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991.
992.
Gong Jialong 《海洋学报(英文版)》1989,8(3):379-390
Sea-ice is an important operational item for real timely monitoring and forecasting marine environment of China. This paper introduces an operational method of satellite remote sensing to monitor sea- ice using quantitative data of NOAA, and its contents include computer processing of AVHRR sounding data of NOAA and its program design, imagery processing of sea-ice imagery from satellite and their thematic analysis. The sea-ice satellite colour imageries processed via this software system are able to interpret sea-ice pattern, characterizing it by thickness, maximum position of ice boundary, floe concentration and dynamic process of ice changing. At the same time, analyses of the ice condition of the Bohai Sea for the two-year period (1986-1988) as monitored by satellite have been summarized. 相似文献
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994.
Land subsidence induced by excessive groundwater withdrawal has caused serious social, geological, and environmental problems in Beijing. Rapid increases in population and economic development have aggravated the situation. Monitoring and prediction of ground settlement is important to mitigate these hazards. In this study, we combined persistent-scatterer interferometric synthetic aperture radar with Grey system theory to monitor and predict land subsidence in the Beijing plain. Land subsidence during 2003–2014 was determined based on 39 ENVISAT advanced synthetic aperture radar (ASAR) images and 27 RadarSat-2 images. Results were consistent with global positioning system, leveling measurements at the point level and TerraSAR-X subsidence maps at the regional level. The average deformation rate in the line-of-sight was from ?124 to 7 mm/year. To predict future subsidence, the time-series deformation was used to build a prediction model based on an improved Grey-Markov model (IGMM), which adapted the conventional GM(1,1) model by utilizing rolling mechanism and integrating a k-means clustering method in Markov-chain state interval partitioning. Evaluation of the IGMM at both point level and regional scale showed good accuracy (root-mean-square error <3 mm; R2 = 0.94 and 0.91). Finally, land subsidence in 2015–2016 was predicted, and the maximum cumulative deformation will reach 1717 mm by the end of 2016. The promising results indicate that this method can be used as an alternative to the conventional numerical and empirical models for short-term prediction when there is lack of detailed geological or hydraulic information. 相似文献
995.
Using Spatial Analysis to Understand the Spatial Heterogeneity of Disability Employment in China 总被引:2,自引:0,他引:2 下载免费PDF全文
Yilan Liao Jinfeng Wang Wei Du Bingbo Gao Xin Liu Gong Chen Xinming Song Xiaoying Zheng 《Transactions in GIS》2017,21(4):647-660
During the formulation of employment disability policy, policymakers are often interested in regional variations of disability employment. Decision‐makers are required to distinguish between various geographical factors. However, few previous studies take spatial heterogeneity into account and most of them conducted only a qualitative analysis. Geographical detectors based on spatial variation analyses of identified factors were applied in the study to establish connections between regional features and the disability employment rate, and to identify the city groups with significantly higher and lower percentage rates of disability employment. It is the first application of spatial statistics in studying the employment problem of the disabled. The findings can help the government formulate reasonable adjustments to both job opportunities for, and work roles of, disabled people. 相似文献
996.
Yihe Fang Haishan Chen Zhiqiang Gong Fangshu Xu Chunyu Zhao 《Acta Meteorologica Sinica》2017,31(6):1085-1095
Based on summer precipitation hindcasts for 1991–2013 produced by the Beijing Climate Center Climate System Model (BCC_CSM), the relationship between precipitation prediction error in northeastern China (NEC) and global sea surface temperature is analyzed, and dynamic–analogue prediction is carried out to improve the summer precipitation prediction skill of BCC_CSM, through taking care of model historical analogue prediction error in the real-time output. Seven correction schemes such as the systematic bias correction, pure statistical correction, dynamic–analogue correction, and so on, are designed and compared. Independent hindcast results show that the 5-yr average anomaly correlation coefficient (ACC) of summer precipitation is respectively improved from –0.13/0.15 to 0.16/0.24 for 2009–13/1991–95 when using the equally weighted dynamic–analogue correction in the BCC_CSM prediction, which takes the arithmetical mean of the correction based on regional average error and that on grid point error. In addition, probabilistic prediction using the results from the multiple correction schemes is also performed and it leads to further improved 5-yr average prediction accuracy. 相似文献
997.
为解决田间调查时因信息沟通手段与渠道的制约而产生的苗情灾情报送迟滞这一瓶颈问题,基于Android手机平台,构建了一种作物苗情灾情快速上报系统。系统由服务器端和客户端两部分组成。服务器端主要负责苗情灾情数据的存储与下载,研究中采用HTTP文件服务器,可通过设置IP、端口及用户名、密码和共享路径等实现远程文件的上传与下载;客户端主要实现苗情灾情的采集与上传,研究中依托手机自带拍照、GPS定位、数据传输等功能,基于Android编程技术对系统的功能和界面进行了设计。系统主要功能包括苗情灾情固定与非固定地块的实时采集、汇总与远程服务端(云平台)传输。由于系统基于Android设备开发,有效降低了常规硬件部件的费用,最大限度地降低使用成本。经过2年多的初步测试使用表明,系统具有较好的稳定性及时效性,苗情灾情速报功能可满足市级管理人员的基本需求,可实现大面积苗情灾情数据的快速统计、实时上报,从而为获取实时农情数据和开展灾后救援工作提供可靠支撑。 相似文献
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1000.
中国北方2021年3月中旬持续性沙尘天气的特征及其成因 总被引:2,自引:2,他引:0
沙尘天气是多发于中国北方春季的灾害性天气,严重危害农业生产、交通运输、空气质量和人民的生命财产安全,长期受到社会各界的广泛关注。利用多源多尺度数据,采用天气学分析、物理量诊断、轨迹分析等方法对2021年3月中旬西北地区东部一次持续性沙尘重污染天气的成因进行了深入分析。结果表明:(1)受强烈发展的蒙古气旋影响,蒙古国南部及中国内蒙古中西部地区于3月14日首先出现强沙尘暴天气,并将沙尘传输至中国西北、华北、东北一带,西北东部的沙尘天气维持达到5 d。(2)沙尘天气维持期,西北东部中低层以弱上升运动为主,大气层结稳定,且西北东部不断有弱锋生发展,不利于沙尘的沉降;自北向南分布的银川、中卫、兰州3站的垂直螺旋度的波动与污染浓度的变化基本一致;混合层高度较其气候平均值明显偏低,不利于大气湍流发展。(3)此次影响西北东部的沙尘主要由蒙古国输入,近20年中蒙边境、蒙古国南部的植被减少可能是此次沙尘天气的沙源主要来自蒙古国南部的原因。 相似文献