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971.
Numerical modeling of wind and waves for Typhoon Betty (8710) 总被引:8,自引:3,他引:8
Numerical modeling of wind and waves for TyphoonBetty(8710)TXNumericalmodelingofwindandwavesforTyphoonBetty(8710)YuWeidong,Qia... 相似文献
972.
Investigated in this study is the flow-induced vibration of a nonlinearly restrained curved pipe conveying fluid. The nonlinear equation of motion is derived by equilibrium of forces on microelement of the system under consideration. The spatial coordinate of the system is discretized by DQM (differential quadrature method). On the basis of the boundary conditions, the dynamic equation is solved by the Newton-Raphson iteration method. The numerical solutions reveal several complex dynamic motions for the variation of the fluid velocity parameter, such as limit cycle motion, buckling and so on. The result obtained also shows that the sub parameter regions corresponding to the several motions may change with the variation of some parameters of the curved pipe. The present study supplies a new reference for investigating the nonlinear dynamic response of some other structures. 相似文献
973.
974.
975.
TheconcentrationoftotaldissolvedCO_2insurfacewaterinENSOevent──TheresultsofinvestigationduringTOGAexpeditions¥MaLiming;ZhangB?.. 相似文献
976.
Mathematical modeling conducted in this study evaluated the hydrodynamic performance of a wave-driven artificial upwelling device in ocean waves off the Hawaiian islands. The device consisted of a buoy (4.0 m in diameter) and a tail pipe (1.2 m in diameter, 300 m in length) with a flow controlling valve. Random ocean waves off the Hawaiian islands used in the device's modeling analysis were synthesized from a wave spectrum obtained from available data. For comparison, the device's performance was also evaluated in regular waves whose height and period are the same as the significant wave height and wave period of random Hawaiian waves. Modeling results indicated that an upwelling flow of 0.95 m3/sec can be generated by this device in random Hawaiian waves and an upwelling flow rate of 0.45 m3/sec can be generated in regular waves. A simple mathematical model which assumed that the device exactly follows the incident waves was used in previous studies. Analysis results also indicated that the simple model cannot satisfactorily simulate the relative velocity and acceleration of the water column in the device. Since the relative velocity and acceleration are important factors in determining the rate of upwelling flow, the simple model must be applied with caution. 相似文献
977.
Zhang Rong-Hua Yu Yongqiang Song Zhenya Ren Hong-Li Tang Youmin Qiao Fangli Wu Tongwen Gao Chuan Hu Junya Tian Feng Zhu Yuchao Chen Lin Liu Hailong Lin Pengfei Wu Fanghua Wang Lin 《中国海洋湖沼学报》2020,38(4):930-961
El Nino-Southern Oscillation(ENSO) is the strongest interannual signal that is producedby basinscale processes in the tropical Pacific,with significant effects on weather and climate worldwide.In the past,extensive and intensive international efforts have been devoted to coupled model developments for ENSO studies.A hierarchy of coupled ocean-atmo sphere models has been formulated;in terms of their complexity,they can be categorized into intermediate coupled models(ICMs),hybrid coupled models(HCMs),and fully coupled general circulation models(CGCMs).ENSO modeling has made significant progress over the past decades,reaching a stage where coupled models can now be used to successfully predict ENSO events 6 months to one year in advance.Meanwhile,ENSO exhibits great diversity and complexity as observed in nature,which still cannot be adequately captured by current state-of-the-art coupled models,presenting a challenge to ENSO modeling.We primarily reviewed the long-term efforts in ENSO modeling continually and steadily made at different institutions in China;some selected representative examples are presented here to review the current status of ENSO model developments and applications,which have been actively pursued with noticeable progress being made recently.As ENSO simulations are very sensitive to model formulations and process representations etc.,dedicated efforts have been devoted to ENSO model developments and improvements.Now,different ocean-atmosphere coupled models have been available in China,which exhibit good model performances and have already had a variety of applications to climate modeling,including the Coupled Model Intercomparison Project Phase 6(CMIP6).Nevertheless,large biases and uncertainties still exist in ENSO simulations and predictions,and there are clear rooms for their improvements,which are still an active area of researches and applications.Here,model performances of ENSO simulations are assessed in terms of advantages and disadvantages with these differently formulated coupled models,pinpointing to the areas where they need to be further improved for ENSO studies.These analyses provide valuable guidance for future improvements in ENSO simulations and predictions. 相似文献
978.
新疆东准噶尔北塔山蛇绿混杂岩锆石SHRIMP U-Pb定年、氧同位素及其地质构造意义 总被引:3,自引:1,他引:2
本文为首次报道东准噶尔北塔山蛇绿混杂岩的锆石SHRIMP U-Pb年龄及氧同位素。北塔山蛇绿混杂岩出露于扎河坝-阿尔曼泰蛇绿混杂岩东南端,中蒙边境附近。岩石地球化学表明,其主要为岛弧玄武岩,稀土元素球粒陨石标准化模式表现为轻稀土相对富集,微量元素的N-MORB标准化蛛网图显示富集大离子亲石元素(LILE),存在Nb和Ta负异常,显示了受消减带影响的信息,其可能是准噶尔地区洋壳俯冲-消减的产物。东准噶尔北塔山蛇绿混杂岩中辉长岩的锆石获得了3组SHRIMP U-Pb年龄,第一组锆石的年龄为494±3Ma(n=14,χ2=1.16),对应δ18O加权平均值为5.2±0.3‰(1σ),与幔源锆石δ18O值(5.3±0.3‰)相一致,代表了辉长岩的形成年龄,亦代表了该蛇绿岩形成时代。辉长岩中第二组锆石的SHRIMP UPb年龄范围为412±13Ma和259~264Ma,对应锆石δ18O值为6.5±0.1‰~11.1±0.1‰,表明它们受到后期高δ18O壳源流体/熔体不同程度的改造。研究区与玄武岩呈侵入接触关系的花岗斑岩锆石SHRIMP U-Pb年龄为407±2Ma,代表了该花岗斑岩的形成年龄,并约束了阿尔曼泰洋盆的闭合时限可能为晚志留纪-早泥盆纪。而其对应锆石δ18O值为6.1±0.2‰(1σ),反映了岩浆物质可能主要来源于下伏玄武质洋壳。本文的研究结果不仅表明北塔山蛇绿岩形成于晚寒武世,而且进一步证明它是扎河坝-阿尔曼泰蛇绿岩带的东南延伸。更为重要的是,本文的研究还证明锆石O同位素研究与锆石SHRIMP定年研究相结合是合理解释蛇绿岩中锆石年龄复杂性的有效途径之一。 相似文献
979.
地理信息系统中动态分段技术的研究 总被引:1,自引:0,他引:1
动态分段是一种新的线性特征的动态分析、显示和绘图技术。本文结合GIS在公路信息管理领域的应用,论述了动态分段技术产生的根源,动态分段数据库的特点及实现动态分段的算法。以空间数据库和属性数据库的双向查询为例,说明了动态分段技术的具体应用,它的有关算法及命令格式。 相似文献
980.
本文研究了基于随机分形的数字高程模型算法。实践证明,用此方法进行形状逼近内插,所需数据量小,可节省大量内存及计算时间,较容易获得所需要的分辨率。 相似文献