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991.
There are a number of sources of uncertainty in regional climate change scenarios. When statistical downscaling is used to obtain regional climate change scenarios, the uncertainty may originate from the uncertainties in the global climate models used, the skill of the statistical model, and the forcing scenarios applied to the global climate model. The uncertainty associated with global climate models can be evaluated by examining the differences in the predictors and in the downscaled climate change scenarios based on a set of different global climate models. When standardized global climate model simulations such as the second phase of the Coupled Model Intercomparison Project (CMIP2) are used, the difference in the downscaled variables mainly reflects differences in the climate models and the natural variability in the simulated climates. It is proposed that the spread of the estimates can be taken as a measure of the uncertainty associated with global climate models. The proposed method is applied to the estimation of global-climate-model-related uncertainty in regional precipitation change scenarios in Sweden. Results from statistical downscaling based on 17 global climate models show that there is an overall increase in annual precipitation all over Sweden although a considerable spread of the changes in the precipitation exists. The general increase can be attributed to the increased large-scale precipitation and the enhanced westerly wind. The estimated uncertainty is nearly independent of region. However, there is a seasonal dependence. The estimates for winter show the highest level of confidence, while the estimates for summer show the least.  相似文献   
992.
This article studies the response of the distribution pattern and the physiological characteristics of the ecosystem to the spontaneous precipitation and the interaction between vegetation and the atmosphere on multiple scales in arid and semi-arid zones, based on measured data of the ecological physiological parameters in the Ordas Plateau of northern China. The results show that the vegetation biomass and the energy use efficiency of photosynthesis are especially sensitive to the annual precipitation; strong and complex interactions exist between the vegetation and the atmosphere on multiple scales leading to supernormal thermal heterogeneity of the underlying surface, the strong vortex movement and turbulence. This study can facilitate understanding of the land surface processes and the influences of global climate change as well as human activities on the human environment in the arid and semi-arid zones. It also aids in improving the parameterization schemes of turbulent fluxes of a heterogeneous underlying surface for land surface processes in climate models.  相似文献   
993.
Numerical Simulation of Long-Term Climate Change in East Asia   总被引:1,自引:0,他引:1       下载免费PDF全文
A 10-yr regional climate simulation was performed using the fifth-generation PSU/NCAR Mesoscale Model Version 3 (MM5V3) driven by large-scale NCEP/NCAR reanalyses. Simulations of winter and summer mean regional climate features were examined against observations. The results showed that the model could well simulate the 10-yr winter and summer mean circulation, temperature, and moisture transport at middle and low levels. The simulated winter and summer mean sea level pressure agreed with the NCAR/NCEP reanalysis data. The model could well simulate the distribution and intensity of winter mean precipitation rates as well as the distribution of summer mean precipitation rates, but it overestimated the summer mean precipitation over North China. The model's ability to simulate the regional climate change in winter was superior to that in summer. In addition, the model could simulate the inter-annual variation of seasonal precipitation and surface air temperature. Geopotential heights and temperature at middle and high levels between simulations and observations exhibited high anomaly correlation coefficients. The model also showed large variability to simulate the regional climate change associated with the El Nino events. The MM5V3 well simulated the anomalies of summer mean precipitation in 1992 and 1995, while it demonstrated much less ability to simulate that in 1998. Generally speaking, the MM5V3 is capable of simulating the regional climate change, and could be used for long-term regional climate simulation.  相似文献   
994.
