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81.
In this essay a method of computing tourism climatic indices (TCIS) is described. These indices represent a quantitative evaluation of world climate for the purposes of international tourism. A series of rating systems is developed to provide a systematic basis for assessing the climatic elements that most affect the quality of the tour- ism experience. The problem of weighting climatic variables in the TCI formula is also discussed. Monthly TCIS have been computed for 453 meteorological stations throughout the world, and the results have been generalized in 12 monthly world maps.
L' article offre une méthode pour calculer des indices climatoogiques touristiques (ICT), qui représentent une évaluation quantitative des climats mondiaux, destinée aux besoins du tourisme international. On développe une série de systèmes d' évaluation d' éléments climatologiques, fournissant ainsi une base systématique pour évaluer lesquels de ces derniers influencent le plus la qualityé de l' expérience touristique vécu. L'article souléve aussi les problhes réliés aux valeurs relatives, soient les poids, des variables qui entrent dans la formule de l' ICT. Des valeurs mensuelles ont été compilées pour 453 stations météorologiques à travers le monde, et les résultats sont présentés, en forme généralisée sur une base mensuelle, dans douze cartes mondiales.  相似文献   
82.
Since 2000 there have been major changes in the agrarian economy in Zimbabwe. Extensive land redistribution and severe macro‐economic instability have resulted in significant shifts in agricultural production and the functioning of markets, opening opportunities for some and closing options for others. This article focuses on cattle in Masvingo Province, identifying current patterns and dynamics and future challenges. Key to the analysis is an understanding of the social and political embeddedness of real markets and the relationship between the state and an increasingly informal, sometimes illegal, economy. The article traces the transformation of a formalized beef production and marketing system, organized around a relatively narrow group of players, to a more fragmented, diverse and complex system with a different — and potentially wider — scope and reach. It highlights a series of phases, from the technocratic order of the colonial era, and its replication in the period following Independence, to a new situation following land reform. Although there have recently been attempts to reinstate a particular order through price controls and other measures, this has had little impact. The result is a radically reshaped production and market system, which suggests very new political and social relationships for the livestock sector.  相似文献   
83.
Although many hydrologic changes induced by teleseismic waves have been reported, the mechanism(s) responsible for the changes are usually not known. Permeability changes induced by seismic strains are often invoked to explain changes in water level. Using water‐level data in Taiwan after the 2008 Wenchuan earthquake, we show here that the observations cannot be properly explained by previously proposed models of postseismic permeability changes. A new model is required in which the postseismic permeability decreases exponentially as a function of time, with a time constant of <3 min, which is appreciably shorter than inferred from earlier studies. The result may have important implications for pore‐sealing mechanism(s).  相似文献   
84.
We report new optically stimulated luminescence (OSL) dates from the Central European sites of K?lna, Stránská skála, Bohunice, Vedrovice V, Vedrovice Ia, Moravský Krumlov IV and Dzeravá skala, which date to the Middle–Upper Palaeolithic transition period. There are important unresolved questions surrounding the timing of archaeological events during this crucial period in European prehistory. Archaeological layers from this time period are at the limits of the 14C method and most of these sites lack good chronology. The results of this dating project suggest that some parts of the current chronological framework may need to be revised. Although in many cases our OSL results are broadly consistent with previous dates obtained by 14C, in other cases they reveal unexpected surprises. One OSL result from K?lna opens up the possibility that Neanderthals may have survived in this part of Europe past the 30 ka bp mark as has been argued for several Neanderthal sites in southern Europe. The large Szeletian assemblage recovered from Vedrovice V may be significantly older than previously thought, which undermines the idea that the Szeletian culture is exclusively an Early Upper Palaeolithic industry. More dating research is needed to confirm the more controversial results of this research.  相似文献   
85.
Y. Li  C. Ma  G. Juleff  Y. Murakami  Z. Zhou  Y. Li 《Archaeometry》2019,61(6):1353-1365
Xuxiebian is an iron‐smelting site located in Pujiang county of Sichuan province, China. Two excavations were carried out in 2007 and 2011, and four bowl‐shaped furnaces were excavated. Ten slag samples from the site were prepared and analysed. The present paper reports the results of metallographic and elemental examination of the specimens. It is concluded that both pig‐iron‐smelting and refining process were applied at the Xuxiebian site, and the bowl‐shaped furnaces are possibly refining furnaces. The function of the site was probably to produce pig iron and refine the pig iron into wrought iron.  相似文献   
86.
Twenty-four cast copper crotals (commonly called bells), one 'spilled bell’, one tinkler bell and a number of minerals from locations throughout the Greater Southwest were analysed for their elemental composition by a PIXE nuclear microprobe at Los Alamos National Laboratory, New Mexico, USA. Sixteen bells contained minor and trace amounts of silver, antimony, arsenic, lead, and in some cases tin, strontium, and selenium. Nine bells contained little or no detectable amounts of these elements. This suggests that several workshops throughout the Greater Southwest and Mexico might have manufactured these bells.  相似文献   
87.
