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531.
Mohammadreza Moharrami Ioannis Koutromanos Marios Panagiotou Sadik Can Girgin 《地震工程与结构动力学》2015,44(5):677-694
This paper uses nonlinear truss models for the analysis of shear‐dominated reinforced concrete (RC) columns subjected to cyclic loading. A previously established method, aimed to the analysis of RC walls, is enhanced to allow simulations of column members. The concrete constitutive equations are modified to account for the contribution of the aggregate interlock to the shear resistance. Additionally, an equation is proposed to determine the inclination angle of the diagonal members in the truss models. The modeling approach is validated using the results of quasi‐static and dynamic tests on shear‐dominated RC columns. The combination of predictive capabilities and conceptual simplicity establishes truss‐based models as an attractive approach for the systematic analysis of shear‐dominated RC frame construction. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
532.
Oya Pamukçu Tolga Gönenç Osman Uyanik Hasan Sözbilir Olcay Çakmak 《Acta Geophysica》2014,62(4):849-871
Western Anatolia has an extensional tectonic regime and the characteristics of the deformation in the continental crust observed in Aegean Region have a very complex structure. In our study area, the ?zmir city, Turkey, which is located within this active region, the general geological setting is also rather complex. This first microgravity study in ?zmir and its surroundings is related to the determination of active fault zones. It was conducted in the south of ?zmir, with the aim to investigate this complex structure in detail through microgravity data collected from six profiles throughout the survey area. The variation in Bouguer values was profoundly investigated along Profile P1 in N-S direction that was delineated to intersect all the tectonic elements. For this reason, Profile P1 was modeled in this study as 2D. As a result, the created gravity model was investigated together with geology, earthquake focal depths, and isostasy. 相似文献
533.
随着人口的激增和水资源压力的不断增大,跨界含水层在地下水利用和供水安全保障方面处于越来越重要的位置。目前,围绕跨界含水层主要开展了以下三个方面的工作:联合国教科文组织国际水文计划联合其他相关机构,对世界各主要大洲进行了跨界含水层的标示及划分工作;在总结完善相关跨界含水层法律条文的基础上,联合国国际法委员会于2008年向联合国大会上提交了跨界含水层草案条款,该项草案条款的出台对共享含水层各国开发和管理地下水具有重要的指导意义;在联合国教科文组织及其他机构的推动下,各大洲已逐步开展对跨界含水层的研究,并建立了相关的合作机构。分析表明,跨界含水层的研究需要相关国家间的进一步协商与合作。 相似文献
534.
Can Zulfikar Mustafa Erdik Erdal Safak Hikmet Biyikoglu Cagatay Kariptas 《Bulletin of Earthquake Engineering》2016,14(9):2565-2578
This paper describes a rapid response and risk mitigation system Istanbul Natural Gas Distribution Network Seismic Risk Reduction Project (IGRAS) for the Istanbul Natural Gas Network (IGDA?). Upon the trigger signal received from the earthquake early warning system in Istanbul, the real-time algorithm at IGRAS system district regulators checks the threshold levels of ground-motion parameters and interrupts the gas flow if any exceedance is detected. Then the system: (1) produces almost real-time earthquake hazard maps by using on-line strong-motion data from the strong-motion network in Istanbul: (2) estimates the distribution of damage to the natural gas network; and (3) transfers these damage distribution maps to stakeholders to enable dispatching rapid response teams to high damage areas. 相似文献
535.
隧道围岩中的结构面将岩体切割成块体,块体在自然状态下的静力平衡因为隧道开挖而被打破,临空面的产生和动荷载的施加都可能导致块体的滑移,进而引起围岩失稳。以往应用块体理论寻找关键块体时,多只考虑纯重力的作用,而忽视了爆破振动、地震等动荷载对诱发失稳灾害的重要作用。将爆破振动荷载和地震荷载转化为等效静力,并通过数学计算求出使块体安全系数最低的动荷载方向,再利用关键块体理论矢量分析方法分析隧道围岩的稳定性。在长岗隧道中的应用表明,考虑动荷载作用下的块体安全系数明显小于只考虑重力作用时的安全系数,原本稳定的块体也可能在动荷载作用下变成关键块体导致围岩失稳,这与长岗隧道现场记录的破坏现象相符。 相似文献
536.
