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51.
This paper examines the spatial distribution of the Internet in the European regions. To achieve this aim, our analysis combines a set of non-parametric techniques proposed in the context of the economic growth literature, with various spatial econometric instruments. The results reveal that regional disparities in Internet adoption are greater than territorial inequalities in gross domestic product (GDP) per capita. In addition, our findings show that the distribution under consideration is characterized by the presence of positive spatial dependence, which implies that physically adjacent regions register a similar degree of Internet adoption. Finally, the analysis carried out allows us to assess the role played by variables such as GDP per capita, unemployment rate, stock of human capital and population density, in explaining the spatial distribution of the Internet in the European Union. 相似文献
52.
José Luis Hervás Oliver José Albors Garrigós Juan Ignacio Dalmau Porta 《European Planning Studies》2008,16(4):507-520
Classical industrial districts' literature is not focused on the role played by external ties but gives more importance to the local districts' endogenous development. Global value chains connect clusters to other external agents through external linkages and constitute a framework to analyse the complex inter-linkages between clusters and other external agents. In the field of the external ties and the global value chain approach Academia is primarily focused on the ties which link clusters in developing nations to global markets, although global value chains also consider connections between clusters in similar activities and even when both are located in developed nations. Thus, external linkages are mainly performed by multinational enterprise (MNE) affiliates which play fundamental role of knowledge diffusers and absorbers in the process of knowledge exchange throughout global value chains. The work examines the process of knowledge exchange between clusters through external ties using the global value chain approach. For this purpose, empirical work is conducted with 22 face-to-face interviews to provide a case study about a leading cluster in the global ceramic tile industry. Results show that the basic knowledge to successfully compete is locally originated, although it can be complemented with global knowledge learnt or generated in other territories. MNE affiliates bridge structural holes through external ties and reduce knowledge asymmetries within global value chains. External ties on network-based governance chains exist, matter and affect clusters allowing upgrading even between developed nations. 相似文献
53.
Efthymia Nikita David Mattingly Marta Mirazón Lahr 《Journal of Anthropological Archaeology》2012,31(4):564-572
Archaeological evidence shows that populations used to transverse the Sahara Desert throughout the Holocene despite the extreme temperatures and the rough physical terrain. The current paper examines whether the desert inhibited extended gene flow among populations by means of cranial morphology as captured by geometric morphometrics. The examined populations include the Garamantes, a group centered in Southwest Libya and largely controlling trans-Saharan trade, and various Egyptian, Tunisian and Sudanese groups dating to the Middle and Late Holocene. The results showed that most inter-population comparisons were statistically significant and therefore all populations appear more or less distant to each other. The Mahalanobis biodistance measure identified four clusters. The first consists of the Garamantes alone, the second includes the populations from Kerma and Gizeh, the third includes the Badari and Naqada, while the fourth consists of the samples from Algeria, Carthago, Soleb and Alexandria. Moreover, the distance of the Garamantes to their neighbors was significantly high and the population appeared to be an outlier. This is attributed to the location of the Garamantes at the core of the desert, indicating that, despite the archaeological evidence, the Sahara Desert posed important limitations to gene flow between the Garamantes and other North African populations. 相似文献
54.
The problems of interpretation of many overlapping species lists of fossil assemblages are discussed using the example of insect faunas from a late medieval farm site in southern Iceland. Numerical techniques were employed, principally those available within the CLUSTAN package, and it was concluded that a considerable refinement in interpretation was achieved. Such quantitative procedures are suitable for groups other than fossil insects but their employment cannot be regarded as a substitute for, rather than an adjunct to, a sound ecological approach. 相似文献
55.
Bernadett Bajnóczi Gabriella Schöll-Barna Nándor Kalicz Zsuzsanna Siklósi George H. Hourmouziadis Fotis Ifantidis Aikaterini Kyparissi-Apostolika Maria Pappa Rena Veropoulidou Christina Ziota 《Journal of archaeological science》2013,40(2):874-882
Determination of the source of Spondylus objects is essential for the interpretation of Late Neolithic exchange systems and the social role of shell ornaments. We performed stable isotope analysis combined with cathodoluminescence microscopy study on ornaments (beads, bracelets) made of Spondylus shells excavated at the Aszód-Papi földek archaeological site in Hungary, to define their origin. For comparison Spondylus finds from Neolithic sites of Greece, modern Spondylus shells from the Aegean and the Adriatic, as well as fossil Spondylus and Ostrea shells from the Carpathian Basin were also examined. Oxygen isotope composition of Spondylus finds from Aszód ranges between ?1.9 and 2.1‰ and overlaps with the oxygen isotope range of shell objects from other Neolithic sites. Modern Spondylus shells from the Aegean and the Adriatic show overlapping δ18O values with one another and with the Neolithic objects; while recent shells of the Black Sea clearly are separate isotopically from the Mediterranean ones and most of archaeological artefacts. Spondylus shells from the Aszód site have Mediterranean origin; their source can be the Aegean or the Adriatic. Based on a former strontium isotope study the use of fossil Spondylus shells is excluded as raw material used for ornaments, however, in recent years the use of fossil shells was reintroduced. The shell ornaments from Aszód-Papi földek and the fossil oyster shells collected from the Carpathian Basin exhibit some overlapping oxygen isotope values; however, cathodoluminescence microscopy indicates that the Spondylus objects retained their original aragonite material. Diagenetic calcite, which occurs typically in the fossil shells, was not detected in the ornaments suggesting that the studied objects were made of recent shells. Calcitic parts observed in some Spondylus objects are not related to fossilisation. 相似文献
56.