CLIMATE CHANGE: LONG-TERM TRENDS AND SHORT-TERM OSCILLATIONS   总被引:2,自引:0,他引:2  
Identifying the Northern Hemisphere (NH) temperature reconstruction and instrumental data for the past 1000 years shows that climate change in the last millennium includes long-term trends and various oscillations. Two long-term trends and the quasi-70-year oscillation were detected in the global temperature series for the last 140 years and the NH millennium series. One important feature was emphasized that temperature decreases slowly but it increases rapidly based on the analysis of different series. Benefits can be obtained of climate change from understanding various long-term trends and oscillations. Millennial temperature proxies from the natural climate system and time series of nonlinear model system are used in understanding the natural climate change and recognizing potential benefits by using the method of wavelet transform analysis. The results from numerical modeling show that major oscillations contained in numerical solutions on the interdecadal timescale are consistent with that of natural proxies. It seems that these oscillations in the climate change are not directly linked with the solar radiation as an external forcing. This investigation may conclude that the climate variability at the interdecadal timescale strongly depends on the internal nonlinear effects in the climate system.  相似文献   
995.
夏季干旱逐日动态监测指数研究   总被引:1,自引:3,他引:1  
根据造成干旱的主要气象因素是降水持续偏少、气温偏高、蒸发量大的思路,利用逐日降水量和逐日最高气温资料进行实验研究,设计了夏季干旱的逐日动态监测指数.该指数可根据每日最新日降水值和日最高气温值的变化,及时给出影响干旱程度变化的主要气象因素的变化,使干旱监测具有实时性、敏感性和连贯性.利用该指数对2003年江西夏季发生的特大干旱进行逐日跟踪动态监测,监测结果表明该指数可以实时反映实际干旱的变化趋势.  相似文献   
996.
土地利用动态遥感监测成果应用现状及信息共享策略   总被引:8,自引:0,他引:8  
新一轮国土资源大调查工程中土地利用动态遥感监测项目,经过六年多的运行取得了丰富的成果和第一手数据资料,是土地管理工作中重要的数据资源,本文通过对土地利用动态遥感监测成果内容和特点、应用现状及存在问题的分析,提出成果应用建议。  相似文献   
997.
我国土地资源遥感调查与监测技术体系建设构想   总被引:1,自引:0,他引:1  
本文在全面分析总结我国土地资源遥感调查与监测历程的基础上,提出了我国土地资源遥感调查与监测的技术框架与体系以及主要问题和关键技术。研究结果表明我国土地资源遥感调查与监测体系建立已经极为迫切,其目标在于建立土地资源遥感调查与监测本底库和动态库,形成多系统组成的技术体系框架。  相似文献   
998.
基于Terra/MODIS的沙尘暴业务化遥感监测研究   总被引:1,自引:0,他引:1  
探讨了以MODIS为数据源进行沙尘暴监测的业务化技术流程及方法。以2003年4月9~11日连续发生在我国西北部特大沙尘暴为例,进行了沙尘信息提取及等级划分的示例研究,并与已经业务化运行的气象卫星(NOAA-16、风云1C气象卫星)的结果进行了相关比较。结果表明,该研究为卫星遥感监测沙尘提供了新的数据源和监测途径。  相似文献   
999.
基于RS对云南边境地区土地覆盖现状及变化研究   总被引:5,自引:2,他引:5  
 土地利用/覆盖变化研究是全球变化研究的热点之一。应用遥感、GIS技术及数理统计学的方法,利用1976年MSS和2004年TM二个时期的遥感影像数据,对云南边境地区的土地覆盖动态变化进行监测研究,并对变化的时空特征进行了分析。结果表明,土地覆盖现状以森林和裸岩地为主,土地利用/覆盖变化的主要方向是林地向裸地和耕地转化。  相似文献   
1000.
 RS和GIS支持下的盐池县生态景观格局动态变化研究   总被引:2,自引:1,他引:2  
基于遥感(RS)和地理信息系统(GIS)技术,以Landsat TM/ETM图像为基本数据源,综合运用景观生态学理论和方法,对我国典型农牧交错生态脆弱区宁夏盐池县1991~2000年生态景观格局动态变化进行了研究。结果表明: 盐池县各景观类型都发生了很大程度的消长变化,景观格局处于快速调整和不稳定发展阶段,但生态景观基质还是草地,景观格局始终呈农牧交错结构。  相似文献   
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