88.
Y. Song  Z. Hou  Y. Cheng  T. Yang  C. Xue 《Geofluids》2016,16(1):56-77
Extensive quartz–carbonate–Cu sulfide veins occur in clastic rocks and are spatially related to Paleocene granites in the western border of the Lanping Basin, western Yunnan, China. Abundant aqueous‐carbonic fluid inclusions occur in these veins but their origin is debated. In the Jinman–Liancheng deposit, individual primary inclusion groups contain either exclusively liquid‐rich inclusions (Gl), or coexisting liquid‐rich and vapor‐rich inclusions (Glv). Microthermometry and estimate of CO2 content indicate that type Gl inclusions either have homogenization temperatures (Th) 238–263°C and contain c. 3.9–5.5 mole % CO2, or have Th 178–222°C and contain c. 1.6–3.2 mole % CO2. Type Glv inclusions are thought to represent samples of fluid unmixing that occurred at 183–218°C. At that time, the liquid phase in the unmixing fluid may contain c. 2.0–3.3 mole % CO2. As such, the correlation of CO2 content with Th for type Gl inclusions is thought to be caused by fluid unmixing with decreasing temperature and subsequent CO2 escape. δ18O and δD values of the parent water mainly fall in the field below that of primary magmatic water, indicative of fluid derivation from degassed (in open system) magmatic water, with no contributions from basinal or meteoric water. Initial Sr isotopic compositions of hydrothermal carbonates suggest that the fluid was magmatic, probably derived from the Paleogene granites. δ13CPDB values (?4‰ to ?7‰) of the hydrothermal carbonates and δ34SVCDT values of sulfides (mainly ?11‰ to +5‰) indicate that the carbon and sulfur can be derived from (degassed) magma and/or nonmagmatic sources. The CO2‐rich and magmatic‐water‐derived fluid at Jinman–Liancheng differs from the CO2‐poor and basinally derived fluid in sediment‐hosted stratiform Cu (SSC) deposits, which suggests that there are no genetic linkages between the vein Cu and SSC deposits in the Lanping Basin.  相似文献   
89.
X. W. Guo  K. Y. Liu  S. He  Z. Yang  T. T. Dong 《Geofluids》2016,16(1):129-148
Hydrocarbon generation can yield high fluid pressures in sedimentary basins as the conversion of solid kerogen to hydrocarbons can result in an increase in fluid volume. To quantify the relationship between gas generation and overpressure in source rocks, a set of equations for computing the pressure change due to gas generation has been derived. Those equations can be used to quantitatively estimate overpressure generated by type III kerogen in source rocks by considering gas generation and leakage, gas dissolution in formation water and residual oil, thermal cracking of oil to gas, and hydrocarbon episodic expulsion from source rocks. The equations also take consideration of other factors including source rock porosity, transformation ratio, total organic carbon (TOC), hydrogen index, and compressibility of kerogen, oil, and water. As both oil and gas are taken into account in the equations, they can also be used to estimate the evolution of overpressure caused by hydrocarbon generation of type I and type II kerogen source rocks. Sensitivity analyses on the type III kerogen source rock indicate that hydrogen index is the most influential parameter for overpressure generation, while TOC and residual gas coefficient (β: ratio of residual gas over the total gas generated) have a moderate effect. Overpressure can be generated even if the gas leakage/loss in the source rock is up to 80% of the total gas generated. This suggests that the internal pressure seal of the source rock is not a critical factor on the pressure change as long as the source rocks are capable of sealing liquid oil. The equations were applied to evaluate the overpressure in the Eocene–Oligocene Enping Formation source rocks due to hydrocarbon generation in the Baiyun Depression, the Pearl River Mouth Basin by considering the source rock properties, hydrocarbon generation history, and hydrocarbon expulsion timing. Two episodes of overpressure development due to gas generation and release were modeled to have occurred in the Enping Formation source rock since 16 Ma. The overpressure release at 10.2–5.3 Ma via hydrocarbon expulsion was apparently related to the Dongsha phase of tectonic deformation, whereas the pressure release at 2–0 Ma was due to pressure generation that was exceeded the fracture‐sealing pressure in the source rocks.  相似文献   
90.
Living bone sequesters environmental lead (Pb) from both inhalation and ingestion, providing a record of Pb exposure over a lifetime. Questions about the effects of diagenesis and how to remove them have hampered most isotopic and elemental determinations. As a result, researchers often restrict their analyses to tooth enamel, despite its limitations. We report Pb isotopes in teeth and bones in a frontier population of 15 individuals from a late 19th century mental hospital graveyard in Pueblo, Colorado, a town active at that time in the smelting of ores. Analysis of lead isotopes sequestered in healing bone from rib fractures gives an isotopic fingerprint from the last few months of individual's lives. When bone tissues or teeth from different stages of life are analysed, life history trajectories such as migration routes can be developed which are partially self‐correcting for diagenesis. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   
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