首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   26篇
  免费   0篇
教育   8篇
科学研究   8篇
体育   6篇
文化理论   1篇
信息传播   3篇
  2020年   1篇
  2019年   3篇
  2018年   1篇
  2017年   2篇
  2015年   2篇
  2014年   1篇
  2013年   2篇
  2012年   1篇
  2011年   2篇
  2009年   1篇
  2008年   2篇
  2007年   1篇
  2003年   1篇
  2001年   1篇
  2000年   1篇
  1999年   1篇
  1993年   1篇
  1991年   1篇
  1988年   1篇
排序方式: 共有26条查询结果,搜索用时 15 毫秒
11.
12.
Manoeuvring a motorcycle at high-speed in official competition has been shown to expose riders to substantial and complex physiological and psychological demands, however few studies have analysed the physical load experienced by professional racers. This study aimed to quantify the physical stress experienced by riders and explore relationships between performance related variables (i.e. crashes). Performance and braking data were collected from official race reports from 2013 to 2015 of the top class of the FIM Road Racing Grand Prix World Championship. Top-level riders are exposed to a considerable volume (175 ± 42 brakes and 372 ± 48 leans to corner per race) of high intensity actions (>40% of brakes initiated at speeds higher than 260 km.h?1, and 13.2% over 300 km.h?1), where 1 out of every 4 braking actions generated inertial stresses greater than 10 m.s?2. Furthermore, the mean speed across competitions increased over the years (from 161.7 ± 6 km.h?1 to 164.5 ± 6 km.h?1), however no clear relationships between the amount of crashes and competition-related factors were found. Given the findings it would seem that riders could benefit from strength training specifically designed to prepare the body to counteract the repetitive inertial stresses of racing.  相似文献   
13.
In this paper, we illustrate the development of a realistic simulation of a humanoid robot model in a virtual environment using USARSim (Urban Search and Rescue Simulator). USARSim provides an accurate 3D simulation of a virtual environment with a detailed rendering and a realistic physics. Moreover, USARSim allows users to observe the virtual environment from different views. One of these is the egocentric view, which can simulate the camera mounted on the robot. The small humanoid robot presented in this work is Robovie-M, developed by VStone Ltd. (Japan). This robot is used by our team Artisti in the RobotCup soccer competitions.Reported experiments compare the behaviors of a real robot and of its virtual model, when controlled by the same control software to asses the possibility to faithfully simulate a robot with 22 degrees of freedom in USARSim. Moreover, we discuss the possibility to close the control loop of the robot in simulation, by simulating also the main robot sensor, i.e. the camera.The experiments show that USARSim, despite being a simple simulator based on a low cost computer game, provides an accurate enough simulation of the physics and a realistic rendering of the 3D scene enabling a faithful simulation of a small humanoid robot at low cost. Thus, one can entirely test the robot software modules in the simulation (namely: the motion control modules, the vision system modules and, by closing the robot control loop in simulation, the behavior and behavior-selection modules).  相似文献   
14.
Heart rate and blood lactate concentration of male road-race motorcyclists   总被引:1,自引:1,他引:0  
Although motorcycling performance strongly depends on the characteristics of the motorcycles and capabilities of the riders, little information is available on the physiological profiles of riders. The aim of this study was to evaluate the physical load of official international men's road-race motorcycling competitions. Data were obtained from 34 male riders during the 2005 European Road-Race Motorcycling Championship (categories classified by size of engine: 125 GP, 250 GP, and 600 cc) during free practices, qualifying sessions, and official races. Participants' heart rates were recorded and blood lactate concentrations determined. During races, heart rates were most often above 90% of maximum heart rate (frequency of occurrence: 125 GP = 92.9%, s = 5.3; 250 GP = 93.6%, s = 7.3; 600 cc = 93.2%, s = 10.2). The heart rate distribution during riding showed main effects between phases of competition, engine sizes, and different portions of the race (P < 0.001). No difference was observed between riders on and not on the podium at the end of the race. Peak blood lactate concentrations after the qualifying sessions (5.2 mmol . l(-1), s = 1.2) and official races (6.0 mmol . l(-1), s = 2.1) were higher (P < 0.001) than at baseline. The present results show that road-race motorcycling imposes a high load on the riders, who should possess adequate fitness to maintain high-speed rides and minimize the effects of fatigue during competition.  相似文献   
15.
