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901.
1999年6月,29个国家科学部长作出建立全球生物多样性信息中心(GBIF)的决定,Sloan基金会和美国全国海洋合作伙伴计划(ZOPP)希望参加此中心海洋部分的工作,建设海洋生物地理信息系统(OBIS)。据系统设计者设想,在若干年内,任何人从世界地图上都能获得任何海区  相似文献   
902.
于1991年9月在青岛市沙子口镇对虾养殖场采集中国对虾病虾,采用酒石酸钾-甘油密度梯度离心法从病虾肝胰腺中分离出一种呼肠孤科病毒,并通过电子显微镜观察和提取分析病毒基因组核酸等方法初步鉴定,结果显示,该病毒在酒石酸钾-甘油密度梯度离心纯化时与肝胰腺细小病毒混合存在,病毒颗粒为有包膜的正二十面体立体对称结构;带包膜的完整颗粒直径在64-66nm;裸露核衣壳平均直径为53.2nm,病毒基因组由分成10  相似文献   
903.
904.
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   
905.
波向对变风向的响应   总被引:1,自引:0,他引:1  
由能量平衡方程导出匀质波场局地风生浪平均波向对变风向的响应。结果表明,响应的时间尺度不但取决于波能的成长速率,还取决于方向分布函数和风向与平均波向之夹角。按文圣常提出的在局地风作用下的标准风浪成长曲线,对其响应时间尺度的定量估计结果表明,本文提出的无因次响应时间尺度与无因次能量和无固次峰频率的关系,与现已提出的模式比较与实测更符合。  相似文献   
906.
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   
907.
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   
908.
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   
909.
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   
910.
RY-3溶氧仪测试结果分析   总被引:1,自引:0,他引:1  
给出了作者研制的RY-3溶解氧测试仪的银极电位与美国 YSI-58溶氧仪 的银极电位(在海水中均以甘汞电极为参比电极)对比测试的误差分析,对RY-3溶 氧仪与YSI-58溶氧仪现场对比测试的结果进行误差分析。并介绍了国家标准物质 研究中心和青岛计量测试所对RY-3溶氧仪的测试结果。  相似文献   
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