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151.
“5.12”汶川大地震发生后,对抗震救灾“生命线”——茂县至北川公路禹里乡至擂鼓镇公路沿线进行了路基、桥梁震害和次生地质灾害应急调查,浅析震害形成机制并制定抢通方案。 相似文献
152.
An assessment of the susceptibility to rock slope failure by means of a back-propagation network is proposed for the eastern
portion of the Southern Cross-Island Highway in Taiwan. The model was developed on the basis of six influence parameters of
rock slope instability, which include the rock type, slope aspect, slope angle, joint set number, joint spacing and bedding–slope
relationship. The values of these influence parameters were used as inputs for the network and were classified as nominal
scales in terms of binary numbers, while the state of failure/non-failure of a given slope was assumed to be the output variable.
Data on a total of 170 slopes along the highway was fed into the network for learning. According to the outputs of the network,
the susceptibility to rock slope failure is categorized into four levels, namely low, medium–low, medium and high, which are
mapped along the highway. Three highly susceptible regions are found, which can be viewed as hazardous sections requiring
cautionary measures. Moreover, the proposed model can be used as a tool for determining the possible state of an unfamiliar
rock slope in the context of devising management strategies to be applied to the investigated portion of the highway. 相似文献
153.
文章在系统分析107国道935~937km段塌岸特征的基础上,应用塌岸最终趋势常规预测方法,考虑河水径流作用,从宏观上对107国道935~937km内平直河段、弯曲河段岸坡塌岸的最终趋势进行预测。并针对不同河段提出了相应的防治对策和措施。这对于土质岸河流的塌岸灾害预测和防治具有一定的指导意义。 相似文献
154.
咸水灌溉下塔里木沙漠公路防护林盐分平衡及盐分运移 总被引:5,自引:0,他引:5
应用生态系统物流理论,把土壤-植物-大气作为一个完整的系统,将植物、土壤和地下水作为三个分室,建立分室流动模型,对植物和土壤间的盐分平衡进行定量研究,探索咸水灌溉条件下塔里木沙漠公路防护林盐分运动的规律。结果表明:塔里木沙漠公路防护林使用大量咸水灌溉后盐分并没有在根层土壤0~2 m土层中累积,而是储藏在2 m以下或渗漏到地下水。其中,0~2 m土体盐储量减少125.1 t,地下水位1.50 m以上至2 m土体盐储量增加79.9 t,45.2 t盐分重新回到地下水。根层土壤0~2m土层中土壤脱盐明显。灌溉后各土层的全盐量在0.5~0.9 g/kg之间,远低于土壤原始全盐量1.47 g/kg。这是咸水灌溉下植物能够正常生长的主要原因。研究对于确定塔里木沙漠公路防护林合理的灌溉制度及预测和评估该地区盐渍化的发生发展具有重要意义。同时,也为塔里木沙漠公路全线绿化和水分管理提供科学依据。 相似文献
155.
Abstract Damage, destruction and casualties related to landslide and debris flow are common phenomena in the Himalaya, especially during the summer monsoon. This fact was tragically illustrated on 22 July 1996, when Larcha, situated at the 109-km mark of the Arniko Highway, upper Bhotekoshi Valley, central Nepal, experienced a catastrophic debris flow powered by the Bhairab Kunda Stream. Of the 22 houses in Larcha, 16 were swept away, two were partially damaged and 54 people were killed in a matter of a few minutes. The event attracted attention when media linked it to a glacial lake outburst flood as a result of the fact that the source of the stream is a glacial lake. To understand the cause, initiation mechanism and deposition process, the basin area was studied from geological, geomorphologic and engineering geological points of view and the role of precipitation was evaluated. A combination of rainfall, runoff from cliff faces and stream undercutting triggered failure of the bedrock and colluvium, both on the dip and counter-dip slopes, 500 m upstream from the highway. The landslide debris dammed the channel, which was eventually breached, and deposited approximately 104 000 m3 of coarse debris, dominated by the metasediments of the Lesser Himalayan origin, and overwhelmed the village of Larcha. The debris deposit was studied for clast size, composition, texture and dimensions. Lack of sorting and the presence of abundant silt and clay in the source area helped in the initiation of debris flow. The abundance of the Lesser Himalayan metasediment clasts together with the absence of debris traces upstream from the landslide site ruled out the possibility of a glacial lake outburst flood. The disaster was a result of landslide damming triggered by precipitation and stream undercutting and sudden bursting. 相似文献
156.
