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111.
Sarkar Dipu Ao Taliakum Gunturi Sravan Kumar 《Theoretical and Applied Climatology》2022,148(3-4):1111-1125
Theoretical and Applied Climatology - Electricity is an essential commodity that must be generated in response to demand. Hydroelectric power plants, fossil fuels, nuclear energy, and wind energy... 相似文献
112.
In the past, researchers tried hard classification techniques with contextual information to improve classification results. While modelling the spatial contextual information for hard classifiers using Markov Random Field it has been found that the Metropolis algorithm is easier to program and it performs better when compared with the Gibbs sampler. In this study, it has been found that in the case of soft contextual classification, the Metropolis algorithm fails to sample from a random field efficiently and the Gibbs sampler performs better than the Metropolis algorithm, due to the high dimensionality of the soft classification outputs. 相似文献
113.
114.
Landslips are often triggered due to non-engineered excavation of potential unstable slopes. Such slips can be stabilized by implementing suitable remedial measures.A landslip occurred at a drilling site of Oil India Limited in Mizoram State due to slope excavation. There was an immediate concern to protect the slope as the drilling platform and the highway at the top of the slope are at risk if further landslide occurs in future. Slope stability analysis of the failed slope was carried out to design suitable control measures for the protection of the slope from further sliding. Slope stability using various methods indicated that the slope is marginally stable. To improve the stability of the slope, suitable retaining structure at the toe of the slope was suggested and designed. Stability analysis performed with inclusion of retaining wall showed a significant increase in factor of safety of the slope. The suggested remedial measure has been implemented at the site and there is no landslip reported since then. The paper presents the results of the slope stability analysis and the design details of the retaining structure prescribed as the protection measure. 相似文献
115.
Stability of slope will always a problem due to its geodynamic nature of Himalayan region. The area investigated belongs to the Lower Siwalik formation, which is prone to failure due to presence of various weak planes or structures present in the rock mass. Frequent landslides causing loss of life, property, disturbance of morphological, surface and subsurface water flow pattern. A huge landslide in the Amiyan area occurred in 1999 and blocked the Gaula River which caused loss of agricultural land and other properties as well as waterlogged upstream side. The debris of Amiyan slope contains soil and sandstones of various types. This article deals with instability analysis of slopes of the Amiyan area, near Kathgodam, Nainital, Uttarakhand. This area experiences a number of local as well as regional slides. Extensive field surveys have been carried out to understand the geological detail. Laboratory experiments have been conducted to determine the various physicomechanical properties of rock mass. These properties have been used as input parameters for the numerical simulation. A number of researchers have used two-dimensional numerical models to simulate the slide area. Three-dimensional slope stability studies provide a better understanding of the mechanism of failure as well as zone of influence. The computed deformations and stress distribution, along the failure surface, have been compared with the field measurements and found to be in good agreement with field observations. In this case, finite difference method has been applied on the stability analysis of Amiyan slope. The study indicates that the slope is vulnerable and needs proper protection. 相似文献
116.
Santanu Banerjee Shovan Lal Chattoraj P. K. Saraswati Somnath Dasgupta Urbashi Sarkar Adam Bumby 《Geological Journal》2012,47(4):357-371
An integrated study of the sedimentology, micropalaeontology, mineralogy and geochemistry of glauconites in the Oligocene Maniyara Fort Formation (western Kutch, India), has been undertaken. Authigenic glauconites, mostly of evolved type, formed within a back‐barrier lagoonal environment. Foraminifera help constrain the biostratigraphy and along with sedimentological evidence, provide information on the depositional conditions. Glauconite in the Maniyara Fort Formation occurs either as infillings within intra‐particle pores of larger foraminifers, or as an altered form of faecal pellets. X‐ray diffraction studies reveal the less mature nature of glauconite infillings compared to the glauconite pellets. Electron microprobe investigation confirms a relative enrichment of K2O and total Fe2O3 in the latter. Both varieties of glauconite formed by initial authigenic precipitation of K‐poor glauconite and subsequently matured by addition of potassium in the interlayer sites and fixation of total iron in the octahedral sites; calcium, magnesium and aluminum were released from the glauconite structure concomitantly. Alkaline conditions during the entire process of glauconite formation did not allow dissolution of foraminiferal tests. Mineralogical and chemical characteristics of the Maniyara Fort Formation glauconites are more similar to deep marine glauconites than those reported from other shallow or marginal marine settings. A low negative cerium anomaly, as well as abundant pyrite, suggests formation of glauconite in sub‐oxic micro‐environments, created by decay of organic matter associated with foraminiferal chambers and faecal pellets. Sub‐oxic condition apparently prevailed relatively longer within the Maniyara Fort Formation lagoons. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
117.
We investigate the dynamical behavior of a magnetized, dissipative accretion flow around a rapidly rotating black hole. We solve the magnetohydrodynamic equations and calculate the transonic accretion solutions which may contain discontinuous shock transitions. We investigate the effect of ζ-parameter(parametrizing the radial variation of the toroidal magnetic flux advection rate) on the dynamical behavior of shocks. For a rapidly rotating black hole and for fixed injection parameters at the outer edge, we show that stationary shocks are sustained in the global magnetized accretion solutions for a wide range of ζ and accretion rate( ˙m). To investigate the observational implications, we consider dissipative shocks and estimate the maximum accessible energy from the post-shock corona(PSC) for nine stellar mass black hole candidates. We compare this with the observed radio jet kinetic power reported in the literature, whenever available. We find close agreement between the estimated values from our model and those reported in the literature. 相似文献
118.