Marine litter prediction by artificial intelligence 总被引:1,自引:0,他引:1
Artificial intelligence techniques of neural network and fuzzy systems were applied as alternative methods to determine beach litter grading, based on litter surveys of the Antalya coastline (the Turkish Riviera). Litter measurements were categorized and assessed by artificial intelligence techniques, which lead to a new litter categorization system. The constructed neural network satisfactorily predicted the grading of the Antalya beaches and litter categories based on the number of litter items in the general litter category. It has been concluded that, neural networks could be used for high-speed predictions of litter items and beach grading, when the characteristics of the main litter category was determined by field studies. This can save on field effort when fast and reliable estimations of litter categories are required for management or research studies of beaches--especially those concerned with health and safety, and it has economic implications. The main advantages in using fuzzy systems are that they consider linguistic adjectival definitions, e.g. many/few, etc. As a result, additional information inherent in linguistic comments/refinements and judgments made during field studies can be incorporated in grading systems. 相似文献
537.
538.
539.
A geohazard reconnaissance study based on geoscientific information for development needs of the western region of Istanbul (Turkey) 总被引:1,自引:0,他引:1
Tamer Y. Duman Tolga Can Reşat Ulusay Mustafa Keçer Omer Emre Serafettin Ateş Ibrahim Gedik 《Environmental Geology》2005,48(7):871-888
The role of geoenvironmental information is becoming increasingly important as legislative changes have forced developers
and planning authorities to consider more implications and impact on the environment of large-scale development initiatives.
Therefore, integration of surface and subsurface geoscientific information for development needs has prime importance and
provides a means of identifying potential problems and opportunities at an early stage in any planned development. However,
from the experience of recent natural disasters, it is evident that this was not case the taken into consideration in many
countries. In addition to thousands of casualties, many urbanized areas, industrial districts and large-scale engineering
structures suffered severe damages from the natural hazards due to many reasons including the lack of preliminary engineering
geological maps and zoning maps of the settlement areas. Turkey is one of the countries which is exposed to natural hazards
such as earthquakes, landslides and floods. In particular, the devastating 1999 Kocaeli earthquake, which affected the Marmara
Region of Turkey, focused the attention on densely urbanized and industrialized metropolitan areas such as Istanbul. The rapid
growth of Istanbul, particularly towards west with minimal geoscientific information resulted in an overwhelming pressure
on the natural environment. In addition, a large earthquake, which is expected to occur in the Marmara Sea within the next
30 years, also pose a threat to the city and its surroundings. In this study, on the basis of the geological, geomorphological
and geophysical reconnaissance study, an integrated geoscientific data were collected from the western region of Istanbul
and evaluated for geohazards. The paper focuses on the geological and geomorphological aspects that control the occurrence
of some geohazards such as earthquake-induced liquefaction, landslides and flooding. In this context, the geological map of
the region was revised and Quaternary deposits were classified into 11 units, in detail. Liquefaction-prone areas were evaluated
by using geomorphological criteria based on field investigation, by the examination of the available records from 88 boreholes
drilled on recent deposits and by the data from resistivity profiles. The landslides within the region were classified according
to their type, relative depth and activity. In addition, fluvial and marine flood-prone areas were also delimited within the
region. Finally, a series of maps such as landslide inventory maps, and maps showing liquefaction- and flood-prone areas were
produced with the aid of Geographic Information Systems (GIS) to assist in designing further detailed site investigations
and to reduce costs by ensuring a more focused approach to strategic planning and site selection. 相似文献
540.