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91.
雷坤超 《地质学报》2024,98(2):591-610
超量开采地下水引发的地面沉降已成为制约北京区域社会经济可持续发展的重要因素之一。2014年12月,南水北调中线工程正式通水,每年向北京输水超过10×108 m3,改变了北京供水格局,也为地下水压采、涵养及控制地面沉降创造了条件。本文利用多种监测数据,分析南水进京前后,北京平原区地下水和地面沉降的变化;研究不同水位变化模式下不同岩性及深度土层的变形特征;计算土层不同变形阶段的弹性和非弹性储水率;并对黏性土层产生较大残余变形和滞后变形的原因进行了探讨。结果表明:① 2015~2020年,平原区大部分地区第一至第四含水层组地下水位逐渐上升,地面沉降呈减缓的趋势。② 第二和第三压缩层组是沉降主要贡献层,除平各庄和榆垡站外,其余各站第三压缩层组沉降占比逐渐增大,沉降主控层有向深部转移的规律。③ 平原区北部和东部,第二和第三压缩层组对应的地下水位由降转升。在水位下降阶段,土层呈塑性和蠕变变形;水位上升阶段,土层以塑性变形为主,部分时间出现弹性变形,具有黏弹塑性。平原区南部,地下水位始终持续下降,土层变形始终呈塑性和蠕变变形。含水砂层则主要呈弹性变形。④ 土层变形的不同阶段,弹性和非弹性储水率并不是恒定的,随着地下水位下降,储水率呈减小的趋势。⑤ 黏性土层存在较大残余变形和变形滞后的原因,一是非弹性储水率大于弹性储水率,二是黏性土层的弱渗透性。  相似文献   
92.
总结了Motorola VP OnComm接收机的几种数据格式。采用MAX232作为计算机串口和接收机输出口之间的电平转换接口器件,在MicrosoftVisualC 6.0平台上,利用MSComm控件开发了MotorolaVP OnCoreGSP接收机的数据接收软件。最后给出了数据拉媚的实例。 利用多通道共视实现纳秒量级时间传递系统的基础性工作,对于研制该系统具有重要意义。另外,该软件通用性较强,对于各种OEM板的GPS数据接收也具有实用意义或参考价值。  相似文献   
93.
Antithetic fault linkages in a deep water fold and thrust belt   总被引:4,自引:0,他引:4  
Deep water fold and thrust belts consist of both forethrusts and backthrusts that can link along strike to form continuous folds in the overburden. The interaction of faults of opposing dip are termed ‘antithetic thrust fault linkages’ and share the common feature of a switch in vergence of overlying hangingwall anticlines. Using three-dimensional seismic data, on the toe-of-slope of the Niger Delta, linkages are classified into three distinct structural styles. This preliminary classification is based on the vertical extent of faulting within a transfer zones relative to the branch line of the antithetic faults. The stratigraphic level of the lateral tip of the fault, the shape of lateral tip region of a fault plane and the stratal deformation within the transfer zones is also distinctive in each type of fault linkage. A Type 1 linkage comprises faults that overlap exclusively above the level of the branch line. A ‘pop-up’ structure forms within the transfer zone with sediments below remaining planar. The lower tip lines of faults climb stratigraphically towards the linkage zone creating asymmetric, upward-tapering lateral tip regions. In Type 2 linkages fault overlap occurs lower than the level of the branch line such that lateral fault tips are located within the footwall of the counterpart fault. Faulting is thus limited to the deeper section within the transfer zone and creates unfaulted, symmetric, bell-shaped folds in the overburden. Upper tip lines of faults lose elevation within the transfer zone creating asymmetric, downwards-tapering lateral tip regions. In Type 3 linkages both faults continue above and below the branch line within the transfer zone resulting in cross-cutting fault relationships. Horizon continuity across the folds, through the transfer zones, varies significantly with depth and with the type of fault intersection.  相似文献   
94.
