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41.
42.
掌握天然气水合物储层基础物性演化特征对提升天然气水合物资源勘查与试采综合实力具有重要意义。目前,天然气水合物储层基础物性模拟实验和测试仍然以人工制备的天然气水合物岩心样品为主,导致测试结果和模拟实验认识与天然气水合物资源勘查试采工程需求仍有一定的差距,亟需原位准原位物性测试数据进行对比校正。天然气水合物储层保压取心及其后续岩心保压转移与测试是积累准原位物性测试数据的有力手段。聚焦天然气水合物储层保压取心之后的岩心保压转移与测试,全面综述了国内外现有的天然气水合物储层岩心保压转移与测试系统的优缺点,深入分析了天然气水合物储层岩心保压转移与测试获得的基础性认识;综述国内天然气水合物储层保压取心系统研发现状,梳理与之配套的岩心保压转移与测试系统研发现状及其面临的挑战;针对面临的挑战,为发展中国海域天然气水合物储层保压转移与测试技术装备研发自主能力提出了建议。 相似文献
43.
Many observations and studies indicate that pore fluid pressure in the crustal rocks plays an important role in deformation, faulting, and earthquake processes. Conventional models of pore pressure effects often assume isotropic porous rocks and yield the nondeviatoric pressure effects which seem insufficient to explain diverse phenomena related to pore pressure variation, such as fluid-extraction induced seismicity and crustal weak faults. We derive the anisotropic effective stress law especially for transversely-isotropic and orthotropic rocks, and propose that the deviatoric effects of pore fluid pressure in anisotropic rocks not only affect rock effective strength but also cause variation of shear stresses. Such shear stress variations induced by either pore pressure buildup or pore pressure decline may lead to faulting instability and trigger earthquakes, and provide mechanisms for the failure of crustal weak faults with low level of shear stresses. We believe that the deviatoric effects of pore fluid pressure in anisotropic rocks are of wide application in studies of earthquake precursors and aftershocks, oil and gas reservoir characterization, enhanced oil recovery, and hydraulic fracturing. 相似文献
44.
The experimental studies on electrical con-ductivities and P-wave velocities of anortho-site at high pressure and high temperature 总被引:1,自引:0,他引:1
Introduction The measurements of the compressional wave velocity and electrical conductivity of minerals and rocks are of fundamental importance to look into the earths interior, including composition, geotherm, generation and distribution of fluids and melts. Hydrous minerals formed by metamatu-siom are abundant within the earth. Previous studies have been carried out on the dehydration effect on the electrical conductivity and wave velocity of rocks such as serpentine, amphibole, most of whi… 相似文献
45.
David Hernández-Uribe Robert M. Holder Juan D. Hernández-Montenegro 《Journal of Metamorphic Geology》2024,42(1):89-108
Eclogite thermobarometry is crucial for constraining the depths and temperatures to which oceanic and continental crust subduct. However, obtaining the pressure and temperature (P–T) conditions of eclogites is complex as they commonly display high-variance mineral assemblages, and the mineral compositions only vary slightly with P–T. In this contribution, we present a comparison between two independent and commonly used thermobarometric approaches for eclogites: conventional thermobarometry and forward phase-equilibrium modelling. We assess how consistent the thermobarometric calculations are using the garnet–clinopyroxene–phengite barometer and garnet–clinopyroxene thermometer with predictions from forward modelling (i.e. comparing the relative differences between approaches). Our results show that the overall mismatch in methods is typically ±0.2–0.3 GPa and ±29–42°C although differences as large as 80°C and 0.7 GPa are possible for a few narrow ranges of P–T conditions in the forward models. Such mismatch is interpreted as the relative differences among methods, and not as absolute uncertainties or accuracies for either method. For most of the investigated P–T conditions, the relatively minor differences between methods means that the choice in thermobarometric method itself is less important for geological interpretation than careful sample characterization and petrographic interpretation for deriving P–T from eclogites. Although thermobarometry is known to be sensitive to the assumed XFe3+ of a rock (or mineral), the relative differences between methods are not particularly sensitive to the choice of bulk-rock XFe3+, except at high temperatures (>650°C, amphibole absent) and for very large differences in assumed XFe3+ (0–0.5). We find that the most important difference between approaches is the activity–composition (a–x) relations, as opposed to the end-member thermodynamic data or other aspects of experimental calibration. When equivalent a–x relations are used in the conventional barometer, P calculations are nearly identical to phase-equilibrium models (ΔP < 0.1). To further assess the implications of these results for real rocks, we also evaluate common mathematical optimizations of reaction constants used for obtaining the maximum P–T with conventional thermobarometric approaches (e.g. using the highest aGrs2 × aPrp in garnet and Si content in phengite, and the lowest aDi in clinopyroxene). These approaches should be used with caution, because they may not represent the compositions of equilibrium mineral assemblages at eclogite facies conditions and therefore systematically bias P–T calculations. Assuming method accuracy, geological meaningful Pmax at a typical eclogite facies temperature of ~660°C will be obtained by using the greatest aDi, aCel, and aPrp and lowest aGrs and aMs; garnet and clinopyroxene with the lowest Fe2+/Mg ratios may yield geological meaningful Tmax at a typical eclogite facies pressure of 2.5 GPa. 相似文献
46.
