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81.
Abstract

Semi-arid landscapes are vulnerable to cultivation, overgrazing and climate variability, although it is difficult to identify the relative significance of these three factors. In the South African Karoo, the ‘desertification debate' seeks to explain a change to more shrubby vegetation in heavily grazed areas. We examine these issues in catchments where farm reservoirs provide sediment stores with 137Cs, 210Pb, geochemical and mineral magnetic signatures. Rainfall data and stocking numbers are reported and current erosion rates are estimated. Sediment accumulation in the reservoirs increases between 1935 and 1940, probably due to rises in the frequency of rainfall events of >25mm day. Significant increases in sedimentation rates (×8) occur during rain-fed wheat cultivation. In an uncultivated catchment, sediment yields remain relatively high and reflect increases in erosion from hillslopes, colluvial storage, and cultivated land sources. Gully systems have acted as transport routes rather than sediment sources over the last ~70 years. Badland erosion rates average ca. 50t ha?1 yr?1. At Ganora, their development in the 1920s strongly influences peak sedimentation between 1970 and 1980. Any delay between badland initiation and increased sediment yield appears to be a function of landscape connectivity. Recovery following disturbance is occurring slowly and is likely to take >100 years. De-stocking and better management systems are reducing erosion rates but may be offset by increases in rainfall intensity.  相似文献   
82.
Nihewan and Zhoukoudian are important areas where early humans and cultures originated and reproduced in northern China and even East Asia. Geologically, both site groups belong to the Haihe River valley; chronologically, the Nihewan sites date to ca. 1.7 million years ago, and the Zhoukoudian sites date to ca. 0.5 million years ago; and culturally, both are dominated by the small-flake-tool culture. Thus, it is speculated that the early culture in the Zhoukoudian sites came from the migrants from the Nihewan Basin who facilitated cultural diffusion in the area; in turn, it also affected the culture in the Nihewan area during the subsequent development. This paper proposes the development path of the Paleolithic culture in northern China, that is, early humans in this region roughly experienced three stages of subsistence from lake-dependent to cave-dependent and then to river-dependent.  相似文献   
83.
Much fuss has been made of the “spatial turn” in recent years, across a range of disciplines. It is hard to know if the attention has been warranted. A confusion of terms has been used—such as space, place, spatiality, location—and each has signified a cluster of often contradictory and confusing meanings. This phenomenon is common to a range of disciplines in the humanities. This means, first, that it is not always easy to recognize what (if anything) is being discussed under the rubric of space, and second, that over‐extended uses of the cultural turn have stymied meaningful engagement with (or even a language of) materiality in discussions of space. This article shows how materiality has been marginalized both by a casual vocabulary and a vigorous a priori epistemological holism on the part of scholars, and how the spatial turn has been too closely linked to the cultural turn to allow it to develop its fullest explanatory potential. It demonstrates how historians might profitably theorize the significance of place and space in their work (borrowing techniques from geographers and anthropologists, and referring to the phenomenological tradition), and sets out some challenges for using space more effectively in explanatory systems. Inspired by environmental history, sociology, and science and technology studies, I propose a way of establishing space as different from conventional historical handling of materiality, and end by identifying some methodological problems that need to be solved if we are to proceed on a surer footing.  相似文献   
84.
Abstract

Over the past few decades, the archaeological community has been moving away from the more traditional methods of excavation and recovery of underwater cultural heritage towards a less intrusive management approach, essentially involving the preservation of sites in situ. This trend has been politically galvanized in Article 2, point 5 of the Convention on the Protection of the Underwater Cultural Heritage (), which states that ‘The preservation in-situ of underwater cultural heritage shall be considered as the ?rst option before allowing or engaging in any activities directed at this heritage’. Over the years, a number of different remediation strategies have been utilized in order to protect underwater cultural heritage sites in situ, and most of the techniques or combinations thereof involve reburial of sites. Reburial may be an appropriate means of stabilizing and decreasing the deterioration rate of a site, however, there needs to be a holistic approach to the study of the environment, before and after reburial, to gain a full understanding of the changes that are occurring on the site and determine the effectiveness of the technique.

In early 2000, the James Matthews, a copper-sheathed, wooden-hulled vessel wrecked in 1841 south of Fremantle, Western Australia, was identi?ed as being under considerable threat from increased site exposure due to a combination of natural near-shore sedimentary processes and industrial activity in the immediate area. An extensive on-site conservation survey was carried out to establish the state of preservation of the wreck and provide information regarding the physico-chemical and biological nature of the environment prior to the implementation of any mitigation strategy. In 2003 it was con?rmed that further exposure of the site was occurring and devising a management plan was of paramount importance.

Since this time a number of different reburial techniques have been trialled on the site and these include sand bags of differing material composition, polymeric shade cloth, arti?cial sea grass mats made from polyvinyl chloride bunting, and the use of interlocking medium density polyethylene ‘crash barrier’ units in a cofferdam arrangement to con?ne deposited sand. The geological, physico-chemical, and microbiological changes in the burial environments have been monitored over this time. Furthermore, the broader scale, near-shore sedimentary processes affecting the site are being assessed in order to establish the reasons behind the continuing sediment loss. In situ preservation of the iron ?ttings by cathodic protection has also been included in these ?eld trials. In this paper the results from these experiments will be summarized. This information will be used to ?nalize the design of the full-scale in situ preservation strategy for the site and assist in establishing a post-reburial monitoring programme that will measure the success of the adopted remediation technique.  相似文献   
85.
Abstract

The aim of this paper is to discuss the long-term management of marine historic environment archives, focusing on the comparison of English Heritage’s National Record of the Historic Environment (NRHE) with the United Kingdom Hydrographic Office (UKHO) as case studies.

