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41.
Conditions in which thermal fractures occur are explored experimentally, and the results are used to assess heat treatment strategies. We conclude that no single ‘critical temperature’ for thermal fracturing or heat treatment can be specified for any particular raw material, as has so often been attempted, because threshold temperatures exist in relationship to specimen sizes. Our experiments show that smaller specimens are resilient to greater ranges of temperature fluctuations than larger ones, and that by manufacturing/selecting specimens of smaller sizes there is more potential to heat them rapidly and to higher temperatures without producing thermal fractures. We hypothesize a continuum of heat treating strategies between a ‘slow and steady’ strategy, which has overwhelmingly dominated past experimental designs, and a ‘fast’ strategy, which has received much less attention. The paper discusses the economic and technological contexts to which different heat treating strategies might be suited. 相似文献
42.
The identification of projectile impact traces on archaeological faunal remains is an important issue for understanding prehistoric hunting behavior, especially in the Paleolithic and Mesolithic. From the beginning of the Upper Paleolithic in Europe, and earlier in Africa, projectiles tipped with osseous points were of great importance for subsistence; but thus far, no specific experimental reference has been developed to help identify the traces left by these points. In 2003 and 2004 two series of projectile experiments with antler points of Magdalenian design were organized, involving two ox calves and two female fallow deer as targets for bow and spearthrower shooting. The subsequent study demonstrates that positive identifications of impact traces left by osseous points can be made. The observation of 127 impact traces allowed us to distinguish three main types of traces: notches, punctures and perforations. The relationships between the nature of the impact traces and the (i) target species, (ii) characteristics of the impacted bones, and (iii) type of weapon are presented. Synthesized results are then discussed within the context of the European Upper Paleolithic and Mesolithic. 相似文献
43.
Ignacio Clemente Conte Facundo Gómez Romero 《International Journal of Historical Archaeology》2008,12(3):248-262
This paper presents the results of a microscopic analysis conducted on supposedly retouched glass fragments that were likely used as tools. The pieces were recovered in a series of excavations performed at the historical site of Fortlet Miñana (1860–1869), a military settlement used during the war against the Indians on the southern border of Buenos Aires province, Argentina. The use of glass as raw material in archaeological sites of the historic period has frequently been reported in the Pampas and Patagonian regions. In this paper we present a review of ethnohistoric and ethnographic sources concerning the use of glass side scrapers, end scrapers, and arrowheads by aboriginal groups throughout the world. In order to perform the analysis, the glass fragments from Fortlet Miñana were compared to a series of experimental pieces on which traces of deliberate use on two kinds of raw material, wood and hide, were identified. The experimental approach and the microscopic analysis demonstrate that the retouched glass fragments recovered at Fortlet Miñana were not used as tools. Therefore, we conclude that microscopic analysis is of significant use to all researchers working with materials of this kind. 相似文献
44.
农村新型合作医疗制度,是由政府组织、引导和支持农民自愿参加,由个人、集体和政府多方筹资并以大病统筹为主的农民医疗互助共济制度。为了更加有效地解决农民“看病难、看病贵”问题,西宁市政府应积极履行社会管理和公共服务职能,切实建立农村新型合作医疗科学高效的筹资机制、运行机制、监督机制和规范机制。 相似文献
45.
1959年5月,为适应防疫的需要并迎接新中国成立10周年,中华人民共和国卫生部、中国人民解放军总后勤部卫生部和中华医学会在北京联合召开了全国急性传染病学术会议。会议贯彻中西医结合的卫生工作方针,结合时代发展需要,交流并总结了新中国成立以来医学界在防治急性传染病方面取得的成功经验,制定了8种急性传染病防治方案,对此后的传染病防治和研究起到了重要的推动作用。此次会议既为当代中国防疫史增添了浓墨重彩的一笔,同时也在我国医学发展史上具有重要意义。 相似文献
46.
Substantial damage sustained during several recent earthquakes was non structural in nature. The economic consequence in terms of non structural component damage far exceeded the structural damage. Currently, there are several analytical studies that address the interaction between non structural components or Secondary systems (S-systems) and the main supporting structure or Primary system (P-system). Only a few of these analytical approaches have been proposed to evaluate and characterize the response of the S-systems attached to torsionally coupled P-systems. In addition, the experimental verification for the analytical approaches is scarce. In the current study, the results and observations of an experimental research program conducted to characterize the behavior of both stiffness eccentric and mass eccentric torsionally coupled Primary-Secondary systems (PS-systems) are presented. From this experimental investigation it was found that the torsional yielding of the primary system has significant implications on the deamplification of near tuned secondary system response. The location of the S-system mounted on the P-system affects the peak response amplification, and interaction with the coupled P-system. 相似文献
47.