我国干热岩资源分布及勘探:进展与启示 总被引:3,自引:0,他引:3
干热岩是地热资源的重要赋存形式之一,是未来地热开发的主攻方向。我国干热岩勘查工作近年来进展迅速,先后在不同地区发现了优质的干热岩资源,取得了我国干热岩资源勘查突破,但同时也存在不少勘查失败的案例。本文在分析高放射性产热型、沉积盆地型、近代火山型和强烈构造活动带型等四种类型干热岩成因模式的基础上,结合我国的地质构造背景、地热地质条件,对未来我国干热岩资源重点勘查方向及靶区进行了论述,并重点针对目前不同类型区干热岩资源勘探工程进行了梳理,简要分析了不同勘探区的选址依据、勘探过程、地温场分布及特征、前景预测等,并初步进行了经验总结,希望对我国未来干热岩资源勘查及开发工作起到借鉴作用。 相似文献
47.
录井检测受井场环境影响较大,主要包括钻井环境与检测环境,钻井环境包括井径、钻时、钻井液排量、是否取心等,检测环境主要是井场自然环境与检测器内部环境。一般情况下检测器内部环境基本一致,而井场自然环境在一定时间内变化不大,故而钻井环境对录井检测的影响较大,钻井环境校正是进行录井解释前的重要工作。常规Tg(全烃含量)校正方法在取心、低异常、多互层等层段使用效果较差,经过分析,将校正方法在取心、钻时、排量、基值方面进行优化,实践验证,新校正方法效果较好,适应了西湖凹陷的地质研究需求。 相似文献
48.
Based on the tested data of pressure and vitrinite reflectance of some wells in sedimentary basins, abnormal high pressure
is regarded as not the only factor to retard the increase of vitrinite reflectance (R
o). Apart from the types of the organic matter, the physical environment (temperature and pressure) and chemical environment
(fluid composition and inorganic elements) will result in the abnormal vitrinite reflectance values in the sedimentary basins.
This paper tested trace elements and vitrinite reflectance data from the the abnormal high pressure and normal pressure strata
profiles, respectively, and found that the acidic and lower salinity starta are favorable for the increase of R
o. By discussing the corresponding relationship between the contents of some trace elements in the mudstone and the vitrinite
reflectance values, the typical trace elements were found to suppress and/or catalyze the vitrinite reflectance of organic
matter, while the elements of Ca, Mn, Sr, B, Ba and P may result in the retardation of R
o. However, elements of Fe, Co, Zn, Ni and Rb may catalyze the organic matter maturation. This study is conductive to the organic
maturation correction, oil and gas assessment and thermal history reconstruction by the paleothermometry.
Translated from Acta Geologica Sinica, 2006, 80(11): 1760–1769 [译自: 地质学报] 相似文献
49.
50.
Toward micro-scale spatial modeling of gentrification 总被引:1,自引:0,他引:1
David O'Sullivan 《Journal of Geographical Systems》2002,4(3):251-274
A simple preliminary model of gentrification is presented. The model is based on an irregular cellular automaton architecture
drawing on the concept of proximal space, which is well suited to the spatial externalities present in housing markets at
the local scale. The rent gap hypothesis on which the model's cell transition rules are based is discussed. The model's transition
rules are described in detail. Practical difficulties in configuring and initializing the model are described and its typical
behavior reported. Prospects for further development of the model are discussed. The current model structure, while inadequate,
is well suited to further elaboration and the incorporation of other interesting and relevant effects.
Received: 1 November 2001 / Accepted: 12 April 2002
Town centres data were made available by kind permission of the UK Department of the Environment, Transport and the Regions. 相似文献