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41.
Waterlogged archaeological wood undergoes decay processes that depend on both the burial conditions and the constituting species, and which cause the depletion of the structural components of wood cells. To quantitatively assess the state of preservation of the decayed material, specific parameters are usually measured by means of both chemical and physical analyses. In this paper an innovative approach in the use of the data obtained from these kinds of measurements is developed. A series of 132 archaeological wood samples of different wood species, burial times and states of preservation, and coming from different sites in Italy, was analysed. Their residual chemical composition, maximum water content and basic density were measured, and a reasoned use of these parameters was carried out through their elaboration, with the aim of both evaluating eventual incongruence or anomalies in the raw physical and chemical data (which has never been accomplished so far) and directly comparing in a reliable way the analytical results obtained from archaeological samples with very different states of preservation. This approach allowed defining the effective values of chemical parameters related to wood decay according to a same reference basis of calculation among the various data. By this way, it was possible to state that lignin can be also attacked by the agents causing biotic decay, and that in hardwoods its decay is more related to the burial conditions than to the wood species. Instead, the mechanism of polysaccharide depletion is diversified: conifers showed a uniform behaviour whereas hardwoods were more species-dependent. Moreover, in addition to the chemical composition, also anatomical factors influence the carbohydrate rate of decay in waterlogged wood. 相似文献
42.
Metallographic examination was carried out on forty-nine copper and bronze objects from five megalithic sites located in Vidarbha, India. The artifact assembly consists of horse ornaments, kitchenware, bangles, rings, small bells and the hilt of an iron dagger. Results show that the technology involved is characterized by the use of bronze alloys containing approximately 10% tin based on weight and the application of forging as a key method of fabrication. No deliberate addition of lead was observed. Arsenic was detected, but very rarely and only as an insignificant minor element. The consistent selection of such specific alloys indicates that the megalithic communities in this particular region had established a fully developed and standardized bronze tradition optimized for the production of forged items. Their advanced technological status was also noted in a special technique applied to two forged high-tin bronze bowls. Such a unique bronze tradition, dedicated to sheet metal technology, was most likely a practical choice made by these people to take advantage of the changing role of bronze. Specifically, with the introduction of iron, bronze seems to have become a more prestigious material that could serve as an indicator of the appearance of a more rigid socio-economic stratification within the megalithic communities of the Vidarbha region. 相似文献
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44.
气候对中国古代塔砖材料性能劣化影响的研究 总被引:2,自引:1,他引:1
在气候影响下,塔砖材料性能的劣化加剧了中国古塔结构的损伤,减少了古塔的结构寿命。为此,课题选择两个极具代表性的中国古代砖塔—1500年历史的嵩岳寺塔和1200年历史的法王寺塔进行同一性研究,欲证明两塔在地理位置、环境气候、形制、塔体古砖制造原料和制造工艺等方面均具有很强的相似性和同一性。采用X射线荧光光谱法分析了两塔塔砖的材料成分,采用压汞法对两塔塔砖材料的孔隙率、孔隙结构和孔隙分布特征进行了实验。两塔塔砖材料实验结果的差异证明:在公元5世纪到公元8世纪的300年气候影响下(该气候为自然营力而非实验室人工模拟),塔砖材料孔隙率的增大是导致中国古代塔砖性能劣化的主要原因,大约30%左右的孔隙从小于1000nm孔径发展扩大到10000~50000nm孔径是塔砖材料孔隙率增大的主要表现形式。因此,预防小孔径孔隙(小于1000nm)在气候影响下发展扩大的防治措施应该成为中国古代砖塔保护工作的研究重点。同时,对因塔砖材料性能劣化而产生的古塔塔体的表观特征进行了分析,分析结果有利于中国古代砖塔的保护。 相似文献
45.
