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91.
为准确表达用户兴趣,提升网络地图个性化服务效率,本文结合用户的操作行为与视觉行为,探讨了用户兴趣获取的原理与方法。结合Web日志与眼动数据的特点,提取网络地图的用户兴趣特征项,并利用熵权法对用户兴趣度进行估计。通过向量空间模型,构建网络地图用户兴趣模型,并开展验证实验对用户兴趣建模方法进行验证。  相似文献   
92.
本文根据地壳运动的全球通量均衡假说建立了地壳垂直形变场的分析模型,分析了以往作者所研究的球谐函数和球冠谐函数模型的优缺点,着重推导了在密切平面坐标系下该模型的Fourier级数解,该模型一方面可以简单地应用于地壳垂直形变场的逼近,另一方面为采用谱分析法提取地壳垂直形变场信息提供了理论依据。  相似文献   
93.
Origin-destination flow maps are often difficult to read due to overlapping flows. Cartographers have developed design principles in manual cartography for origin-destination flow maps to reduce overlaps and increase readability. These design principles are identified and documented using a quantitative content analysis of 97 geographic origin-destination flow maps without branching or merging flows. The effectiveness of selected design principles is verified in a user study with 215 participants. Findings show that (a) curved flows are more effective than straight flows, (b) arrows indicate direction more effectively than tapered line widths, and (c) flows between nodes are more effective than flows between areas. These findings, combined with results from user studies in graph drawing, conclude that effective and efficient origin-destination flow maps should be designed according to the following design principles: overlaps between flows are minimized; symmetric flows are preferred to asymmetric flows; longer flows are curved more than shorter or peripheral flows; acute angles between crossing flows are avoided; sharp bends in flow lines are avoided; flows do not pass under unconnected nodes; flows are radially distributed around nodes; flow direction is indicated with arrowheads; and flow width is scaled with represented quantity.  相似文献   
94.
太平洋板块俯冲对中国大陆的影响   总被引:8,自引:0,他引:8  
在中国大陆及周边地区ITRF2000速度场的基础上,建立欧亚板块整体旋转与线性应变运动模型,得到中国大陆及邻区的局部形变场,分析此形变场发现东北块体和华北块体东部地壳存在一致的向西或北西西向运动,平均运动速率东北为2.9 mm/a,华北东部为1.4 mm/a,推测这是太平洋板块向欧亚板块俯冲的影响。其影响范围仅限于东北和华北块体,影响较大的是120°E以东和40°N以北地区。并分析太平洋板块俯冲对中国大陆影响的表现形式和形成机制。  相似文献   
95.
向斜构造煤层开采地表移动规律研究   总被引:5,自引:0,他引:5  
现行的地表移动预计方法,都是建立在开采工作面主断面为线性分布的基础上,因此,对于非线性分布煤层的预计将会产生较大的误差。本文以随机介质理论为基础,利用曲线积分的方法建立了地表移动与变形预计公式,并且利用数值积分法和叠加原理解算地表移动与变形值,扩大了地表移动预计理论的应用范围,同时也大大提高了预计值的精度  相似文献   
96.
吕志平 《测绘学报》1996,25(2):146-150
本文阐述了空间大地网联合处理中的地壳运动模型的建立方法,并在此基础上提出了非均匀形变,均匀形变,体应变和刚体转动的识别方法,文中以我国现有空间大地网的模拟数据,结合中国大陆地壳构造进行了试算。  相似文献   
97.
The colloidal borescope consists of a set of lenses and miniature video cameras capable of observing natural particles in monitoring wells. Based on field observations of these particles, it appears possible to measure in situ groundwater velocity in a well bore. Field observations have shown that directional measurements using the colloidal borescope are generally in good agreement with expected flow directions. However, the magnitude of flow velocity is higher compared with values based on conventional test methods. High relative flow velocities, even after correction factors have been applied to compensate for well bore effects, are believed to be due to preferential flow zones in the surrounding aquifer. Low flow zones exhibit swirling multidirectional flow that does not allow for a linear velocity measurement. Consequently, groundwater flow velocities measured by the colloidal borescope in heterogeneous aquifers will be biased toward the maximum velocity values present in the aquifer. A series of laboratory experiments was conducted to assess the reliability of the instrument. Based on this work, a seepage velocity correction factor ( ) of 1–4 was found for quantifying groundwater seepage velocity in the adjacent aquifer from observations in a well bore. Laboratory measurements also indicate that preferential flow in the surrounding aquifer dominates flow in the well. Results of this work suggest the possibility of quantifying higher-flow velocities associated with preferential flow zones in the subsurface.  相似文献   
98.
黑龙江及邻区地壳应力场初步研究   总被引:1,自引:0,他引:1  
采用综合震源机制方法,利用5 002条P波极性数据反演黑龙江地区二维应力结构,求得该区0.5°×0.5°综合震源机制解.初步研究表明:21世纪以来,构造应力场总特征基本一致,具有明显的继承性,主压应力和主张应力的优势方向明显,与板块运动关系具有成因上的联系.  相似文献   
99.
In order to track the space-time variation of regional strain field holistically(in a large scale) and to describe the regional movement field more objectively,the paper uses a nonlinear continuous strain model focused on extracting medium-low frequency strain information on the basis of a region with no rotation.According to the repeated measurements(1999~2001~2004) from GPS monitoring stations in the Sichuan and Yunnan area obtained by the Project of "China Crust Movement Measuring Network",and with the movement of 1999~2001(stage deformation background) as the basic reference,we separated the main influencing factors of the Kunlun Mountain M-S8.1 earthquake in 2001 from the data of 2001 and 2004,and the results indicate:(1) the Kunlun Mountain M-S8.1 earthquake has a discriminating effect on the Sichuan and Yunnan area,moreover,the deformation mode and background had not only certain similitude but also some diversity;(2) The movement field before the earthquake was very ordinal,while after the earthquake,order and disorder existed simultaneously in the displacement field;The displacement quantities of GPS monitoring stations were generally several millimeters;(3) The principal strain field before earthquake was basically tensile in an approximate EW direction and compressive in the SN direction,and tension was predominant.After the earthquake,the principal strain field in the Sichuan area was compressive in the EW direction and tensile in the SN direction,and the compression was predominant.In the Yunnan area,it was tensional in the NE direction and compressive in the NW direction,and tension was predominant;(4) The surficial strain before the earthquake was dominated by superficial expansion,the contractive area being located basically in the east boundary of Sichuan and Yunnan block and its neighborhood.After the earthquake,the Sichuan area was surface contractive(the further north,the greater it was),and south of it was an area of superficial expansion.Generally speaking,the Kunlun Mountain M-S8.1 earthquake played an active role in the accumulation of energy in the Sichuan and Yunnan area.Special attention shall be focused on the segment of Xichang-Dongchuan and its neighborhood.  相似文献   
100.
Radiocarbon dating of thin palaeopodsols buried beneath turf-banked gelifluction lobes at four localities in the low alpine mountain zone in the Jostedalsbreen region, western Norway, show that gelifluction processes were initiated subsequent to the late Subboreal Chronozone. Although large age-depth gradients have been demonstrated from buried palaeosols in southern Norway, evidence is presented that the palaeosols in this study show only moderate age-depth gradients. The age estimates from these buried palaeosols give maximum dates of burial, but the error is not thought to be large. Gelifluction processes were probably initiated close to the time of the climatic deterioration, which led to the formation of the present glaciers during the Subatlantic Chronozone. The processes may have been most active during the peak of the Little Ice Age, during which a periglacial climate was established to low levels in this mountainous region.  相似文献   
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