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101.
M. N. French R. L. Bras W. F. Krajewski 《Stochastic Environmental Research and Risk Assessment (SERRA)》1992,6(1):27-45
A procedure for short-term rainfall forecasting in real-time is developed and a study of the role of sampling on forecast ability is conducted. Ground level rainfall fields are forecasted using a stochastic space-time rainfall model in state-space form. Updating of the rainfall field in real-time is accomplished using a distributed parameter Kalman filter to optimally combine measurement information and forecast model estimates. The influence of sampling density on forecast accuracy is evaluated using a series of a simulated rainfall events generated with the same stochastic rainfall model. Sampling was conducted at five different network spatial densities. The results quantify the influence of sampling network density on real-time rainfall field forecasting. Statistical analyses of the rainfall field residuals illustrate improvement in one hour lead time forecasts at higher measurement densities. 相似文献
102.
104.
V. Zervakis K. Nittis L. Perivoliotis C. Tziavos 《Journal of Atmospheric & Ocean Science》2002,8(2):151-172
Expendable Bathythermograph (XBT) observations collected along a transect across the Eastern Mediterranean are compared with the respective predictions of thermocline structure and variability produced by the POSEIDON system's ocean circulation model. The observations, obtained in the framework of the Mediterranean Forecasting System project, cover a complete annual cycle, at a repetition rate of 1-2 transects per month, thus providing an excellent data set for estimating the model's skill to forecast seasonal variability and mesoscale circulation in the upper 450 m of the ocean. The comparison has revealed that the model adequately predicts the seasonal cycle of the evolution of the thermocline but tends to generate less steep thermoclines than observed. Furthermore, the mesoscale circulation is not accurately predicted. For the latter, data assimilation is considered a necessary step towards the improvement of the system. 相似文献
105.
106.
中国地震倾斜潮观测台网 总被引:1,自引:0,他引:1
系统论述了中国地震倾斜潮观测台网利用地倾斜及其潮汐监测预报地震的科学思路、台网特征、观测精度、映震效能等。重点总结了建网中切合国情、台情的中国独特经验;对第一代、新一代台网记录倾斜同震阶跃信息与前兆异常现象的能力作了对比;还讨论了台网的应用前景。 相似文献
107.
用预报残差最小的逐步回归方法作黄河上游旱涝预测试验 总被引:2,自引:0,他引:2
本文提出用预报残差最小的逐步回归方法作预报,较之传统的逐步回归具有计算简便、适应于小型计算机计算等优点。在作黄河上游旱涝预测试验中表明有较好的效果。 相似文献
108.
109.
The systematic decline of in situ networks for hydrologic measurements has been recognized as a crucial limitation to advancing
hydrologic monitoring in medium to large basins, especially those that are already sparsely instrumented. As a collective
response, sections of the hydrologic community have recently forged partnerships for the development of space-borne missions
for cost-effective, yet global, hydrologic measurements by building upon the technological advancements since the last two
decades. In this article, we review the state-of-the-art on flood monitoring in medium and large ungauged basins where satellite
remote sensing can facilitate development of a cost-effective mechanism. We present our review in the context of the current
hydro-political situation of flood monitoring in flood-prone developing nations situated in international river basins (IRBs).
Given the large number of such basins and the difficulty in acquisition of multi-faceted geophysical data, we argue that the
conventional data-intensive implementation of physically based hydrologic models that are complex and distributed is time-consuming
for global assessment of the utility of proposed global satellite hydrologic missions. A more parsimonious approach is justified
at the tolerable expense of accuracy before such missions begin operation. Such a parsimonious approach can subsequently motivate
the identified international basins to invest greater effort in conventional and detailed hydrologic studies to design a prototype
flood forecasting system in an effort to overcome the hydro-political hurdles to flood monitoring. Through a modeling exercise involving an open-book watershed concept, we demonstrate the value of a parsimonious approach
in understanding the utility of NASA-derived satellite rainfall products. It is critical now that real-world operational flood
forecasting agencies in the under-developed world come forward to collaborate with the research community in order to leverage
satellite rainfall data for greater societal benefit for inhabitants in IRBs. 相似文献
110.
Streamflow drought time series forecasting 总被引:5,自引:2,他引:5
Reza Modarres 《Stochastic Environmental Research and Risk Assessment (SERRA)》2007,21(3):223-233
Drought is considered to be an extreme climatic event causing significant damage both in the natural environment and in human
lives. Due to the important role of drought forecasting in water resources planning and management and the stochastic behavior
of drought, a multiplicative seasonal autoregressive integrated moving average (SARIMA) model is applied to the monthly streamflow
forecasting of the Zayandehrud River in western Isfahan province, Iran. After forecasting 12 leading month streamflow, four
drought thresholds including streamflow mean, monthly streamflow mean, 2-, 5-, 10- and 20-year return period monthly drought
and standardized streamflow index were chosen. Both observed and forecasted streamflow showed a drought period with different
severity in the lead-time. This study also demonstrates the usefulness of SARIMA models in forecasting, water resources planning
and management. 相似文献