全文获取类型
收费全文 | 825篇 |
免费 | 46篇 |
出版年
2024年 | 4篇 |
2023年 | 10篇 |
2021年 | 6篇 |
2020年 | 21篇 |
2019年 | 23篇 |
2018年 | 59篇 |
2017年 | 52篇 |
2016年 | 43篇 |
2015年 | 35篇 |
2014年 | 33篇 |
2013年 | 178篇 |
2012年 | 23篇 |
2011年 | 28篇 |
2010年 | 34篇 |
2009年 | 22篇 |
2008年 | 16篇 |
2007年 | 15篇 |
2006年 | 12篇 |
2005年 | 8篇 |
2004年 | 4篇 |
2003年 | 14篇 |
2002年 | 21篇 |
2001年 | 11篇 |
2000年 | 16篇 |
1999年 | 43篇 |
1998年 | 30篇 |
1997年 | 12篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1994年 | 5篇 |
1993年 | 2篇 |
1992年 | 5篇 |
1991年 | 5篇 |
1990年 | 3篇 |
1989年 | 6篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1984年 | 3篇 |
1983年 | 7篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 4篇 |
1977年 | 6篇 |
1975年 | 3篇 |
1966年 | 1篇 |
1953年 | 1篇 |
1950年 | 2篇 |
排序方式: 共有871条查询结果,搜索用时 15 毫秒
1.
Die Auswirkungen des Einsatzes
moderner Informationsund Kommunikationstechnologien (IuK) werden
oftmals unter dem Schlagwort der Globalisierung zusammengefaßt.
IuK-Technologien stellen die technischen Voraussetzungen
beispielsweise für die weitgehende Vernetzung von Unternehmen,
für neue Formen der Arbeitsteilung und
-kooperation.Im Fokus der wissenschaftlichen
Diskussion um E-Commerce stehen Veränderungen auf globaler
Ebene, die Frage nach den möglichen, raumwirksamen Veränderungen
in den Regionen wird dagegen nur wenig diskutiert. Was aber
bedeutet der Einsatz von E-Commerce konkret für Absatzmärkte,
Kunden- und Lieferantenbeziehungen auf der regionalen Ebene?
Besteht die Gefahr einer Schwächung insbesondere der
mittelständischen, meist regional verankerten Betriebe oder
bietet E-Commerce gerade für die kleineren und mittleren
Unternehmen (KMU) die Chance eines Innovationsschubs? Ein Blick
auf die regionale Ebene zeigt, daß hier zahlreiche
Förderaktivitäten unternommen werden. Dies wirft Fragen auf:
Welche Strategien sind bei dieser Förderung erkennbar? Wie geht
die traditionelle Wirtschaftsförderung mit diesem für sie neuen
Thema um?
相似文献
相似文献
2.
J.M.P. Cabral M.A. Gouveia A.M. Alarcão J. Alarcao 《Journal of archaeological science》1983,10(1):61-70
The concentrations of two major elements and thirteen trace elements in 73 selected sherds of fine grey ware from the Iron Age and Roman period, excavated at Conimbriga, Santa Olaia and Tavarede, Portugal, were determined by instrumental neutron activation analysis. These concentrations were used to calculate distance matrices which were then subjected to cluster analysis employing SAHN and k-means methods, as well as to principal components analysis, to group the sherds according to the overall similarity of their compositional characteristics. The results showed that equivalent groupings appeared regardless of the taxonomic method used. Two major clusters were recognized corresponding to two different sites, namely Conimbriga and Santa Olaia, suggesting that the ceramics from these sites were made locally. No significant differences in compositional patterns were observed between iron age and roman sherds from Conimbriga. 相似文献
3.
4.
5.
Philip De Barros 《African Archaeological Review》1988,6(1):91-113
Numerous scholars have outlined what they believed to be the consequences of the advent of iron technology in sub-Saharan Africa: increased food production using more efficient bush clearing tools; increased population densities; larger and more stable communities; increased trade, specialization and social differentiation; and the embryonic rise of modern politics. (Davidson 1974.) However, little has been demonstrated in the field.A regional study of the Bassar iron industry of northern Togo has shown that the rise of large-scale iron production may lead to higher population densities, larger and more stable communities, a more aggregated settlement pattern in the ore zone, and increased craft specialization and trade. However, it does not necessarily result in a significant increase in the degree of political centralization. The Bassar data also suggest that even the appearance of relatively small scale iron production may generate similar trends, albeit at more modest levels.