Morishita Tomoaki Ghosh Biswajit Soda Yusuke Mizukami Tomoyuki Tani Ken-ichiro Ishizuka Osamu Tamura Akihiro Komaru Chihiro Aari Shoji Yang Hsiao-Chin Chen Wen-Shan 《Mineralogy and Petrology》2018,112(4):521-534
Mineralogy and Petrology - We examine ultramafic and olivine-rich troctolite blocks of the East Taiwan Ophiolite (ETO) in the Lichi Mélange. Although ultramafic rocks are extensively... 相似文献
119.
Madhuparna Paul Jyotisankar Ray C. Manikyamba Sohini Ganguly M. Rajanikanta Singh Saraswati Pachal Debaleena Sarkar 《Geological Journal》2021,56(1):102-129
Precambrian mafic magmatism is an important global episode which played a significant role in the crustal evolution. In India, Singhbhum Craton being the oldest craton, witnessed significant occurrences of Precambrian geological activity, marked by several episodes of volcanism, plutonism, sedimentation spanning from Palaeoarchean to Mesoproterozoic age. Here we present petrological and geochemical characteristics of Precambrian mafic volcanic rocks (occurring in western Iron Ore Group (IOG), Singhbhum Craton, eastern India) to evaluate their petrogenetic aspects, tectonic setting, and magma generation. The mafic volcanic rocks are porphyritic in nature with the phenocrysts of plagioclase and groundmass composed of clinopyroxene, plagioclase, ilmenite, and volcanic glass. These rocks are mostly tholeiitic, sometimes with a transitional behaviour towards calc-alkaline nature and display basalt-basaltic andesite affinity. These mafic volcanic rocks also preserve geochemical signatures (high Nb/U, Nb/La, [Nb/Th]pm ratios) in support of Nb-enriched basalts and are classified as Nb-enriched basalts (NEB; Nb > 7 ppm) and high-Nb basalts (HNB; Nb > 20 ppm) on the basis of Nb concentrations and mantle normalized Nb/La ratios (>0.5). The NEBs and HNBs are marked by lesser magnitude of negative Nb anomalies with high (Nb/Th)pm, (Nb/La)pm, and Nb/U ratios as compared to normal arc basalts. Several major element oxides, trace elements, and selected element ratios (like SiO2, CaO/Al2O3, Y, V/Cr, Zr/Nb, and ∑REE) show systematic variations with MgO which suggests role of magmatic fractionation. Chondrite-normalized REE patterns for NEB and HNB rocks exhibit uniform LREE enrichment with distinct Eu negative anomalies while primitive mantle-normalized incompatible trace element patterns reflect enrichment in LILE and LREE with prominent Nb-Ta anomalies. Different HFSE ratios corroborate a subduction related setting for magma generation formed by ∼10%–20% melting in the domain of garnet lherzolite. Relative enrichment of LILE and LREE with depleted HFSE characteristics attest a garnet-bearing mantle source and melt extraction with garnet in the residue. Geochemical signatures suggest that the genesis of NEB and HNB is attributable to slab-melting and wedge hybridization processes during matured stages of subduction. Selected incompatible trace element ratios for the studied mafic volcanic rocks invoke an enriched (EM1-EM2 type) mantle source and unequivocally suggest effects of continental crustal assimilation of the parent magma. Liquid immiscibility has played an important role as a differentiation mechanism leading to presence of high and low FeO types. The IOG mafic volcanic rocks preserve distinct geochemical signatures of matured stage of subduction, slab melting, crustal contamination and magma generation at an Archean ocean–continent convergent margin setting. 相似文献
120.
Pseudotachylyte (Pt) veins associated with ancient fault zones are considered as reliable palaeoseismic indicators as they are produced by a combination of cataclasis and frictional melting of the host rock during rapid (seismic rate) fault slip. In spite of a large amount of work done on pseudotachylytes, several issues related to the frictional melting process are not completely resolved for example, the nature and origin of domain-scale chemical heterogeneity of the Pt matrix, the contribution of different minerals of the host rocks in forming the melt product, temperature variation in different domains of the Pt veins, among others. To revisit these issues, pseudotachylyte veins hosted entirely within pelitic gneisses (Pt-I) and those formed along the contact of gneisses with intrusive meta-dolerite dykes (Pt-II) within the Sarwar-Junia Fault Zone in Rajasthan, India, are studied in detail using optical and scanning electron microscope, X-ray diffraction (XRD), X-ray fluorescence, and electron probe micro-analyser, with an intention to better understand the evolution of the microstructures and the heterogeneous chemical character of the pseudotachylyte veins and their host rocks. Unequivocal melt-origin microstructures (e.g., microlites, spherulites, melt flow structure) are observed in the pseudotachylyte matrix, and an indirect evidence of amorphous (glass?) phase is found through XRD. The Pt-matrix is more mafic than the host rock or the bulk Pt-vein, irrespective of the rock types involved, indicating preferential melting of mafic minerals of the host rock(s). Microdomain-scale variation in mineralogical and chemical character of Pt-matrix suggests co-existence of melts of different composition which remained unmixed due to rapid quenching of the melt. Mineral chemistry of fine microlites and spherulites within the Pt-matrix differs significantly from the corresponding parent mineral grains in the respective host rocks suggesting their formation by direct crystallization from a melt phase. Formation of microlites by devitrification of solidified glass is discounted due to the absence of fluid activity, and due to the spatial distribution of finer microlites (near the Pt-vein boundary), and coarser spherulites (near the centre). It is surmised that frictional heating attains different temperatures within a single Pt-vein, and in adjacent Pt-veins, and the constituent minerals melt selectively as the temperature rises beyond the melting points of different constituent minerals of the host rock. Neither preferential crushing of mafic minerals followed by bulk melting, nor eutectic (equilibrium) melting of the host rock can explain the strongly heterogeneous character of pseudotachylyte melt observed in this study. 相似文献