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101.
Yang Gao Feng Zhou Philippe Ciais Chiyuan Miao Tao Yang Yanlong Jia Xudong Zhou Butterbach-Bahl Klaus Tiantian Yang Guirui Yu 《国家科学评论(英文版)》2020,7(2):430
In the past three decades, China has built more than 87 000 dams with a storage capacity of ≈6560 km3 and the total surface area of inland water has increased by 6672 km2. Leaching of N from fertilized soils to rivers is the main source of N pollution in China, but the exposure of a growing inland water area to direct atmospheric N deposition and N leaching caused by N deposition on the terrestrial ecosystem, together with increased N deposition and decreased N flow, also tends to raise N concentrations in most inland waters. The contribution of this previously ignored source of N deposition to freshwaters is estimated in this study, as well as mitigation strategies. The results show that the annual amounts of N depositions ranged from 4.9 to 16.6 kg · ha−1 · yr−1 in the 1990s to exceeding 20 kg · ha−1 · yr−1 in the 2010s over most of regions in China, so the total mass of ΔN (the net contribution of N deposition to the increase in N concentration) for lakes, rivers and reservoirs change from 122.26 Gg N · yr−1 in the 1990s to 237.75 Gg N · yr−1 in the 2010s. It is suggested that reducing the N deposition from various sources, shortening the water-retention time in dams and decreasing the degree of regulation for rivers are three main measures for preventing a continuous increase in the N-deposition pollution to inland water in China. 相似文献
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Agricultural science and technology (S&T) is under great scrutiny. Reorientation towards more holistic approaches, including agroecology, has recently been backed by a global international assessment of agriculture S&T for development (IAASTD). Understanding the past and current trends of agricultural S&T is crucial if such recommendations are to be implemented. This paper shows how the concepts of technological paradigms and trajectories can help analyse the agricultural S&T landscape and dynamics. Genetic engineering and agroecology can be usefully analysed as two different technological paradigms, even though they have not been equally successful in influencing agricultural research. We used a Systems of Innovation (SI) approach to identify the determinants of innovation (the factors that influence research choices) within agricultural research systems. The influence of each determinant is systematically described (e.g. funding priorities, scientists’ cognitive and cultural routines etc.). As a result of their interactions, these determinants construct a technological regime and a lock-in situation that hinders the development of agroecological engineering. Issues linked to breaking out of this lock-in situation are finally discussed. 相似文献
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Philippe C. BAVEYE 《Learned Publishing》2012,25(3):232-234
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In this paper, we examine the factors that influence the reputation or prestige of universities. We first develop a model of university behaviour which indicates how the decisions made by university officials would be chosen in order to maximize their respective reputations. In doing so, we assume that reputation is enhanced by the quality of students produced, the caliber of research and the service provided to the community in terms of the provision of publicly funded education services. We argue that the relative weights placed on these intermediate outputs may vary by university type as well as the means of producing them. Using the results of the reputational survey – a ranking of the institution in terms of reputation – conducted as part of the Canadian magazine Maclean’s overall ranking exercise, we then estimate an Error Correction—Ordered Probit Model of the rankings of Canadian universities to determine the factors that influence the change in reputation or “prestige” of the university as viewed by the external community. We find evidence that the change in reputation of a university is based on what might be considered the appropriate “signals” that one might use in estimating the respective quality of the institution given the respective differences in mission. 相似文献
109.
Vesna Matović Suzana Erić Aleksandar Kremenović Philippe Colomban Danica Srećković-Batoćanin Nenad Matović 《Journal of Cultural Heritage》2012,13(2):175-186
Black crusts formed on limestone built into the King's Gate represent the most important process in stone deterioration that is occurring in this part of the monumental complex of the Belgrade Fortress (Serbia). Of special importance is the association of salts (namely gypsum and syngenite). Syngenite is a common secondary deposit on granite monuments and on medieval stained glass (i.e., on K-containing materials). However, its appearance over calcareous substrates is not apparent, particularly in cases where cement mortar was not used for bounding. The origins of the potassium and sulphate ions required for syngenite formation are related to meteoritic water, which penetrates the soil above the arch of King's Gate. Water dissolves some soil components and becomes enriched with various ions before coming into contact with the limestone blocks. Enriched water contains two times more K+ and SO42? ions than pristine meteoritic water does. The source of the required ions is potassium-sulphate that is present in agricultural fertilisers that are used above the monument. The proposed mechanism for syngenite formation was additionally supported with laboratory experiment. The results of X-ray diffractometry and SEM-EDS analyses of limestone treated with potassium-sulphate solution and sulphuric acid suggest the possibility that the syngenite was formed over calcite:CaCO3 + K2SO4 + H2SO4 → K2Ca(SO4)2 H2O + CO2↑However, the complex mechanisms of gypsum and syngenite formation under natural conditions (variable concentration of potassium and sulphate ions, intermediates phases, temperature changes, humidity, the amount of disposable water etc.) do not exclude the possibility of syngenite formation over gypsum. 相似文献
110.
Investigating the theoretical structure of the DAS‐II core battery at school age using Bayesian structural equation modeling 下载免费PDF全文
Stefan C. Dombrowski Philippe Golay Ryan J. McGill Gary L. Canivez 《Psychology in the schools》2018,55(2):190-207
Bayesian structural equation modeling (BSEM) was used to investigate the latent structure of the Differential Ability Scales—Second Edition core battery using the standardization sample normative data for ages 7–17. Results revealed plausibility of a three‐factor model, consistent with publisher theory, expressed as either a higher‐order (HO) or a bifactor (BF) model. The results also revealed an alternative structure with the best model fit, a two‐factor BF model with Matrices (MA) and Sequential and Quantitative Reasoning (SQ) loading on g only with no respective group factor loading. This was only the second study to use BSEM to investigate the structure of a commercial ability test and the first to use a large normative sample and the specification of both approximate zero cross‐loadings and correlated residual terms. It is believed that the results produced from the current study will advance the field's understanding of not only the factor structure of the DAS‐II core battery but also the potential utility of BSEM in psychometric investigations of intelligence test structures. 相似文献