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991.
With rapid development of urbanization and regional interaction and interdependence, regional urban agglomeration planning
becomes more and more important in China, in order to promote integrated development of various cities with close interrelationship.
However, it is still arguable academically on how to define the boundary or which cities to be included for the urban agglomeration
of a region. This paper aims to shed lights on how to identify urban spheres of influence scientifically by introducing field
modeling method and by practicing a case study on 168 cities in Central China. In our field modeling method, the influence
intensities of cities were measured by a comprehensive index and urban spheres of influence were represented spatially by
field intensity. Then, their classification and spatial distribution characteristics of study area in 2007 were identified
and explored by using GIS and statistical methods. The result showed that: 1) Wuhan is the absolute dominant city in Central
China; 2) the provincial capital cities dominate their own provinces and there are no other lower grade agglomeration centers;
and 3) the basic types of organization form of urban sphere of influence are single-polar type, agglomeration type, close-related
group type and loose-related group type. 相似文献
992.
Flashfloodsaretheimportanteventsofthehydrologicalregimeofriversinaridareas.IntheTarilncaver(Fig.1),northwesternChina,flashfledarebeingmonitored.TheobSerVeddataandinvestigationdemonstratethedifferenceintime,place,frequencyandintensityoftheiroccurrences.Therearethreet~offlagescommontotheThermcaverbasin.AlmOSteveryyea-rhighwateroccursinmonthesofJuly,AugUstandseptembercausedbyablationrunoff.However,themostdamagingflowSarefromoccasionalflashfindsbyinstenserainstormandglacierlakeoutburstflags(… 相似文献
993.
994.
On Franck-Condon factors and intensity distributions in some band systems of I2, NS and PS molecules
Potential curves for theB andX states of I2, NS and PS have been obtained by Rydberg-Klein-Rees (RKR) method. From these RKR potentials, Franck-Condon factors (FCFs)
lot the above band systems have been calculated using the best available molecular constants, tested for accuracy on the electronic
transition moment (ETM)-r-centroid curve in the case of I2 and used in the study of observed abnormal intensity distribution in some bands of NS. A brief outline of the method used
in the calculations of the FCFs is given. 相似文献
995.
The monthly cosmic ray intensity (CRI) time series from Climax, Huancayo, Moscow, Kiel, and Calgary are used to investigate
the presence of the 11-year periodic component with special attention paid to the solar influence on these variations. The
results show obvious 11-year temporal characteristics in CRI variations. We also find a close anticorrelation between the
11-year solar cycle and CRI variations and time delays of the CRI relative to solar activity. 相似文献
996.
利用中国气象局成都高原气象研究所在青藏高原东坡理塘地区建立的大气综合观测站观测资料, 以2006年1月和7月涡旋相关资料分别代表冬季和夏季, 分析和比较了该地区近地层包括风速、 风向、 大气稳定度在内的平均场特征, 以及湍流强度、 无量纲化风脉动方差相似性和地表通量变化特征,结果表明, 1月和7月稳定度基本集中在±0.5和±0.25之间; 湍流在<2 m·s-1的风速环境中发展最为旺盛, 随着风速的增大湍流强度减小迅速; 无量纲化三维风脉动方差符合Monin-Obukhov相似理论的“1/3”定律, 其最佳通用相似函数在稳定和不稳定条件下都可以拟合得到; 地表通量均表现出明显的日变化特征, 1月以感热为主, 潜热很小; 7月以潜热为主, 感热较小。 相似文献
997.
利用自制闪电宽带电场三维定位系统, 分析了山东地区一次雷暴过程闪电三维时空结构。结果表明, 在云内击穿放电整个时间序列中, 辐射源空间分布(对应强电场区分布)呈现明显的三极性分层电荷结构, 并分布在3个高度层次: 6~8 km为上部正电荷区, 4~6 km为中部负电荷, 2.5~4 km为下部次正电荷区。云内放电首先出现在中部负电荷区, 然后产生向上发展的负流光进入上部正电荷区传输, 形成向上发展的云闪; 随着雷暴发展, 产生向下发展的负流光进入下部次正电荷区, 形成向下发展的云闪, 且能维持到雷暴发展后期。结合雷达回波分析表明, 雷达回波的强度影响着闪电活动, 强回波区的增加会使得强电场区域增加, 但是强电场区域并不与最强回波区域对应, 除下部正电荷区的底部会有部分辐射源出现在回波强度为40~50 dBz的区域中以外, 大多数的辐射源出现在25~35 dBz的中等回波区范围内, 强回波区域中通常较少出现击穿放电。 相似文献
998.
In order to investigate whether adaptive observations can improve tropical cyclone (TC) intensity forecasts,observing system simulation experiments (OSSEs) were conducted for 20 TC cases originating in the western North Pacific during the 2010 season according to the conditional nonlinear optimal perturbation (CNOP) sensitivity,using the fifth version of the PSU/NCAR mesoscale model (MM5) and its 3DVAR assimilation system.A new intensity index was defined as the sum of the number of grid points within an allocated square centered at the corresponding forecast TC central position,that satisfy constraints associated with the Sea Level Pressure (SLP),near-surface horizontal wind speed,and accumulated convective precipitation.The higher the index value is,the more intense the TC is.The impacts of the CNOP sensitivity on the intensity forecast were then estimated.The OSSE results showed that for 15 of the 20 cases there were improvements,with reductions of forecast errors in the range of 0.12%-8.59%,which were much less than in track forecasts.The indication,therefore,is that the CNOP sensitivity has a generally positive effect on TC intensity forecasts,but only to a certain degree.We conclude that factors such as the use of a coupled model,or better initialization of the TC vortex,are more important for an accurate TC intensity forecast. 相似文献
999.
本文从大气热力—动力学方程出发,导出形式较为简单的热岛分析解,通过数值试验,讨论了城市热岛强度与影响因子(如平均风速,城市加热量,摩擦效应和大气稳定度等)之间的关系。 相似文献
1000.
利用ADCP和LISST-100仪观测悬浮物浓度的研究 总被引:3,自引:0,他引:3
利用黄河口海床基声学多普勒流速剖面仪(ADCP)的周日观测资料对悬浮物浓度进行了反演,反演过程中综合考虑了球面扩散、声学近场的非球面扩散、海水和悬浮颗粒的吸收衰减以及其他因素对回声信号的影响,结果表明在粒径保持相对稳定的情况下,利用ADCP仪回声强度反演悬浮物浓度具有较高的精度.结合现场激光粒度仪(LISST-100)测得的粒径分布信息在反演过程中考虑了粒径修正,重点讨论了观测区域粒径变化对结果的影响,结果表明粒径的剧烈变化会降低体积后向散射强度与悬浮物浓度之间的相关性.大颗粒物质的存在使计算得到的悬浮物浓度偏高,粒径修正虽然在一定程度上消除了这种影响,但线性拟合的相关性并未提高. 相似文献