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161.
关于第三产业与区域经济发展关系的基本认识 总被引:2,自引:1,他引:2
通过简要评介产业结构化,初略回顾和分析国内外第三产业发展的历史经验,提出并强调要认识第三产业与区域经济发展的关系,必须坚持历史和区域的观点。 相似文献
162.
Source rock evaluation is a critical factor in resource assessment of oil and gas. Models for evaluating source rocks are
dependent on established geomathematical principles, the calculation of source-rock parameters, and geological data. The sensitivities
and uncertainties associated with these models are a matter of concern. In this paper, the effects and relative contributions
of 13 major geological factors, as well as their variations and distribution probabilities, have been analyzed for the source
rocks in the North Songliao Basin in northeastern China. The geological factors include the time of formation of the regional
caprock, composition of the regional caprock, the phases of hydrocarbons in migration, and those factors associated with the
generation, retention, and expulsion of hydrocarbons and their effects on source-rock efficiency. Of the 13 factors analyzed,
the most important are the source-rock depth, sedimentation rate, total organic content, and kerogen-type index; the relative
contributions to the uncertainty of efficient gas/oil migration amounts for the most important factors are 37, 25, 19, and
1% for oil and 32, 17, 20, and 15% for gas, respectively. These most reflect the changes that have occurred in the Qingshankou
source rocks. 相似文献
163.
Metallogenesis of Devonian—Carboniferous Strata—bound Carbonate—type Uranium Deposits in South China
庞玉蕙 《中国地球化学学报》1990,9(3):264-274
This paper deais with the geological conditions.mineralization characteristics,genetic types and space-time distribution of the Devonian-Carboniferous strata-bound carbonate-type uranium deposits in South China.These ore deposits are genetically classified as the leaching type and the leaching-hydrothermal superimposed type,These ore deposits are confined mainly to the strata (D2-3,C1)of platform-lagoon carbonate facies.Unique tectonic settings are a vital factor leading to the formation of these uranium deposits.A metallogenetic model for these uranium deposits has been proposed. 相似文献
164.
关于中国世界城市发展条件与前景的初步研究 总被引:5,自引:0,他引:5
本文简要回顾了"世界城市"的理论背景及国内有关建设国际性中心城市的设想,根据世界城市的概念体系和理论框架,重点分析了中国建设世界城市的可行性和主要制约因素,并对中国未来世界城市的发展前景进行了初步评价。 相似文献
165.
166.
黔中茶店桥地下河流域不同水体硫酸盐浓度特征及来源识别 总被引:8,自引:0,他引:8
茶店桥地下河位于西南岩溶区,流域内"三水"转换迅速,地下水是当地的重要饮用水源。本文对流域内雨水、地表水、地下水中的SO_4~(2-)浓度进行了测试,利用氘(δD_(H_2O))、氧(δ~(18) O_(H_2O))同位素示踪地表水、地下水补给来源,用硫酸盐硫(δ~(34)S_(SO4))、氧(δ~(18) O_(SO4))同位素探讨了地表水、地下水中SO_4~(2-)的来源,并计算了地下河出口河水中不同SO_4~(2-)来源的贡献比例。结果表明:1不同水体中SO_4~(2-)浓度大小顺序为地表水地下水雨水,与邻近区域相比,茶店桥地下河流域雨水、地表水、地下水呈现富集SO_4~(2-)的特征。2地表水、地下水的主要补给来源为大气降水,硫酸不仅和HCO_3~-共同参与了流域内碳酸盐岩的溶解,也参与了雨水中含钙镁颗粒物的溶解。3地表水δ~(34)S_(SO4)、δ~(18) O_(SO4)值分别介于-12.98‰~-10.19‰和-0.54‰~+9.13‰之间,地下水δ~(34)S_(SO4)、δ~(18) O_(SO4)值分别介于-14.32‰~+16.58‰和+2.81‰~+14.35‰之间,SW02的SO_4~(2-)主要来源于大气降水,SW01、SW03、GW02、GW03、GW06主要来源于煤层,GW05主要来源于石膏,GW01、GW04为混合输入源。4地下河出口河水中大气降水带来的SO_4~(2-)贡献比例为13%,煤层硫化物氧化的贡献比例为40%,石膏溶解的贡献比例为47%。 相似文献
167.
168.
Recent studies in the western North Pacific reported a declining standing stock biomass of anchovy (Engraulis japonicus) in the Yellow Sea and a climate-driven southward shift of anchovy catch in Korean waters. We investigated the effects of a warming ocean on the latitudinal shift of anchovy catch by developing and applying individual-based models (IBMs) based on a regional ocean circulation model and an IPCC climate change scenario. Despite the greater uncertainty, our two IBMs projected that, by the 2030s, the strengthened Tsushima warm current in the Korea Strait and the East Sea, driven by global warming, and the subsequent confinement of the relatively cold water masses within the Yellow Sea will decrease larval anchovy biomass in the Yellow Sea, but will increase it in the Korea Strait and the East Sea. The decreasing trend of anchovy biomass in the Yellow Sea was reproduced by our models, but further validation and enhancement of the models is required together with extended ichthyoplankton surveys to understand and reliably project range shifts of anchovy and the impacts such range shifts will have on the marine ecosystems and fisheries in the region. 相似文献
169.
Ultraviolet complex refractive index of Martian dust: Laboratory measurements of terrestrial analogs
The optical complex index of refraction of four candidate Martian surface materials has been determined between 0.185 and 0.4 μm using a modified Kubelka-Munk scattering theory. The candidate materials were limonite, andesite, montmorillonite, and basalt. The effect of scattering has been removed from the results. Also presented are diffuse reflection and transmission data on these samples. 相似文献
170.
The Mariner 9 ultraviolet spectrometer observed the brightness of a region on the south polar cap centered at approximately ?87°S, 10°W. Measurements taken at various incidence and emission angles (i and ?) show that the brightness increased with decreasing air mass, ≈(sec i + sec ?). The observed intensity consists primarily of a component reflected from the cap and twice-attenuated by the atmosphere and a component diffusely reflected from the atmosphere. The diffusely reflected component was determined from nearby observations of non-polar regions at the same incidence and emission angles and was substrated from the total intensity. Inversion of the intensity difference using a formula analogous to the Bouger-Langley law yielded the optical thickness of the atmosphere. The dust cloud over the polar cap was moderately thick between November 26 and December 2, 1971. At this time the optical thickness was near unity, and it decreased approximately linearly with time, reaching a value close to that of a Rayleigh atmosphere by mid-February. The optical thickness showed little dependence on the wavelength during the early orbital observations. As the dust storm cleared, the atmospheric optical thickness exhibited increasingly strong inverse wavelength dependence. Particles large compared with the wavelength dominated the Martian dust storm. These particles are estimated to have a mean radius of about 2 μm. 相似文献