Within the perimeter of patent collaboration networks, the average distance of collaborations and the number of countries involved per each collaboration have been shown to have increased steadily in time. Less attention, though, has been devoted to assessing whether this growth of cross-country collaborations is stable in time. To address this scientific question we focus on the identification of long-term correlations (i.e. temporal persistence). Our data set consists of time series of yearly average collaboration radii and of cross-border links in the Euro-American subsystem of the global collaboration network for the period 1978–2014. To investigate the fundamental persistence properties of these time series, we use Detrended Fluctuation Analysis, a method that allows us to measure long-term correlations in detrended signals. Also, we devise a general and original procedure to assess the statistical significance of results for short time series. Our results, showing that long-term correlations do exist in the majority of our signals, reinforce the hypothesis of a diminishing role of geographical distance in technological collaborations. Results at national level show that a significant degree of heterogeneity in persistence parameters can be detected within Europe, irrespectively of the efforts towards the set-up of an integrated European Research Area.  相似文献   
16.
Healthcare organisations are facing the constant trade off to contain expenditures without sacrificing the quality of patient's care. This challenge to do ‘more with less’ induced healthcare executives to heavily invest in innovations activities in order to increase the efficiency of their organisations. By taking an individual-level perspective, our study focuses on knowledge-sharing behaviour among healthcare practitioners as a critical element to continuously improve the performance of healthcare organisations. Specifically we explore the effect of intellectual capital on practitioners’ knowledge-sharing behaviour, and propose organisational knowledge-sharing climate as mediator. We conducted a survey on three healthcare organisations. Our results substantiate the positive link between intellectual capital and knowledge-sharing behaviour, and reveal that organisational knowledge-sharing climate fully mediates this relationship. These findings provide hospital managers with key implications for the management of intellectual capital as a lever to improve the sharing and the diffusion of knowledge among practitioners.  相似文献   
17.
This study aimed at determining the amount of Italian television coverage dedicated to men's and women's sport and the number of male and female viewers during the 2004 Summer Olympic Games. AUDITEL-AGB Nielsen Media Research Italia provided the TV airtime data for the sport events broadcast, which were classified into three categories: men-only, women-only, and mixed-gender. The viewer sample was divided by age and gender and included three audience parameters: mean audience, share, and appreciation index. The last item is calculated from the program duration, audience permanence, and the share related to programs broadcast by other Italian channels. In particular, the appreciation index was used to investigate the relationship between (a) the viewer's and sport participants' gender and (b) the effect of Italian participation and expectations for sport achievement. The data showed that Italian male athletes outnumbered their female counterparts. Women's sport was allotted significantly less airtime than men's sport, but this imbalance was not proportional to the gender difference in the overall athletes' participation in the Games. Although the female audience represented 45% of the total, a significantly higher male mean audience and share were found. On the other hand, the appreciation of men's and women's sport events was balanced after equating for differences in media coverage. Moreover sport achievement might have a positive effect on the trend toward equality of gender coverage, indicating that a global multisport event such as the Olympic Games is central to communicating a national image and identity independently of the athletes' gender.  相似文献   
18.
Bezuidenhout  Louise  Ratti  Emanuele  Warne  Nathaniel  Beeler  Dori 《Minerva》2019,57(1):67-84
Minerva - Scientific epistemology is a topic that has sparked centuries of philosophical discourse. In particular, understanding the role that scientists play in the creation and perpetuation of...  相似文献   
19.
A porous silicon (PSi) based microarray has been integrated with a microfluidic system, as a proof of concept device for the optical monitoring of selective label-free DNA-DNA interaction. A 4 × 4 square matrix of PSi one dimensional photonic crystals, each one of 200 μm diameter and spaced by 600 μm, has been sealed by a polydimethylsiloxane (PDMS) channels circuit. The PSi optical microarray elements have been functionalized by DNA single strands after sealing: the microfluidic circuit allows to reduce significantly the biologicals and chemicals consumption, and also the incubation time with respect to a not integrated device. Theoretical calculations, based on finite element method, taking into account molecular interactions, are in good agreement with the experimental results, and the developed numerical model can be used for device optimization. The functionalization process and the interaction between DNA probe and target has been monitored by spectroscopic reflectometry for each PSi element in the microchannels.  相似文献   
20.
The strategies used to solve mental and written multidigit arithmetical addition, subtraction, multiplication and division were observed in 200 third, fourth and fifth grade children. A strategy was classified as effective if it resulted in the correct solution at least 75% of the time. For mental addition and subtraction, primitive strategies such as counting on fingers and counting on (mental counting from a specific point), and the more sophisticated strategy 1010 (solution of the calculation problem using tens and units separately) were more effective than the strategies learned at school. In written addition, subtraction and multiplication there was a shift from the CAR+to the CAR- strategy (tabulating with, or without, a carried amount) from the third to the later grades. Results show that typical strategies taught at school progressively substitute every other strategy both in mental and written calculation, but without reaching the criterion of effectiveness. The implications for maths curricula are discussed.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号