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41.
Little is known of hard-rock coastal landsliding in Scotland. We identify 128 individual coastal landslides or landslide complexes >50 m wide along the coasts of Shetland. Most are apparently translational slides characterized by headscarps, displaced blocks and/or debris runout, but 13 deep-seated failures with tension cracks up to 200 m inland from cliff crests were also identified. Thirty-one sites exhibit evidence of at least localized recent activity. Landslide distribution is primarily determined by the distribution of coastal cliffs >30 m high, and they are preferentially developed on metasedimentary rocks. Analysis of 16 landslides on Fetlar (NE Shetland) indicates that most are translational dip-slip failures; 3 represent deep-seated failures and several exhibit active frontal erosion attributable to basal sapping by storm waves. As these landslides terminate in shallow water, failure was probably initiated when rising sea level resulted in footslope erosion and upslope propagation of instability, causing downslope displacement of landslide blocks on upper slopes. 10Be exposure dating of two headscarps yielded ages of 4.8?±?0.2 ka and 4.4?±?0.2 ka, consistent with the onset of footslope erosion as sea level rose. Our results suggest that landslides have played a hitherto undocumented but important role in retreat of cliffed coastlines in Scotland.  相似文献   
42.
Evidence of agricultural activity in Scotland during the Bronze Age is sparse. A bank system of that date, covered by a deep peat accumulation, in Argyllshire, Scotland has preserved a podzolic palaeosol. Palynological investigation of the palaeosol allows a consideration of potential prehistoric land use. The existence of a well developed iron pan in the palaeosol divides the soil pollen into two contrasting groups, suggesting two quite distinctive periods of land use. Also discussed are the problems which the processes of podzolization cause pollen analysts, the dating of buried soils and the possibility of periodicity in pollen movement through a soil.  相似文献   
43.
In the early 1900s shells of a large freshwater mussel, Margaritifera auricularia (Spengler), were discovered in calcreted gravel dredged from the channel of the Thames at several sites between Mortlake and Battersea in west London. These specimens were said to have been associated with Neolithic polished stone axes, supposedly as food remains. M. auricularia is now extinct in Britain, but it has been reported living in several large rivers in southern Europe although apparently not in recent years. Three radiocarbon dates of 4140±50, 4340±45 and 4860±40 bp have been obtained from Thames specimens, supporting a Neolithic age for these shells. The theory that the shells represent debris from imported human food is discounted and it is considered more likely that M. auricularia was actually living in the Thames in Neolithic times. Its extinction in Britain should be seen as part of a general recession during the Post-glacial, as revealed by fossil occurrences to the north and east of its present-day range.  相似文献   
44.
Over a period of some 100 years it has gradually been accepted that the human skeletal remains found in the late nineteenth century in ancient gravels at Galley Hill, Kent are not those of early man, but are of much more recent date. This conclusion was finally verified by means of relative (N, F) and absolute (14C) dating. Here we present the results of further analysis of the remains from Galley Hill for their uranium content by a method having general application to the relative dating of fossil human and other mammalian bone.  相似文献   
45.
There is an increasing use of palynological data to infer prehistoric agricultural activity. The uncritical acceptance of the technique of pollen analysis by archaeologists and palynologists is questioned. Attention is focussed upon the nature of clearance activity and problems of its inference from pollen spectra; the spatial distribution of palaeoenvironmental sites; and the proximity of such sites to those of prehistoric activity. The resolution apparent in peat and lake sediment pollen profiles together with problems of dating and temporal inference, are examined. In response to a perceived lack of formalization in palynological research, some simple models of clearance activity are presented. The complexity involved in environmental reconstruction is emphasized by reference to the use of supplementary data to augment the orthodox pollen record.  相似文献   
46.
The construction date of the medieval manor house at Clevedon Court has long been said to be ‘c. 1320’, but no explanation or justification has ever been published. Stylistic, documentary and archaeological evidence is assembled to show that, following three distinct building phases, the house was completed during the decade ending in 1320. Analysis of the development of reticulated tracery helps to determine the date of the iconic chapel window. Other elements of the medieval house are considered and explained.  相似文献   
47.
The thermoluminescence dating method was applied to 77 heated flints from the Mousterian layers of Hayonim Cave in order to provide a precise TL-based chronology for this important Levantine sequence. A detailed dosimetric study was performed by using 76 dosimeter capsules and revealed strong spatial dose-rate variations. In parallel, Fourier transform infrared spectrometry enabled the identification of various mineral assemblages in the sediments of the cave and to localize the boundaries of these assemblages. By comparing these two data sets, it is shown that low dose-rate values (∼500 μGy/a) are systematically recorded in areas where the calcite-dahllite (CD) assemblage is preserved, whereas higher values (up to 1300 μGy/a) are associated with the leucophosphite, montgomeryite, variscite and siliceous aggregates (LMVS) assemblage. The dosimetric and mineralogical information was combined in order to assess, where possible, the dose-rate experienced by each flint during its burial. Some of the flint samples analyzed were too close to mineral assemblage boundaries and were therefore discarded. This rigorous selection led to TL ages ranging from 230 to 140 ka for the lower part of the Mousterian sequence (layers F and Lower E), which contains lithic industries characterized by blade production using the laminar method.  相似文献   
48.
More than 40 logboats are known from the Czech Republic, and at least 20 are preserved in repositories or regional museums (seven in Moravia, 13 in Bohemia). Two further vessels remain in situ. Many logboats are known from neighbouring countries, but until recently vessels from the Czech Republic have not attracted the same research interest. Only five Czech vessels (two from Bohemia and three from Moravia) have been dated by absolute methods. Several more have been assigned tentative dates on the basis of context or close similarity to other dated vessels. This article presents a summary of current evidence. © 2009 The Author  相似文献   
49.
Under certain environmental conditions, post-depositional diagenetic loss of bone collagen can severely reduce the number of bones from a particular archaeological site that are suitable for stable isotopic analysis or radiocarbon dating. This study examined nearly 300 bones from 12 archaeological sites across southern England known to yield poor or variable preservation to try to identify one, or more, pre-screening technique(s) that would indicate suitable collagen preservation for radiocarbon dating. The most reliable method was shown to be the percent nitrogen (%N) of whole bone powder, which has an 84% chance of successfully predicting whether or not a bone will yield sufficient (i.e. >1% weight) collagen for dating.  相似文献   
50.
This paper presents new AMS radiocarbon dating results of six ungulate bones from the current excavation of Isturitz Cave, France, layer C 4c4. The assemblage from this layer exhibits a suite of traits closely aligned with the Early Aurignacian, but with some aspects that bear strong similarities with the Protoaurignacian, with possible in situ technological transformation. Accurate and precise dating of the late Middle Palaeolithic and the early Upper Palaeolithic periods is critical to our understanding of the possible relationship between final Neanderthals and early modern humans in Europe. As such, a rigorous set of sample selection and evaluation protocols was developed and used in this research. Among these, only cutmarked bones were selected and a total of 31 targets were made, giving a weighted average of 37,180 ± 420 BP for this assemblage and providing a terminus ante quem for the ornaments, decorated artefact and amber pendants beneath it. The implications and importance of these results to debates concerning the chronological relationship between the Châtelperronian, Protoaurignacian and Early Aurignacian and associated debates regarding hominin dispersal, interaction and the timing of technical and cultural innovations are discussed.  相似文献   
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