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51.
According to the knowledge-spillovers theory of entrepreneurship (KSTE), local knowledge spillovers affect entrepreneurial dynamics, because of knowledge asymmetries and uncertainty. Most of the empirical literature has tested this hypothesis using a measure of local knowledge stock. This paper is aimed at extending the framework by showing that the domains over which local knowledge spans are also important. The paper investigates the impact of the configuration of local knowledge bases on new firm formation dynamics by combining the KSTE framework with the recombinant knowledge approach. Local knowledge bases emerge from the combination of different knowledge inputs. These inputs may be closely or loosely related to one another. Technological differentiation and the relatedness degree of local competences can be interpreted as characteristics of the local knowledge base interacting with the knowledge filter and the entrepreneurial absorptive capacity. The paper proposes a taxonomy of regional modes of knowledge production and investigates new firm formation in 92 Italian NUTS 3 regions observed over the 1995–2009 time span. The results confirm that the availability of local knowledge pools is important, and show that the ‘rich integration’ mode is the configuration that favours the entrepreneurial process. Finally, the policy implications and avenues for further research are presented and discussed.  相似文献   
52.
53.
Introduction     
Former Professor at the University of La Plata and the Latin American Faculty of Social Sciences, Argentina. His research deals with the sociology of education and the development process. Author of Educación y sociedad en Argentina (1971, reprinted 1979, 1981), Conceptos de sociología de la educación (1980, published in Portuguese in 1982) and El desafío educativo: calidad y democracia (1986).  相似文献   
54.
The ‘Bologna process’ is promoting fundamental changes throughout European higher education. Education ministers appear determined to reach, by 2010, a significant convergence of the national educational systems. This implies the necessity of adapting curricula in terms of structures, contents, learning attributes, learning tools and assessment methods. The EC ‘Tuning’ project was set up in order to investigate the feasibility of this process on the basis of ‘available experience and recent developments in several of the Member states… particularly from previous and on-going European co-operation in the context of the Socrates programme’. The Tuning project, initially aimed at five areas only (mathematics, geology, business, history, educational sciences), was later extended to other areas, including engineering: synergy groups were formed for this purpose. This paper summarizes the final report of the Engineering Synergy Group, which examined the ‘tuning’ of engineering education (EE) into European higher education, taking advantage of the work of previous and current thematic networks, such as H3E, EUCEET and E4. A set of recommendations is presented in the final section of the paper.  相似文献   
55.
Editorial     
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56.
The expansion of the Italian university system in the 1960s and 1970s is described with particular reference to the laws of 1961 and 1969 which liberalized access. The effects of these reforms are discussed and it is argued that despite the expansion the system remains an élite system. Admission to prestigious faculties and failure rates are correlated with social class to show that selection by failure within the university may to some extent have replaced selection at entry as a way of maintaining an élite system. Despite the increase in wastage there is a growing mismatch between the demand for and supply of graduate labour and this has given rise to social tensions.  相似文献   
57.
While research outside economics has found that drinking has a negative effect on cognitive skills, some economists have failed to find any negative relationship between drinking and academic performance. This paper argues that the reason for this discrepancy is due to the way education is measured in the economic literature. Herein, binge drinking in the senior year of high school is found to reduce the probability of receiving a high school diploma and to increase the probability of graduating with a General Education Development (GED). Moreover, this study finds that alcohol policies do not affect the dropout rate measured at the age of 25, but they do affect the probability that a student will graduate on time. In conclusion, bingeing is found to be responsible for inducing individuals to temporarily drop out of school. Eventually, these individuals return to school to complete their education, most likely by obtaining a GED diploma.  相似文献   
58.
The application of microfluidic technologies to stem cell research is of great interest to biologists and bioengineers. This is chiefly due to the intricate ability to control the cellular environment, the reduction of reagent volume, experimentation time and cost, and the high-throughput screening capabilities of microscale devices. Despite this importance, a simple-to-use microfluidic platform for studying the effects of growth factors on stem cell differentiation has not yet emerged. With this consideration, we have designed and characterized a microfluidic device that is easy to fabricate and operate, yet contains several functional elements. Our device is a simple polyester-based microfluidic chip capable of simultaneously screening multiple independent stem cell culture conditions. Generated by laser ablation and stacking of multiple layers of polyester film, this device integrates a 10 × 10 microwell array for cell culture with a continuous perfusion system and a non-linear concentration gradient generator. We performed numerical calculations to predict the gradient formation and calculate the shear stress acting on the cells inside the device. The device operation was validated by culturing murine embryonic stem cells inside the microwells for 5 days. Furthermore, we showed the ability to maintain the pluripotency of stem cell aggregates in response to concentrations of leukemia inhibitory factor ranging from 0 to ∼1000 U/ml. Given its simplicity, fast manufacturing method, scalability, and the cell-compatible nature of the device, it may be a useful platform for long-term stem cell culture and studies.  相似文献   
59.
This study explores the channels through which technological investments affect productivity performance of industrialized economies. Using a Stochastic Frontier Model (SFM) we estimate the productivity effects of R&D and ICT for a large sample of OECD industries between 1973 and 2007, identifying four channels of transmission: input accumulation, technological change, technical efficiency and spillovers. Our results show that ICT has been particularly effective in reducing production inefficiency and in generating inter-industry spillovers, while R&D has raised the rate of technical change and favoured knowledge spillovers within sectors. We also quantify the contribution of technological investments to output and total factor productivity growth documenting that R&D and ICT accounted for almost 95% of productivity growth in the OECD area.  相似文献   
60.
Query reformulation mining: models,patterns, and applications   总被引:1,自引:0,他引:1  
Understanding query reformulation patterns is a key task towards next generation web search engines. If we can do that, then we can build systems able to understand and possibly predict user intent, providing the needed assistance at the right time, and thus helping users locate information more effectively and improving their web-search experience. As a step in this direction, we build a very accurate model for classifying user query reformulations into broad classes (generalization, specialization, error correction or parallel move), achieving 92% accuracy. We then apply the model to automatically label two very large query logs sampled from different geographic areas, and containing a total of approximately 17 million query reformulations. We study the resulting reformulation patterns, matching some results from previous studies performed on smaller manually annotated datasets, and discovering new interesting reformulation patterns, including connections between reformulation types and topical categories. We annotate two large query-flow graphs with reformulation type information, and run several graph-characterization experiments on these graphs, extracting new insights about the relationships between the different query reformulation types. Finally we study query recommendations based on short random walks on the query-flow graphs. Our experiments show that these methods can match in precision, and often improve, recommendations based on query-click graphs, without the need of users’ clicks. Our experiments also show that it is important to consider transition-type labels on edges for having recommendations of good quality.  相似文献   
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