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231.
A numerical model, called CCPF1 (C onsolidation with C ompressible P ore F luid 1 ), is presented for one‐dimensional large strain consolidation of a saturated porous medium with compressible pore fluid. The algorithm includes all the capabilities of a previous large strain consolidation code, CS2, written for incompressible pore fluid. In addition, fluid density and fluid viscosity are functions of fluid pressure in CCPF1. Generalization of the numerical approach to accommodate these functions requires several modifications to the CS2 method, including phase relationships, intrinsic permeability, pore pressure, fluid potential, and mass flux. Inertial forces are neglected and isothermal conditions are assumed. The development of CCPF1 is first presented, followed by an example that illustrates the effects of pore fluid compressibility on the mechanics of consolidation of saturated porous media. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
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我国新型自主研发的风云三号卫星MERSI(FY-3/MERSI)数据目前多见于试验研究,国家卫星气象中心(NSMC)发布的业务产品中尚缺乏地表温度(land surface temperature,LST)产品.为此,在分析FY-3/MERSI L1级数据HDF5格式及通道特点的基础上,采用Jiménez-Mu(n)oz和Sobrino普适性单通道地表温度反演算法,借助MATLAB编程,实现了直接利用MERSI数据进行250 m空间分辨率的LST反演与专题制图.详细介绍了LST反演算法的参数化流程,包括辐射定标、云检测处理以及地表比辐射率和大气水汽含量的估计等,并在反演LST的基础上,计算其他衍生指标,建立了FY-3/MERSI数据反演LST及制图流程.对上海市空间热环境监测分析的实验结果表明:该方法能根据设定范围对FY-3/MERSI L1数据进行快速、实时和自动处理,适用于业务化产品制作与共享,节省人力资源;形式丰富的MERSI专题制图产品可更直观、精细地揭示出上海城市热场空间格局与热岛效应特征. 相似文献
234.
结合对手机气象短信数据库及自动站数据库维护的实际工作经验,总结出利用数据库存储过程、数据库作业等,通过网络实现数据库资料的自动异地备份方法,并详细介绍了编写存储过程的语法要点及数据库作业调度的具体实现。 相似文献
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High-accuracy large-eddy simulations of neutral atmospheric surface-layer flow over a gapped plant canopy strip have been
performed. Subgrid-scale (SGS) motions are parameterized by the Sagaut mixed length SGS model, with a modification to compute
the SGS characteristic length self-adaptively. Shaw’s plant canopy model, taking the vertical variation of leaf area density
into account, is applied to study the response of the atmospheric surface layer to the gapped dense forest strip. Differences
in the region far away from the gap and in the middle of the gap are investigated, according to the instantaneous velocity
magnitude, the zero-plane displacement, the potential temperature and the streamlines. The large-scale vortex structure, in
the form of a roll vortex, is revealed in the region far away from the gap. The nonuniform spatial distribution of plants
appears to cause the formation of the coherent structure. The roll vortex starts in the wake of the canopy, and results in
strong fluctuations throughout the entire canopy region. Wind sweeps and ejections in the plant canopy are also attributed
to the large vortex structure. 相似文献
238.
6种数值模式在安徽区域天气预报中的检验 总被引:4,自引:2,他引:2
本文检验了从2006年6月到2008年12月,Grapes、MM5、WRF、T213、JMA和Germany共6个模式对安徽区域72 h内降水量、风速和气温的预报。降水量TS评分显示,从小雨到大雨,JMA的参考价值较高,从大雨到大暴雨则是MM5和WRF比较好;Germany和T213的评分均处于中间水平,而Grapes评分最低。冬夏季各模式的预报较好,其他季节预报较差。风速,24 h JMA和T213的预报较好,48、72 h MM5和WRF的参考价值较高。气温,24、48 h MM5和WRF预报较好,而72 h则是MM5和T213好。Grapes对风速和气温的预报相对较差。上述检验结果不仅有助于预报员更好地利用数值模式制作天气预报,而且为数值天气预报的解释应用提供科学依据。 相似文献
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Maria D. Kazachenko Richard C. Canfield Dana W. Longcope Jiong Qiu 《Solar physics》2012,277(1):165-183
In order to better understand the solar genesis of interplanetary magnetic clouds (MCs), we model the magnetic and topological
properties of four large eruptive solar flares and relate them to observations. We use the three-dimensional Minimum Current Corona model (Longcope, 1996, Solar Phys.
169, 91) and observations of pre-flare photospheric magnetic field and flare ribbons to derive values of reconnected magnetic
flux, flare energy, flux rope helicity, and orientation of the flux-rope poloidal field. We compare model predictions of those
quantities to flare and MC observations, and within the estimated uncertainties of the methods used find the following: The
predicted model reconnection fluxes are equal to or lower than the reconnection fluxes inferred from the observed ribbon motions.
Both observed and model reconnection fluxes match the MC poloidal fluxes. The predicted flux-rope helicities match the MC
helicities. The predicted free energies lie between the observed energies and the estimated total flare luminosities. The
direction of the leading edge of the MC’s poloidal field is aligned with the poloidal field of the flux rope in the AR rather
than the global dipole field. These findings compel us to believe that magnetic clouds associated with these four solar flares
are formed by low-corona magnetic reconnection during the eruption, rather than eruption of pre-existing structures in the
corona or formation in the upper corona with participation of the global magnetic field. We also note that since all four
flares occurred in active regions without significant pre-flare flux emergence and cancelation, the energy and helicity that
we find are stored by shearing and rotating motions, which are sufficient to account for the observed radiative flare energy
and MC helicity. 相似文献