The BEAR array of simultaneous electromagnetic (EM) observations probes the deep crustal and upper mantle conductivity structure of the Baltic Shield searching for the lithosphere–asthenosphere boundary beneath. The adequate interpretation of the results of this unique high latitude natural field EM sounding requires proper understanding of the actual external excitation conditions because conventionally used plane wave model assumptions may be substantially violated in the vicinity of inhomogeneous polar sources. The paper presents an overview of the morphology and statistics of source distortions in the BEAR EM field transfer functions (TF) and the ways of their suppression. The stability of the final TF estimates obtained with the exclusion of intensive non-stationary auroral effects is further justified. The external excitation model effective for the whole BEAR observation period is inferred from the array distribution of the inter-station geomagnetic transfer functions. The model is supported by the results of polar ionosphere–magnetosphere current system studies, based on the simultaneous ground and satellite geomagnetic observations, and sets bounds for the “plane wave” approach in the BEAR data interpretation to avoid unfounded inferences on the upper mantle electrical properties. The signatures of the lithosphere–asthenospere boundary under Fennoscandia derived from the BEAR data are summarized and its resolution within the traditional plane wave interpretational paradigm is analysed assuming the presented external source pattern and estimated TF uncertainties caused by the source inhomogeneity.  相似文献   
95.
主要讲述了彩色地图扫描自动分色的必要性,分析了扫描图数据产生颜色误差的原因,讨论了在分色过程中色彩空间转换的问题,最后得到了分色结果并对结果进行了探讨。  相似文献   
96.
The central route of the South–North Water Transfer Project (CTP) is designed to divert approximately 9.5 billion m3 of water per year from the Han River, a major tributary of the Yangtze River, to the Hai River basin in the north China. The main purpose of this study is to assess the impact of CTP on groundwater table in the Hai River basin. Our study features a large‐scale distributed hydrological model that couples a physically based groundwater module, which is sub‐basin‐based, with a conceptual surface water module, which is grid‐based. There are several grids in each sub‐basin and water exchange among grid that are considered. Our model couples surface water module and groundwater module and calculates human water use at the same time. The simulation results indicate that even with the water supply by CTP, the groundwater table will continue to decline in the Hai River basin. However, the CTP water can evidently reduce the decline rate, helping alleviate groundwater overexploitation in Hai River region. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   
97.
Land use classification requires a significant amount of labeled data, which may be difficult and time consuming to obtain. On the other hand, without a sufficient number of training samples, conventional classifiers are unable to produce satisfactory classification results. This paper aims to overcome this issue by proposing a new model, TrCbrBoost, which uses old domain data to successfully train a classifier for mapping the land use types of target domain when new labeled data are unavailable. TrCbrBoost adopts a fuzzy CBR (Case Based Reasoning) model to estimate the land use probabilities for the target (new) domain, which are subsequently used to estimate the classifier performance. Source (old) domain samples are used to train the classifiers of a revised TrAdaBoost algorithm in which the weight of each sample is adjusted according to the classifier’s performance. This method is tested using time-series SPOT images for land use classification. Our experimental results indicate that TrCbrBoost is more effective than traditional classification models, provided that sufficient amount of old domain data is available. Under these conditions, the proposed method is 9.19% more accurate.  相似文献   
98.
在轨道交通网建设初期,交通换乘设施与产业的布局直接关系到各站点的运营与使用效率,选择合理的评价方式,在空间上正确评判其供需水平,能为进一步的规划设计提供科学依据。本文以杭州轨道交通一号线为例,通过空间句法模型,为已投入运营的31个站点的空间整合度进行定量化分析研究:在轨道交通站点可达性评价的基础上,应用GIS—AHP方法,整合现状资料,得出轨道交通需求空间分布特征:结合现状调研资料,阐述空间整合度与交通需求相互作用的机制,进一步讨论杭州轨道交通一号线换乘设施布置的策略,对其未来发展提出建议。  相似文献   
99.
本文结合国土资源部数据中心现状,分析研究了实现同城灾备的技术方案,即同步传输方案和异步传输方案,以及这些技术方案的技术实现层面:存储层、主机层和数据库层。在此基础上,本文进一步分析了两种方案的技术框架、设备组成和技术特点,并对两种方案在数据安全保障、对生产系统影响、传输距离和带宽要求和应用场景等方面进行了对比,为今后同城灾备中心建设提供了思路。  相似文献   
100.
在综合考虑系统功能需求、数据交换和共享、未来系统扩展、建设成本等多种因素的基础上,采用C/S与B/S相结合的模式,从系统体系结构、系统功能、数据库结构、系统运行环境、用户界面等方面对南水北调环境监测管理系统进行设计。  相似文献   
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