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951.
952.
Understanding of saline intrusion into coastal aquifer is an important issue in management and protection of groundwater resource,
which can be well achieved by groundwater modelling. To explain some phenomena of correlation between groundwater level and
salinity in observation wells in coastal area, the authors compare the migration velocity of saline particles and transmission
velocity of water pressure and derive analytical equations of these two velocities for plane and radial flows. The driving
force and resistance of saline intrusion were analysed based on the analytical modelling. The destruction and reconstruction
of the equilibrium between fresh water seepage towards sea and saline dispersion to inland were considered as an essence of
whole intrusion process. The dynamic process of seepage and dispersion at different stages of saline intrusion were analysed
under groundwater over-exploitation. The basic equations of saline intrusion were derived and the mechanism of transitional
zone movement was discussed. These constitute coupled seepage–dispersion theory of saline intrusion, which becomes an important
supplement to existing theory of saline intrusion. As a case study on saline intrusion in Guangrao County in Eastern China,
this theory was applied to predict the development of saline intrusion in the study area. 相似文献
953.
954.
层状粘弹性介质中SH波的反射、透射问题 总被引:1,自引:0,他引:1
处理粘弹性介质有两种方法,一种是在运动方程中加入介质的粘滞性因素,另一种是从本构方程入手,建立介质的粘弹性模型。后一种方法在研究介质物理性质上具有直接性,是目前使用较为普遍的处理方法。从本构方程的角度,以波尔兹曼(Bo ltzm ann)叠加原理为基础,建立积分型本构方程,进而建立粘弹性介质波动方程,得到二维粘弹性平面波解,并研究了层状粘弹性介质分界面处平面波的反射、透射问题,计算反射、透射系数CR、CT,同时进行了一定的理论分析。 相似文献
955.
利用中值滤波技术能够很好的抑制噪声和保护边缘信息这一特性,用不同的滤波窗口对遥感图像进行处理,并做出处理后图像的归一化差值图像。通过图形分析发现差值图像上的信息比原始图像细节信息更丰富,某些地质现象更清晰。 相似文献
956.
通过胡杨树轮宽度的分析,建立了内蒙古额济纳地区过去233年来的STD,RES和ARS年表;并将树轮STD年表与采样点附近额济纳气象站的气温、降雨量以及狼心山水文站的地下水水位等记录进行了相关分析。结果表明,在额济纳地区显著影响该地胡杨生长的主要限制因子是地下水水位。胡杨树轮宽度年表与冬季及全年地下水水位相关性最高,分别为-0.808(p<0.01)和-0.724(p<0.05)。在此基础上,设计转换方程,重建了额济纳地区过去232年来冬季及全年地下水水位变化历史,冬季地下水水位重建方程的解释方差达76.3 % (调整自由度后为70.4 % ,n=11,r=0.874,F=12.881,p<0.003),全年地下水水位重建方程的解释方差为72.8 % (调整自由度后为66.1 % ,n=11, r=0.854,F=10.731,p<0.005)。 相似文献
957.
Torsional response of pile embedded in a poroelastic medium 总被引:1,自引:0,他引:1
Yuanqiang Cai Gang Chen Changjie Xu Dazhi Wu 《Soil Dynamics and Earthquake Engineering》2006,26(12):1143-1148
The response of a cylindrical elastic pile embedded in a homogeneous poroelastic medium and subjected to torsional loading is studied for the first time. Based on the Muki's model, the pile-porous medium system is decomposed into a fictitious pile system and an extended porous medium system. The one-dimensional, vertical, elastic pile and the three-dimensional poroelastic medium are solved, respectively. Considering the mixed boundary-value conditions at the interface of pile and soil, a Fredholm's integral equation of the second kind for the bar-force is established. The force and the displacement of the pile are calculated by applying numerical quadrature. 相似文献
958.
The Contemporary Tectonic Strain Rate Field of Continental China Predicted from GPS Measurements and its Geodynamic Implications 总被引:7,自引:0,他引:7
In Appling studies, the strain rate in China has been computed from using different methods, resulting in quite different
estimates of the strain rate the geo-statistics from GPS velocity field of Chinese continent, we obtain the velocity value
at each little regularly spaced grid point, by kriging interpolation and the component of strain rate for each volume element,
using a method similar to the derivation of shape functions in the finite element algorithm. Therefore the distribution of
the strain rate field in whole for the Chinese continent is presented. The result shows that the orientations of principal
strain rates are consistent with those of the P and T axes of focal mechanisms. The distribution of maximum shear strain rate
clearly delineates some major active fault zones surrounding the Tibetan Plateau. The maximum shear strain rate is comparable
with that obtained from analysis of seismic moment release. In part of the Tibetan Plateau containing normal faults and pull-apart
grabens, we obtain an extensional state of strain. The absolute value of the strain rate in West China is approximately 5
times larger than that of East China, and the pattern of the strain rate field in most of the Chinese continent is controlled
by the India/Eurasia collision. 相似文献
959.
大庆长垣反转构造样式及其识别方法 总被引:2,自引:0,他引:2
ZHAO Bin LIU Cai WANG Shi-yu LI Peng LIU Yang FENG Xuan College of GeoExploration Science Technology Jilin University Changchun China 《吉林大学学报(地球科学版)》2006,(Z2)
大庆长垣位于松辽盆地中部坳陷区,其内部的反转构造主要分为断层控制型和非断层控制型。探讨了伸展构造体系中反转构造的识别方法,同时分析了反转构造与油气聚集的关系,对今后找寻油气藏具有指导意义。 相似文献
960.