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101.
Reconstructed sunspot data are available that extend solar activity back to 11 360 years before the present. We have examined
these data using Hurst analysis, a moving average filter, and Fourier analysis. All of the procedures indicate the presence
of a long term (≈6 000 year) cycle not previously reported. A number of shorter cycles formerly identified in the literature
by using Fourier analysis, Bayes methods, and maximum entropy methods were also detected in the reconstructed sunspot data. 相似文献
102.
The UK is witnessing a new line in political debate around new nuclear energy generation as one potential feature of future energy policy, specifically for contributing to climate change mitigation alongside energy security. Little is known about how ordinary citizens might be responding to this reframing. This paper reports the results from a major British survey (n=1491) undertaken in the autumn of 2005. The consistent message is that while higher proportions of the British public are prepared to accept nuclear power if they believe it contributes to climate change mitigation, this is a highly conditional view, with very few actively preferring this over renewable sources given the choice. People see both climate change and nuclear power as problematic in terms of risks and express only a ‘reluctant acceptance’ of nuclear power as a ‘solution’ to climate change. The combined data from this survey can also be interpreted as an indication of the complexity surrounding beliefs about energy futures and the difficulty of undertaking simplistic risk–risk tradeoffs within any single framing of the issues; such as nuclear energy versus climate change. The results also indicate that it would be unwise, in the UK as elsewhere, to simplistically assume that there exists any single or stable public ‘opinion’ on such complex matters. We conclude with a discussion of the role and implications of the survey evidence for the policy process. 相似文献
103.
104.
伊犁京希—伊尔曼德金矿床的热液蚀变及成矿流体演化特征 总被引:10,自引:1,他引:10
京希-伊尔曼德金矿床的热液蚀变在空间上有明显的分带性,中心蚀变带以强烈的硅化为主,典型的蚀变矿物组合为石英或玉髓和地开石,中间带为高级泥化带,以地开石-高岭石-石英或玉髓为特征;外带为以蒙脱石-高岭石-伊利石-其他粘土矿物等矿物组合为主的泥化带,蚀变强度和矿物组合的分带性是温度、压力和化学梯度的反映,是流体在不断的水或流体-岩石反应和成分交换的产物。该矿床成矿流体演化过程为:早期酸性(pH=2-3)含矿流体在沿断裂上升过程中,受围岩灰岩中的流体(pH为中性)缓冲,在其进入高渗透性的碎屑岩层时,流速和水-岩石或流休-岩石反应大大加快,并在与大气降水的混合作用下,pH值逐步升高(3-5),产生了流体的温度及成分梯度,在温度和压力迅速下降的条件下,金及蚀变矿物沉淀、结晶生长,形成了蚀变空间分带,中心带保存完好的多孔状石英和地开石等高级泥化矿物组合说明该矿床是高硫化热液体系作用下的产物。 相似文献
105.
Raman microspectrometry of fluid inclusions 总被引:45,自引:0,他引:45
Ernst A. J. Burke 《Lithos》2001,55(1-4):139-158
For many kinds of fluid inclusions, the coupling of microthermometry and Raman microspectrometry is still the only viable option to obtain compositions of single fluid inclusions. A review is given on the basis of 16 years of experience and helped with about 120 references of the instrumentation, analytical conditions and methodology of the application of Raman microspectrometry to gaseous, aqueous and hydrocarbon inclusions, and their daughter minerals. 相似文献
106.
The Basement Complex in Western Nigeria in general, and in the Ibadan area in particular, is composed primarily of a banded gneiss in which hornblende-biotite rich bands alternate with quartz-oligoclase rich bands. The banded gneiss, which originated as part of a sedimentary sequence, contains large lenses of granite gneiss and thin intercolated layers of quartzite and amphibolite.Two distinct major structural events can be clearly identified in the early geological history of the Ibadan area. Detailed field studies suggest that the formation of the Ibadan Granite Gneiss, which had yielded an Eburnean Rb-Sr isochron age, was associated with the later of these events. Five phases of dyke or vein formation, two of which pre-date the formation of the Granite Gneiss, have also been identified giving an overall sequence of geological events the first of which may correspond to the beginning of the Liberian orogeny, around 3000 m.y. ago, and the last of which reflects the waning of the Pan-African thermo-tectonic event about 500 m.y. ago. 相似文献
107.
Sbil Seitzinger Scott Nixon Michael E.Q. Pilson Suzanne Burke 《Geochimica et cosmochimica acta》1980,44(11):1853-1860
Methods were developed for determining rates of denitrification in coastal marine sediments by measuring the production of N2 from undisturbed cores incubated in gas-tight chambers. Denitrification rates at summer temperatures (23°C) in sediment cores from Narragansett Bay, Rhode Island, were about 50μmol N2m?2 hr?1. This nitrogen flux is equal to approximately one-half of the NH+4flux from the sediments at this temperature and is of the magnitude necessary to account for the anomalously low N/P and anomalously high O/N ratios often reported for benthic nutrient fluxes. The loss of fixed nitrogen as N2 during the benthic remineralization of organic matter, coupled with the importance of benthic remineralization processes in shallow coastal waters may help to explain why the availability of fixed nitrogen is a major factor limiting primary production in these areas. Narragansett Bay sediments are also a source of N2O, but the amount of nitrogen involved was only about 0.2 μmol m?2 hr?1 at 23°C. 相似文献
108.
109.
This paper explores the theoretical content of the inner-city debate in Britain and seeks to examine the extent to which the ‘problem’ is either new or primarily economic. It is argued that the inner-city issue, while subject to specific political and ideological forces, is associated with the general processes of uneven capitalist development. In this sense, metropolitan decline is a further manifestation of the relationship between the built environment, the transience of economic activity and social change. More specifically the decline of the inner city relates to the incipient role of Britain in the development of capitalism and its current position in the world economy. The emergence of this as a ‘problem’ for the British state is combined with a convenient spatial determinism, which isolates the inner city as an anomaly even as the search for palliatives is erected to the status of a major social task. 相似文献
110.