The aim of this work is to verify or refute hypothesis of existence of basic/universal glass batch: quartz sand: potash: limestone, at a ratio of 2: 1: 1 used in Bohemian glass production since the middle ages onwards and to simulate the preparation of a potassium glass type with the composition used in medieval Bohemia. The chemical composition of Bohemian glass, which incorporated in the proposed glass batch for glassmaking on a laboratory scale, was evaluated by (a) findings directly related to glassmaking (samples from glasswork in Moldava dating back to the 15th century) and (b) information from publications.Experimentally produced glasses for the present paper were prepared from raw materials such as ash, leached ash, potash, limestone and quartz sand. The plant raw materials (spruce, beech and bracken ashes, raw and refined potash) were treated and prepared by methods similar to the production procedures used in the pre-industrial era.The main contrast was found in the CaO/K2O weight ratio, which was determined in glasses that were characteristic of given periods. While this ratio was often below 1 in glasses of the 15th century, it reached values above 1 in glasses at the turn of the 16th-17th centuries. This result may indicate that the composition of the glass batch had changed.The results of the present study reject the current scholarly work dealing with glass batch composition during the 14th-17th centuries and confirm that glass produced in some Bohemian medieval glassworks could have been melted from a batch that included plant ash, making the use of limestone unnecessary. The traditional suggestion of the exact ratios of raw materials, often cited in historical literature, seems to be impossible. The glassmakers had to react to the variable composition of the raw materials, especially plant ash. 相似文献
46.
47.
《Asian Population Studies》2013,9(1):50-77
Limited studies document the fertility changes in Central Asia. Using survey and official data, this study describes the fertility changes since 1980 in Kazakhstan, the Kyrgyz Republic, and Uzbekistan. I first consider the swift decline in fertility in the 1980s and 1990s through the analysis of Synthetic Parity Progression Ratios (SPPRs). SPPRs show that women still have at least one child despite economic difficulties and that the end of communism affected more the transition to higher-order births. These results are however influenced by economic and demographic factors specific to each country. I investigate then the fertility upturn that is observed since the early 2000s—an issue neglected so far by demographers. Results from the analysis of official and household data show that in each country, the recent fertility increase resulted from the increase of distinct birth orders and was concentrated in specific ethnic groups. 相似文献
48.
D. Adan-Bayewitz A. Karasik U. Smilansky F. Asaro R.D. Giauque R. Lavidor 《Journal of archaeological science》2009,36(11):2517-2530
Cooking pots and bowls from two production locations ca. 200 m from each other at the rural settlement of Kefar Hananya in Roman Galilee were compared employing chemical element composition and vessel-shape analyses. Splits of each pulverized sample, all of which were taken from ceramic wasters, were analyzed by both instrumental neutron activation and high-precision X-ray fluorescence analyses, and computerized vessel-shape analysis was employed for morphological analysis of the same vessel forms from each location. Several statistical techniques (bivariate plots, principal component analysis, cluster analysis and discriminant analysis) were used for analyzing the resultant data. It was found that both the cooking pots and bowls made at each location could be distinguished by employing either chemical composition or morphological analysis. The implications of this work, with regard to investigating both production and consumption sites, and for pottery provenance studies, are discussed. The findings suggest that these analytical techniques can be useful as an aid for chronological differentiations of archaeological pottery. 相似文献
49.
一批中国古代镶嵌玻璃珠化学成分的检测报告 总被引:4,自引:0,他引:4
结合外束质子激发X荧光(proton induced X-ray emission,PIXE)和能量色散X射线荧光(energy dispersive X-ray emission,EDXRF)分析技术,对中国新疆、湖北、四川、广东出土的古代镶嵌玻璃珠的化学成分进行了检测.结果表明:新疆拜城克孜尔墓地出土的西周-春秋时期镶嵌玻璃珠为CaO-MgO-SiO2玻璃,战国时期中国境内的PbO-BaO-SiO2和Na2O-CaO-SiO2镶嵌玻璃珠是同时存在的.本文亦对相关问题进行了一些讨论,并提出了部分今后的工作建议. 相似文献
50.
Does technology shape music? Aesthetics of assembly at the beginning of the 20th century. This article deals with the relationship between assembly in production technology and similar processes in musical composition. Can composers like Eric Satie, Igor Strawinsky or George Antheil, who used assembly methods in some of their compositions, be called assemblers? The authors point out that all three composers used assembly methods in different ways and with different purposes. Applying a theoretical approach inspired by media studies they come to the conclusion that the conditions under which musical works using assembly methods are shaped do not originate in technology but in the aesthetic convictions of the composer. Apart from assembly methods there are many other compositional principles the composer relies on. Technology may inspire music but does not determine the musical outcome. 相似文献