本工程为北京市京承高速公路(三环路至四环路段)工程,南起北京东北三环路太阳宫桥,向北经土城北路及规划中的曹慧路,止于北京市东北四环路望和桥,全长约为2km。本文详细介绍了该道路工程的施工测量放线过程,以及施工测量中一些常用的校核方法 相似文献
157.
158.
Distribution of landslides adjacent to the northern side of the Yarlu Tsangpo Grand Canyon in Tibet, China 总被引:2,自引:0,他引:2
This paper presents results of recent studies on distribution and category of landslides in one section of the Sichuan–Tibet
Highway, adjacent to the northern side of the Yarlu Tsangpo Grand Canyon, Tibet, Southwestern China. In the tectonic setting
predominated by compression and strike-slipping, active faults are dominant and result in the genesis of the great alpine
relief together with fluvial incision and unloading. In this section, with a distance of about 290 km between Ranwu and Lulang,
34 landslides occurred. Among them, the 12 large and super-large landslides comprise the most dangerous part of the highway
system to road users over the past 50 years. The landslides usually occurred in slopes comprised of moraine with a large thickness,
fluvio-pluvial and lacustrine deposits and fractured rocks. Based on the examination of the physical geography, structural
geology, Quaternary geology, stratigraphy and petrography, this paper presents the temporal-spatial distribution of landslides
along the section and classification of them into three types with respect to mechanism and composites of landslides.
Each of the three types is presented by distinctive case examples. Type 1 is Yigong Landslide; type 2 includes Dongjiu Landslide
group, 102 Landslide group, Suotong Landslide group, Songzong Landslide; and the type 3 is Layue Landslide. A binary landslide,
which is seldom seen in nature and which occurred in the outlet of one creek under the integrative function of fluvial incision
and road cut, is also presented. These are distributed in different parts of the area with characterized structural geology,
topography and composites (gneiss and Quaternary deposits) with accumulative quantity between Suotong and Dongjiu. The most
occurred with frequent and rapid translation, shallow shearing planes, various influential factors and unique triggering factors,
and a variable period of reoccurrence with a tendency of increasing magnitude. In this region, six influential factors greatly
contribute to their occurrence: (a) intensive neotectonic movements, (b) ongoing alpine canyon relief, (c) earthquakes, (d)
heavy precipitation, (e) stream erosion, and (f) human activities, to a certain extent. Mostly, the latter four factors play
major roles in triggering landslide occurrence. The earthquake causes the rock and soil to fracture and deform, and tends
to be unstable, or cause earth-induced landslides. The heavy rainfall in monsoon seasons which saturates the soil and lower
the shearing strength is mostly responsible for the occurrence of landslides. The stream erosion disturbs slope toes causing
progressive failure. Road construction and deforestation decrease the natural slope stability. Comments and suggestions on
the physical measures for remediation of landslides and safety of highways are also made. 相似文献
Type 1. | Landslide initiated at high elevation and transformed into a distal debris flow damming the river with a long reoccurrence interval |
Type 2. | Landslide at stream banks, in different ranks of mass movements in dissecting layers of moraines |
Type 3. | Landslide of fractured rock mass with quick translation movements. |
159.
介绍了汾灌高速公路沿线第四系和基岩的工程地质特征以及软土的防治措施,并指出球状风化体对工程地质勘察及桥基施工的影响。 相似文献
160.