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101.
Soil organic carbon (SOC) is an important aspect of soil quality and plays an imperative role in soil productivity in the agriculture ecosystems. The present study was applied to estimate the SOC stock using space-borne satellite data (Landsat 4–5 Thematic Mapper [TM]) and ground verification in the Medinipur Block, Paschim Medinipur District and West Bengal in India. In total, 50 soil samples were collected randomly from the region according to field surveys using a hand-held Global Positioning System (GPS) unit to estimate the surface SOC concentrations in the laboratory. Bare soil index (BSI) and normalized difference vegetation ndex (NDVI) were explored from TM data. The satellite data-derived indices were used to estimate spatial distribution of SOC using multivariate regression model. The regression analysis was performed to determine the relationship between SOC and spectral indices (NDVI and BSI) and compared the observed SOC (field measure) to predict SOC (estimated from satellite images). Goodness fit test was performed to determine the significance of the relationship between observed and predicted SOC at p ≤ 0.05 level. The results of regression analysis between observed SOC and NDVI values showed significant relationship (R2 = 0.54; p < 0.0075). A significant statistical relationship (r = ?0.72) was also observed between SOC and BSI. Finally, our model showed nearly 71% of the variance of SOC distribution could be explained by SOC and NDVI values. The information from this study has advanced our understanding of the ongoing ecological development that affects SOC dissemination and might be valuable for effective soil management. 相似文献
102.
Zekri Hamid Cohen David R. Mokhtari Ahmad Reza Esmaeili Abbas 《Natural Resources Research》2019,28(3):867-868
Natural Resources Research - The original version of this article unfortunately contained a mistake in the second part of Table 3. The data in last four rows of Table 3, i.e.,... 相似文献
103.
Eskandari Saeedeh Amiri Mahdis Sãdhasivam Nitheshnirmal Pourghasemi Hamid Reza 《Natural Hazards》2020,104(1):305-327
Natural Hazards - The forest fire hazard mapping using the accurate models in the fire-prone areas has particular importance to predict the future fire occurrence and allocate the resources for... 相似文献
104.
Leung Juliana Y. Li Liangping Morgan Eugene Emami-Meybodi Hamid 《Mathematical Geosciences》2020,52(8):975-976
Mathematical Geosciences - 相似文献
105.
Driss Khattach Hamid Mraoui Driss Sbibih Touria Chennouf 《Comptes Rendus Geoscience》2006,338(8):521-526
The multiscale wavelet analysis has been applied to the gravity data from northeastern Morocco to map the major geological contacts, such us faults. Hence, the faults affecting the survey area were outlined with their importance level and dip direction. Seismic data confirm these results and testify the efficiency of this method, particularly in studying structure of plains. The structural map established is a very useful document in the planning of natural resources investigations (i.e. water, mines) to be undertaken in the area of study. To cite this article: D. Khattach et al., C. R. Geoscience 338 (2006). 相似文献
106.
Taheri Shahraiyni Hamid Karimi Khadijeh Habibi Nokhandan Majid Hafezi Moghadas Naser 《Arabian Journal of Geosciences》2015,8(4):2095-2110
Arabian Journal of Geosciences - Dust storms are one of the major environmental disasters in the arid regions of Middle East, occurring in very high frequency. As a result, monitoring dust storms... 相似文献
107.
108.
Marc Leisenring Hamid Moradkhani 《Stochastic Environmental Research and Risk Assessment (SERRA)》2011,25(2):253-270
Using the U.S. National Weather Service’s SNOW-17 model, this study compares common sequential data assimilation methods,
the ensemble Kalman filter (EnKF), the ensemble square root filter (EnSRF), and four variants of the particle filter (PF),
to predict seasonal snow water equivalent (SWE) within a small watershed near Lake Tahoe, California. In addition to SWE estimation,
the various data assimilation methods are used to estimate five of the most sensitive parameters of SNOW-17 by allowing them
to evolve with the dynamical system. Unlike Kalman filters, particle filters do not require Gaussian assumptions for the posterior
distribution of the state variables. However, the likelihood function used to scale particle weights is often assumed to be
Gaussian. This study evaluates the use of an empirical cumulative distribution function (ECDF) based on the Kaplan–Meier survival
probability method to compute particle weights. These weights are then used in different particle filter resampling schemes.
Detailed analyses are conducted for synthetic and real data assimilation and an assessment of the procedures is made. The
results suggest that the particle filter, especially the empirical likelihood variant, is superior to the ensemble Kalman
filter based methods for predicting model states, as well as model parameters. 相似文献
109.
Pierre Bouilhol Urs Schaltegger Massimo Chiaradia Maria Ovtcharova Andreas Stracke Jean-Pierre Burg Hamid Dawood 《Chemical Geology》2011,280(3-4):243-256
The combination of age determination and geochemical tracers allows understanding the source evolution during magmatism. We studied the Sapat Complex, in the exhumed Cretaceous Kohistan Paleo-Island Arc, to reconstruct the formation of the juvenile lower arc crust and the evolution of the mantle source during arc magmatism. High precision ID-TIMS U/Pb dating on zircon, shows that a protracted period of magmatic accretion formed the Sapat Complex between 105 and 99 Ma. Since continued melt percolation processes that formed the lower crust obscured the original bulk rock Nd–Pb–Sr isotopic composition, we rely on the Hf isotopic composition of zircons of different ages to unravel the source evolution. Nd and Pb bulk isotopic compositions coupled with Hf isotopic composition on zircons allow reconstructing a geodynamical scenario for the Sapat Complex, and the Cretaceous history of the Arc. We suggest that trenchward migration of the hot mantle source at 105 Ma explains the small heterogeneous εHf signal between + 14 and + 16. This heterogeneity vanished within ca. 2 million years, and the εHf of the source evolved from + 16 to + 14 at 99 Ma. Integrated to the Kohistan Cretaceous history, which has a baseline of εHf ≈ 14, these data pinpoint two geodynamical events, with slab retreat and the formation of the Sapat Complex followed by splitting of the Kohistan island arc at 85 Ma. 相似文献
110.
Hamid Reza Pakzad Kurosh Javidan Mouloud Tribeche 《Astrophysics and Space Science》2014,352(1):185-191
The propagation of cylindrical and spherical electron acoustic (EA) shock waves in unmagnetized plasmas consisting of cold fluid electrons, hot electrons obeying a superthermal distribution and stationary ions, has been investigated. The standard reductive perturbation method (RPM) has been employed to derive the cylindrical/spherical Korteweg-de-Vries-Burger (KdVB) equation which governs the dynamics of the EA shock structures. The effects of nonplanar geometry, plasma kinematic viscosity and electron suprathermality on the temporal evolution of the cylindrical and spherical EA shock waves are numerically examined. 相似文献