Denisse Argote-Espino Andrés Tejero-Andrade Gerardo Cifuentes-Nava Lizbeth Iriarte Sabrina Farías René E. Chávez Fernando López 《Journal of archaeological science》2013,40(2):1213-1223
The implementation of a 3D Electrical Resistivity Tomography (ERT-3D) survey was carried out in El Pahñú archaeological site, Hidalgo State, Central Mexico. A combination of a new ERT arrays allowed studying the subsoil beneath the Main Pyramid built near the edge of a plateau, along with another important structure (the Tecpan), which was a smaller structure that lodged the governmental council in pre-Hispanic times. The recorded information was acquired through the combination of several electrodic designs: L-Corner (LC), Equatorial (Eq), and Minimum Coupling (MC). For the Main Pyramid, the electrodes were set up around the perimeter of the structure, since they were not permitted to be inserted over the edifice, thus preventing damages to the architectonic elements. The second structure allowed inserting electrodes on selected spots within the architectonic space. The combination of the different arrays made possible the acquisition of 1204 apparent resistivities beneath the Main Pyramid and 2460 resistivity data beneath the Tecpan. The apparent resistivity data were inverted to obtain a three dimensional display of the subsoil electrical resistivity beneath the archaeological structure. The interpreted resistivity model under the Main Pyramid displayed a highly resistive structure towards its northern face that could be associated with infill. Such material was employed by the ancient constructors to level the terrain close to the edge of the cliff. Another interesting anomaly was found towards the central portion of the structure that could be associated to a foundation offer. The interpretation of data beneath the Tecpan identified the structural foundations and other interesting anomalies related to the different occupational times. The investigation supported the archaeological investigation of the site, suggesting areas of potential geological risk and of archaeological interest. For example, the Main Pyramid presents serious stability problems, indicating that the infill has weakened, producing cracks threatening long-term pyramid integrity. 相似文献
57.
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59.
Patricio López Isabel Cartajena Diego Carabias Carla Morales David Letelier Valentina Flores 《Archaeological and Anthropological Sciences》2016,8(2):277-290
Site GNL Quintero 1 (GNLQ1), located on the central coast of Chile, is the only documented Late Pleistocene drowned terrestrial site along the Pacific Coast of South America. Faunal evidence at the site is varied, and so far, remains of the following taxa have been found: extinct Camelidae, Cervidae, Equidae, Mylodontidae, Xenarthra, but also Myocastoridae, Canidae and Octodontidae. Both geological and paleoenvironmental data indicate that GNLQ1 developed in a floodplain or low-energy environment during the Last Glacial Maximum (LGM). Prior to the post-glacial rising of the sea level, the site would have been located several kilometres inland as the paleoshoreline was farther out on the continental shelf. In accordance with this background, the present study addresses the analysis of the spatial distribution of the bone deposits of GNLQ1 by considering both scenarios, the terrestrial phase related to the formation and modification of the fossil assemblage prior to the transgression, and the marine phase, subsequent to inundation. Results indicate modifications related to low-energy flow environment and carnivore activity dominated during the terrestrial phase and the action of marine organisms during the marine phase. Other taphonomic modifications are not easily attributable to either one or the other environmental context. 相似文献
60.
The Krafla geothermal system is located in Iceland's northeastern neovolcanic zone, within the Krafla central volcanic complex. Geothermal fluids are superheated steam closest to the magma heat source, two‐phase at higher depths, and sub‐boiling at the shallowest depths. Hydrogen isotope ratios of geothermal fluids range from ?87‰, equivalent to local meteoric water, to ?94‰. These fluids are enriched in 18O relative to the global meteoric line by +0.5–3.2‰. Calculated vapor fractions of the fluids are 0.0–0.5 wt% (~0–16% by volume) in the northwestern portion of the geothermal system and increase towards the southeast, up to 5.4 wt% (~57% by volume). Hydrothermal epidote sampled from 900 to 2500 m depth has δD values from ?127 to ?108‰, and δ18O from ?13.0 to ?9.6‰. Fluids in equilibrium with epidote have isotope compositions similar to those calculated for the vapor phase of two‐phase aquifer fluids. We interpret the large range in δDEPIDOTE and δ18OEPIDOTE across the system and within individual wells (up to 7‰ and 3.3‰, respectively) to result from variable mixing of shallow sub‐boiling groundwater with condensates of vapor rising from a deeper two‐phase reservoir. The data suggest that meteoric waters derived from a single source in the northwest are separated into the shallow sub‐boiling reservoir, and deeper two‐phase reservoir. Interaction between these reservoirs occurs by channelized vertical flow of vapor along fractures, and input of magmatic volatiles further alters fluid chemistry in some wells. Isotopic compositions of hydrothermal epidote reflect local equilibrium with fluids formed by mixtures of shallow water, deep vapor condensates, and magmatic volatiles, whose ionic strength is subsequently derived from dissolution of basalt host rock. This study illustrates the benefits of combining phase segregation effects in two‐phase systems during analysis of wellhead fluid data with stable isotope values of hydrous alteration minerals when evaluating the complex hydrogeology of volcano‐hosted geothermal systems. 相似文献