector) have found a seemingly unlikely ally in rural India in the form of farmers with large landholdings, rural elites who are willing to let go of their land under certain conditions. The data for the article was collected in India in 2009–10. 相似文献
106.
Alireza Garakaninezhad Morteza Bastami Mohammad Reza Soghrat 《Journal of Seismology》2017,21(6):1505-1516
The evaluation of seismic risk of spatially distributed systems requires the spatial correlation model for ground motion intensity measures. This study investigates the spatial correlation of four earthquakes recorded in northern Iran. The intra-event spatial correlation for both horizontal and vertical components of spectral acceleration at eight periods in the range of 0.0–3.0 s is estimated using geostatistical tools. An exponential form is chosen to fit experimental semivariograms, and the correlation ranges of spectral accelerations as a function of period are derived. The results show similar trend of correlation ranges for both components. It should be mentioned that the ranges for the vertical component, in general, are higher than those observed for the horizontal one. For both components, the correlation ranges as a function of period are divided into three segments. The first and the third one are increasing while the second one is decreasing with increasing period. 相似文献
107.
Prediction of factors affecting water resources systems is important for their design and operation. In hydrology, wavelet analysis (WA) is known as a new method for time series analysis. In this study, WA was combined with an artificial neural network (ANN) for prediction of precipitation at Varayeneh station, western Iran. The results obtained were compared with the adaptive neural fuzzy inference system (ANFIS) and ANN. Moreover, data on relative humidity and temperature were employed in addition to rainfall data to examine their influence on precipitation forecasting. Overall, this study concluded that the hybrid WANN model outperformed the other models in the estimation of maxima and minima, and is the best at forecasting precipitation. Furthermore, training and transfer functions are recommended for similar studies of precipitation forecasting. 相似文献
108.
Vahid Mahboub Mohammad Saadatseresht Alireza A. Ardalan 《Studia Geophysica et Geodaetica》2017,61(1):19-34
An applicable algorithm for Total Kalman Filter (TKF) approach is proposed. Meanwhile, we extend it to the case in which we can consider arbitrary weight matrixes for the observation vector, the random design matrix and possible correlation between them. Also the updated dispersion matrix of the predicted unknown is given. This approach makes use of condition equations and straightforward variance propagation rules. It is applicable to data fusion within a dynamic errors-in-variables (DEIV) model, which usually appears in the determination of the position and attitude of mobile sensors. Then, we apply for the first time the TKF algorithm and its extended version named WTKF to a DEIV model and compare the results. The results show the efficiency of the proposed WTKF algorithm. In particular in the case of large weights, WTKF shows approximately 25% improvement in contrast to TKF approach. 相似文献
109.
110.
Mahsa H. Kashani Mohammad Ali Ghorbani Yagob Dinpasho Sedaghat Shahmorad Zbigniew W. Kundzewicz 《Water Resources》2017,44(4):568-578
Although the Volterra models are non-parsimonious ones, they are being used because they can mimic dynamics of complex systems. However, applying and identification of the Volterra models using data may result in overfitting problem and uncertainty. In this investigation we evaluate capability of different wavelet forms for decomposing and compressing the Volterra kernels in order to overcome this problem by reducing the number of the model coefficients to be estimated and generating smooth kernels. A simulation study on a rainfall?runoff process over the Cache River watershed showed that the method performance is successful due to multi-resolution capacity of the wavelet analysis and high capability of the Volterra model. The results also revealed that db2 and sym2 wavelets have the same high potential in improving the linear Volterra model performance. However, QS wavelet was more successful in yielding smooth kernels. Moreover, the probability of overfitting while identifying the nonlinear Volterra model may be less than the linear model. 相似文献