全文获取类型
收费全文 | 443篇 |
免费 | 8篇 |
专业分类
教育 | 287篇 |
科学研究 | 54篇 |
各国文化 | 4篇 |
体育 | 78篇 |
文化理论 | 10篇 |
信息传播 | 18篇 |
出版年
2024年 | 1篇 |
2023年 | 1篇 |
2022年 | 3篇 |
2021年 | 17篇 |
2020年 | 14篇 |
2019年 | 31篇 |
2018年 | 32篇 |
2017年 | 26篇 |
2016年 | 22篇 |
2015年 | 18篇 |
2014年 | 22篇 |
2013年 | 78篇 |
2012年 | 14篇 |
2011年 | 20篇 |
2010年 | 13篇 |
2009年 | 10篇 |
2008年 | 10篇 |
2007年 | 14篇 |
2006年 | 6篇 |
2005年 | 14篇 |
2004年 | 8篇 |
2003年 | 5篇 |
2002年 | 8篇 |
2001年 | 2篇 |
2000年 | 3篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 6篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 4篇 |
1993年 | 1篇 |
1991年 | 1篇 |
1990年 | 1篇 |
1989年 | 5篇 |
1988年 | 3篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1974年 | 1篇 |
1970年 | 3篇 |
1969年 | 1篇 |
1887年 | 2篇 |
排序方式: 共有451条查询结果,搜索用时 265 毫秒
441.
In this work a procedure for obtaining polytopic λ-contractive sets for Takagi–Sugeno fuzzy systems is presented, adapting well-known algorithms from literature on discrete-time linear difference inclusions (LDI) to multi-dimensional summations. As a complexity parameter increases, these sets tend to the maximal invariant set of the system when no information on the shape of the membership functions is available. λ-contractive sets are naturally associated to level sets of polyhedral Lyapunov functions proving a decay-rate of λ. The paper proves that the proposed algorithm obtains better results than a class of Lyapunov methods for the same complexity degree: if such a Lyapunov function exists, the proposed algorithm converges in a finite number of steps and proves a larger λ-contractive set. 相似文献
442.
Bruno Pereira de Moura João Carlos Bouzas Marins Sylvia Do Carmo Castro Franceschini Janice Sepúlveda Reis Paulo Roberto Dos Santos Amorim 《Journal of sports sciences》2015,33(6):545-551
Although exercise promotes beneficial effects in diabetic patients, some studies have questioned the degree of their importance in terms of the increase in total energy expenditure. In these studies, the decrease of physical activity levels (PAL) was referred as “compensatory effect of exercise”. However, our aim was to investigate whether aerobic exercise has compensatory effects on PAL in type 2 diabetes patients. Eight volunteers (51.1 ± 8.2 years) were enrolled in a supervised exercise programme for 8 weeks (3 d · wk?1, 50–60% of VO2 peak for 30–60 min). PAL was measured using tri-axial accelerometers in the 1st, 8th and 12th weeks. Biochemical tests, cardiorespiratory fitness, anthropometric assessment and body composition were measured in the 2nd and 11th weeks. Statistical analysis was performed using non-parametric tests (Friedman and Wilcoxon, P < 0.05). We found no significant differences in PAL between intervention periods, and participants spent the majority of their awake time in sedentary activities. However, the exercise programme generated a significant 14.8% increase in VO2 peak and a 15% reduction in fructosamine. The exercise programme had no compensatory effects on PAL in type 2 diabetes patients, but improved their cardiorespiratory fitness and glycaemic control. 相似文献
443.
Carlos Balsalobre-Fernández Mark Glaister Richard Anthony Lockey 《Journal of sports sciences》2015,33(15):1574-1579
The purpose of this investigation was to analyse the concurrent validity and reliability of an iPhone app (called: My Jump) for measuring vertical jump performance. Twenty recreationally active healthy men (age: 22.1 ± 3.6 years) completed five maximal countermovement jumps, which were evaluated using a force platform (time in the air method) and a specially designed iPhone app. My jump was developed to calculate the jump height from flight time using the high-speed video recording facility on the iPhone 5 s. Jump heights of the 100 jumps measured, for both devices, were compared using the intraclass correlation coefficient, Pearson product moment correlation coefficient (r), Cronbach’s alpha (α), coefficient of variation and Bland–Altman plots. There was almost perfect agreement between the force platform and My Jump for the countermovement jump height (intraclass correlation coefficient = 0.997, P < 0.001; Bland–Altman bias = 1.1 ± 0.5 cm, P < 0.001). In comparison with the force platform, My Jump showed good validity for the CMJ height (r = 0.995, P < 0.001). The results of the present study showed that CMJ height can be easily, accurately and reliably evaluated using a specially developed iPhone 5 s app. 相似文献
444.
Maria Salinas Maite López-Garrigós Emilio Flores Ana Santo-Quiles Mercedes Gutierrez Javier Lugo Rosa Lillo Carlos Leiva-Salinas 《Biochemia medica : ?asopis Hrvatskoga dru?tva medicinskih biokemi?ara / HDMB》2015,25(1):49-56
Introduction
Preanalytical control and monitoring continue to be an important issue for clinical laboratory professionals. The aim of the study was to evaluate a monitoring system of preanalytical errors regarding not suitable samples for analysis, based on different indicators; to compare such indicators in different phlebotomy centres; and finally to evaluate a single synthetic preanalytical indicator that may be included in the balanced scorecard management system (BSC).Materials and methods
We collected individual and global preanalytical errors in haematology, coagulation, chemistry, and urine samples analysis. We also analyzed a synthetic indicator that represents the sum of all types of preanalytical errors, expressed in a sigma level. We studied the evolution of those indicators over time and compared indicator results by way of the comparison of proportions and Chi-square.Results
There was a decrease in the number of errors along the years (P < 0.001). This pattern was confirmed in primary care patients, inpatients and outpatients. In blood samples, fewer errors occurred in outpatients, followed by inpatients.Conclusion
We present a practical and effective methodology to monitor unsuitable sample preanalytical errors. The synthetic indicator results summarize overall preanalytical sample errors, and can be used as part of BSC management system.Key words: Preanalytical phase, errors in laboratory medicine, balanced scorecard, patient safety 相似文献445.