In this paper, the results of an experimental program dealing with the ultimate behavior of bolted beam-to-column connections under cyclic actions are presented. The design criteria adopted for tested specimens are discussed in detail, aiming to point out how the ultimate behavior can be governed by properly strengthening the components for which yielding has to be prevented. To this scope, the component approach is adopted as a design tool for component hierarchy criteria. The aim of the paper is the investigation of the actual possibility of extending the component approach to the prediction of the cyclic response of beam-to-column joints. To this scope, the attention has been focused on the possibility to evaluate the overall energy dissipation capacity starting from the energy dissipation of the single joint components, provided that they are properly identified and their cyclic behavior is properly measured. 相似文献
48.
Giampaolo Piga Giuliana Solinas T.J.U. Thompson Antonio Brunetti Assumpció Malgosa Stefano Enzo 《Journal of archaeological science》2013
The possibility of determining the human or animal origin of bones from the lattice parameters of their inorganic bioapatite phase, when subjected to a high temperature treatment using the powder X-ray diffraction (XRD) technique, has been explored on a wide number of specimens. Forty-two animal bones were treated in a furnace at 1100 °C for 36 min and compared to 53 cremated human bones from a range of ancient necropolises. The X-ray diffraction patterns of bioapatite were simulated using both monoclinic P21/b and hexagonal P63/m structures to verify any occurrence of phase transformation and any difference in the lattice parameters due to the model. It was determined that the differences between the a-axis and c-axis of the monoclinic and hexagonal lattice were unimportant. Some outlying values were revealed to be caused by the presence of chlorine ions diffused into the apatite structure increasing its average unit cell values. Nevertheless, our results clearly show that in terms of lattice parameters the variability of human specimens are completely overlapped by the non-human variability making the use of XRD in order to distinguish animal from human bones questionable. 相似文献
49.
Jean-Marc Pétillon Olivier Bignon Pierre Bodu Pierre Cattelain Grégory Debout Mathieu Langlais Véronique Laroulandie Hugues Plisson Boris Valentin 《Journal of archaeological science》2011
The technology of the European Upper Palaeolithic yielded abundant evidence of the use of composite projectile heads, in the form of osseous points on the side of which one or several (micro)lithic elements are attached. Yet, little experimental work has been devoted to testing and assessing the parameters of use of this type of composite tips. In this paper we present a pilot experiment with replicas of Magdalenian composite spear tips, made of an antler point with one or two rows of flint backed bladelets. Two series of replicas were manufactured after the lithic and osseous record of, respectively, the Lower Magdalenian from southwest France (c. 20–18 Ky cal BP) and the Upper Magdalenian of Pincevent in the Paris Basin (c. 15–14 Ky cal BP). The 34 experimental composite heads were hafted to spears that were then shot with a spearthrower at the carcasses of two young deer. The results provide some insight into the performance characteristics of the osseous and lithic components, both in efficiency and durability. Finally, possible improvements of the experimental protocol are discussed, as well as the implications of our results for the understanding of projectile point variability in the Upper Palaeolithic. 相似文献
50.
Metin I. Eren Stephen J. Lycett Christopher I. Roos C. Garth Sampson 《Journal of archaeological science》2011
Lithic raw material constraints are widely assumed to be a determining factor of flaked stone tool morphology, but this assumption remains largely untested. We conducted a controlled experiment to determine whether a knapper’s growing replication skills would be hindered if the toolstone used was switched from large flakes of an easily worked chert to nodules of less tractable one. Two batches of Preferential Levallois cores were knapped, an earlier series made from standardised large flakes of sediments dominated by chalcedonic quartz followed by a more challenging one using variably-shaped, cortical nodules of microcrystaline quartz that varies in the completeness of quartz replacement of calcite and dolomite. Skill level markers were designed to measure the knapper’s ability to achieve a series of set goals. These were quantified and subjected to statistical testing. In all but one test, significant increases in skill could be detected from the earlier to the later batch of reductions, despite the drop in toolstone quality. Significant improvements in the consistency of the knapper’s output could also be detected. However, the switch to a more challenging, nodular chert did require extra shaping, which resulted in more waste. This masked visible progress towards producing a less costly core. Overall, our results do not support the assumed primacy of toolstone constraints over other factors in influencing the morphology of flaked stone tools. 相似文献