Résumé De nombreux auteurs ont décrit ce qu'ils proposent d'avoir été les conséquences de l'adoption de la technologie de fer dans l'Afrique au sud du Sahara: augmentation de la production de nourriture à l'aide des outils plus efficaces pour débroussailler le paysage; augmentation des densités de population; communautés plus grandes et plus stables; croissance de la commerce, de la specialisation artisanale et de la differentiation sociale; et naissance embryonique de la politique moderne (Davidson 1974). Cependant il n 'y a que très peu de ce schéma qui a été validé par les recherches sur le terrain.Une étude régionale de l'industrie du fer des Bassar du nord de Togo a montré que l'essor de la production de fer à grande échelle peut aboutir à des densités de population plus hauts, des communautés plus grands et plus stables, une répartition de l'habitat plus agrégée dans la zone des minerais de fer, et l'augmentation de la specialisation artisanale et du commerce. Cependant il n'aboutit pas obligatoirement à une centralisation importante au niveau politique. Les résultats fournis par cette étude des Bassar nous amènt à proposer aussi que même l'apparition de la production modeste de fer peut donner naissance à des développements comparables, mais d'un ampleur plus restreint.相似文献
6.
Eloise Quiñones Keber 《Colonial Latin American Review》1992,1(1-2):223-239
Aztecs: An Interpretation. By INGA CLENDINNEN. New York: Cambridge University Press, 1991. Pp. xiii, 398.
The Slippery Earth: Nahua‐christian Moral Dialogue in Sixteenth‐century Mexico. By LOUISE M. BURKHART. Tucson: The University of Arizona Press, 1989. Pp. xii, 242. 相似文献
7.
8.
Lorena Grana Sonia Lanzelotti Victoria Arévalo Alvaro Yamil Tesio Nora Irene Maidana 《Archaeometry》2023,65(2):391-408
In the Andes, there are several pre-Hispanic irrigation networks with structures destined for water storage. However, it has not been widely discussed in archaeological research. This is probably due to their being difficult to identify. The aim of this study is to explore the use of diatom assemblage analysis as a methodological tool suitable to help in the identification and characterization of these ancient hydraulic structures. We analyzed two archaeological structures interpreted as water reservoirs from north-western Argentina (EH1 in Antofagasta de la Sierra and U-88R1 in Yocavil) and compared them to current reservoirs. The diatom species composition and the changes in the dominant ecological groups in the studied structures highlight different periods of hydraulic behavior. EH1 contained and stored water, but there were periods of time in which there was a lack of use or abandonment of the structure. However, the U88-R1 structure does not have diatom evidence of containing standing water for a prolonged time but presence of wet soils. Thus, the structure could have been used for other water management strategies. The results show that diatom analysis is a methodological tool with a high potential to study ancestral hydrotechnologies. 相似文献
9.
Darío Alejandro Ramirez María José Herrera-Soto Josefina González Andreu Francisca Santana-Sagredo Mauricio Uribe Rodríguez Rodrigo Nores 《Archaeometry》2023,65(5):1073-1089
Faunal remains from archeological sites worldwide, especially feces and regurgitated pellets, are usually subjected to paleoparasitological examination, allowing the identification of past animal parasites. In this study, we analyzed 10 samples of South American camelid dung, which played an important role for the ancient human groups in the South-Central Andes, dated between 341 and 1635 calCE, from the Iluga Túmulos site (Pampa del Tamarugal, Tarapacá region, Atacama Desert, Chile). Microscopy examination revealed parasite remains in seven samples, in which oocysts of Eimeria macusaniensis and eggs of Lamanema chavezi/Nematodirus lamae, Trichuris sp., Moniezia sp., capillariids, strongylids, and unidentified nematodes were found. Although some of these species pose a potential health risk to camelids, most are not considered to be of major zoonotic importance, which could explain the absence of these parasites on human coprolites from this site analyzed previously. This first paleoparasitological study on camelid fecal remains from northern Chile sheds light on the occurrence of gastrointestinal parasites and its relationship with Andean ancient human populations and the environment. 相似文献
10.
Juan Luis Gómez-Reino Santiago Lago-Peñas Jorge Martinez-Vazquez 《Journal of regional science》2023,63(4):793-819
The standard theory of optimal jurisdictional size hinges on the existence of economies of scale in the provision of local public goods and services. However, despite its relevance for forced local amalgamation programs and related policies, the empirical evidence on the existence of such economies of scale remains elusive. The main goal of this paper is to produce an updated and comprehensive quantitative review of the existence of economies of scale in the provision of local public goods using a meta-analysis approach to systematize the wide range of empirical approaches and modeling frameworks found in the previous literature. Our analysis confirms the presence of moderately increasing to constant returns to scale in the provision of local services with no reduction in the average costs of production in the delivery of most local public services beyond a certain, modest jurisdictional size, which many studies have estimated at 10,000 residents. Also, the potential for economies of scale differs at least across three traditional services: education, water and sanitation, and garbage collection, being highest for education and lowest for garbage collection. Our analysis also offers guidelines for future empirical research in this area. Physical output and production cost data should be used, together with translog specifications for the modeling of cost functions. Last, we find evidence that the determinants of output cost elasticity include bidirectional publication bias and population density but do not include the presence or absence of modern “lean” production technologies or the (perceived) capital intensity of the sector, contrary to conventional wisdom. These findings have significant policy implications for countries considering jurisdictional consolidation programs. 相似文献