Entrepreneurs use resources and capacities to form core competencies. These are competitive advantages if they produce better company performance. Intellectual capital (IC) is a key resource for competitive advantage. This paper analyses the process through which entrepreneurs use this resource to obtain competitive advantages in regional SMEs. We show how entrepreneurs constitute three core competencies with IC and territory: internal knowledge management, relationship management and innovativeness. By partial least squares techniques we demonstrate that: (i) the two first factors influence innovativeness; (ii) this dynamic affects company performance. The study contributes to the analysis of the process of building core competencies by the entrepreneur from IC, in order to get better company performance. 相似文献
446.
We use the results of a public opinion survey we carried out in 2012 on a sample of the Spanish adult population to offer a plausible explanation of one of the main conundrums of primary and secondary school teachers' prestige, not only in Spain, i.e. that, contrary to public discourse and to teachers' perceptions, this prestige has not fallen in the last decades, but has remained middle to high. The estimates of teachers' prestige made by the public are the same (roughly, around 70 in a 0 to 100 scale) as those that were measured in the early 1990s. However, a clear majority of the public believes that teachers' prestige has fallen in the last decades, reiterating a cliché that is widespread in the Spanish public sphere, especially among teachers. We hypothesise that the perception of the falling prestige is much more a matter of a public space dominated by the media than of a public space that is more confined to everyday experiences and to the citizens' basic values. We support our hypothesis with pieces of empirical evidence related, on the one hand, to the association of that perception with media consumption variables in our survey, and, on the other, to media (negative) treatment of teachers' prestige. In our argument, we are also helped by a literature that is not usually dealt with in studies of teachers' prestige: that of media influence in the formation of public opinions regarding other people's opinions. 相似文献
447.
448.
Alejandro Bastida Castillo Carlos D. Gómez Carmona Ernesto De la cruz sánchez José Pino Ortega 《European Journal of Sport Science》2018,18(4):450-457
There is interest in the accuracy and inter-unit reliability of position-tracking systems to monitor players. Research into this technology, although relatively recent, has grown exponentially in the last years, and it is difficult to find professional team sport that does not use Global Positioning System (GPS) technology at least. The aim of this study is to know the accuracy of both GPS-based and Ultra Wide Band (UWB)-based systems on a soccer field and their inter- and intra-unit reliability. A secondary aim is to compare them for practical applications in sport science. Following institutional ethical approval and familiarization, 10 healthy and well-trained former soccer players (20?±?1.6 years, 1.76?±?0.08?cm, and 69.5?±?9.8?kg) performed three course tests: (i) linear course, (ii) circular course, and (iii) a zig–zag course, all using UWB and GPS technologies. The average speed and distance covered were compared with timing gates and the real distance as references. The UWB technology showed better accuracy (bias: 0.57–5.85%), test–retest reliability (%TEM: 1.19), and inter-unit reliability (bias: 0.18) in determining distance covered than the GPS technology (bias: 0.69–6.05%; %TEM: 1.47; bias: 0.25) overall. Also, UWB showed better results (bias: 0.09; ICC: 0.979; bias: 0.01) for mean velocity measurement than GPS (bias: 0.18; ICC: 0.951; bias: 0.03). 相似文献
449.
450.
Carlos Cobos Orlando Rodriguez Jarvein Rivera John Betancourt Martha Mendoza Elizabeth León Enrique Herrera-Viedma 《Information processing & management》2013
To carry out effective teaching/learning processes, lecturers in a variety of educational institutions frequently need support. They therefore resort to advice from more experienced lecturers, to formal training processes such as specializations, master or doctoral degrees, or to self-training. High costs in time and money are invariably involved in the processes of formal training, while self-training and advice each bring their own specific risks (e.g. of following new trends that are not fully evaluated or the risk of applying techniques that are inappropriate in specific contexts).This paper presents a system that allows lecturers to define their best teaching strategies for use in the context of a specific class. The context is defined by: the specific characteristics of the subject being treated, the specific objectives that are expected to be achieved in the classroom session, the profile of the students on the course, the dominant characteristics of the teacher, and the classroom environment for each session, among others. The system presented is the Recommendation System of Pedagogical Patterns (RSPP). To construct the RSPP, an ontology representing the pedagogical patterns and their interaction with the fundamentals of the educational process was defined. A web information system was also defined to record information on courses, students, lecturers, etc.; an option based on a unified hybrid model (for content and collaborative filtering) of recommendations for pedagogical patterns was further added to the system. RSPP features a minable view, a tabular structure that summarizes and organizes the information registered in the rest of the system as well as facilitating the task of recommendation. The data recorded in the minable view is taken to a latent space, where noise is reduced and the essence of the information contained in the structure is distilled. This process makes use of Singular Value Decomposition (SVD), commonly used by information retrieval and recommendation systems. Satisfactory results both in the accuracy of the recommendations and in the use of the general application open the door for further research and expand the role of recommender systems in educational teacher support processes. 相似文献