Within marine (and terrestrial) contexts, archaeological archives are unique records of survey, excavation, and associated research of the historic environment. They are a resource which allows understanding of the human past to be developed, reviewed, and reinterpreted as new data is gathered. As such, they are significant for research, development-led studies, education, outreach, and public enjoyment. At a time when there is a significant focus on data from the marine environment, both within the UK and more widely across Europe, this paper puts forward some initial recommendations to enable further interoperability between these two key national datasets.

Analysis of these datasets highlighted some interesting points, including the quantification and qualification of the scale of discrepancies between data providers (NRHE and UKHO), and how these can be overcome to allow comprehensive, reliable, and accessible data on which to base long-term planning, decision-making, and resource management. This will ensure a consistent approach, enabling the successful long-term management of historic environment archives, and making historic environment data readily accessible to the wider public.  相似文献   
86.
陈文成  郑伟民 《人文地理》2010,25(2):110-115
构建福建省地级市投资环境竞争力评价指标体系,为GIS环境地级市多边形的主要属性,以2000-2007年福建统计年鉴为主要数据源,建立时态空间数据库。通过"时空同时归一"的指标变换方法定义投资环境相对竞争力,使不同指标"等价"与引入时空统一标准,选择时间序列、截面权变显著的经因子分析确定权矩阵,进行变权法三维评价,利用序列快照模型表达、逼近福建省投资环境竞争力空间过程,通过基于数据的空间过程因子识别技术,进行驱动因素分析,为优化福建省投资环境提供调控依据。  相似文献   
87.
从区位功能和投资环境看南京的发展走向   总被引:5,自引:1,他引:4  
南京不仅是江苏省的政治、经济、文化中心,也是长江下游仅次于上海的第二大经济中心,并成为长江流域四大区域经济的中心之一,其超越省际的区域经济中心的位势正逐步得到加强。本文着重从空间区位和功能作用的角度分析南京的投资环境,进而对南京大都市的重点投资产业和空间发展前景作一些探讨。  相似文献   
88.
This paper outlines the environmental history of the Tigrean Plateau (northern Ethiopia) during the Holocene, based on the available geomorphological, palynological, archaeological, and historical evidence. At present, it seems that (1) the plateau experienced a more humid climate with a denser vegetation cover during the Early Holocene; (2) Soil erosion due to clearing vegetation began in the Middle Holocene; (3) agricultural activity was intensified in the Late Holocene, as a consequence of the rise of a state; (4) demographic pressure increased from the early first millennium BC to the mid–first millennium AD, causing soil erosion; (5) environmental degradation and demographic decline occurred in the late first millennium AD; (6) the vegetation cover was regenerated in the early second millennium AD; and (7) progressive vegetation clearance started again in the second half of the second millennium AD.Cet article trace l'histoire ambiante du Plateau Tigréen dans l'Holocène en utilisant les données géomorphologiques, palynologiques, archéologiques et historiques. Il semble que (1) dans l'Holocène ancien le plateau était caractérisé par une phase humide avec une dense végétation; (2) l'érosion causée par l'abbattage de la végétation commen¸a dans l'Holocène moyen; (3) l'activité agricole s'inténsifia à la fin de l'Holocène, par conséquence de l'essor d'un état; (4) la pression démographique augmenta de plus en plus du début du premier millénaire av. J.-Ch. à la moitié du premier millénaire ap. J.-Ch.; (5) la dégradation ambiante et la diminution démographique se vérifièrent à la fin du premier millénaire ap. J.-Ch.; (6) une régéneration de la vegetation se vérifia au début du seconde millénaire ap. J.-Ch.; et (7) l'abbatage de la végétation recommen¸a dans la seconde moitié du seconde millénaire ap. J.-Ch.  相似文献   
89.
岭南文化区域系统分析   总被引:4,自引:0,他引:4  
从整体的发展历程来看,岭南文化是中华民族文化中最具特色、最活跃的区域文化之一。岭南文化区域在历史上曾是中国经济文化最发达的地区之一;本世纪末的改革开放20年来,岭南地区成了一块经济发展的热土,使岭南文化一跃成为推动中国经济发展的高势能文化之一。岭南文化在其孕育、成长、定型和演变过程当中受自然与社会环境的影响很大,构成了其特有的文化整合与演变模式。本文从区域系统分析的角度对岭南文化进行初步研究,得出结论:(1)岭南文化是山水型的实用文化;(2)岭南文化是开放性和兼容性极强的区域文化;(3)重实践,讲创新,少说多干是岭南文化的精髓;(4)岭南文化系统在发展变化过程中,形成了独特的南国文化景观。  相似文献   
90.
谢理  邓毛颖 《人文地理》2000,15(5):14-18
城市快速轨道交通建设对任何一个城市来说都是巨大的经济负担,然而在适当的地段采用高架形式以节省资金,却常常不为人们所接受,主要在于其对城市环境、景观的影响方面。本文以广州市地铁二号线为例,对从快速轨道的高架线环境和景观影响因素进行分析,阐明了城市快速轨道采用高架线不仅仅是由于经济方面的原因,它对城市景观也是一种强化,它可以促进城市早日形成快轨交通网络系统,对解决城市交通、环境问题更加有利,而它的环境影响也可以控制在人们接受的水平等观点。并提出解决快轨交通高架线对城市环境和城市景观造成影响的方法和措施。  相似文献   
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