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   1609篇
  免费   35篇
  国内免费   2篇
教育   1114篇
科学研究   97篇
各国文化   36篇
体育   189篇
综合类   2篇
文化理论   22篇
信息传播   186篇
  2024年   2篇
  2023年   9篇
  2022年   19篇
  2021年   23篇
  2020年   49篇
  2019年   82篇
  2018年   92篇
  2017年   92篇
  2016年   78篇
  2015年   57篇
  2014年   67篇
  2013年   379篇
  2012年   57篇
  2011年   54篇
  2010年   49篇
  2009年   43篇
  2008年   46篇
  2007年   53篇
  2006年   41篇
  2005年   33篇
  2004年   36篇
  2003年   20篇
  2002年   28篇
  2001年   13篇
  2000年   16篇
  1999年   13篇
  1998年   11篇
  1997年   17篇
  1996年   11篇
  1995年   15篇
  1994年   8篇
  1993年   4篇
  1992年   16篇
  1991年   11篇
  1990年   8篇
  1989年   9篇
  1988年   9篇
  1987年   8篇
  1986年   4篇
  1985年   7篇
  1984年   14篇
  1983年   8篇
  1982年   7篇
  1981年   2篇
  1980年   6篇
  1979年   3篇
  1978年   6篇
  1977年   2篇
  1967年   3篇
  1955年   1篇
排序方式: 共有1646条查询结果,搜索用时 31 毫秒
121.
122.
This study examined the utility of Ajzen's (1985) theory of planned behaviour and Maddux's (1993) revised theory of planned behaviour to predict endurance training intentions and adherence of elite junior netball athletes. One hundred and fifteen athletes from the England Netball World Class Start Programme were assessed on constructs central to the predictions of the two theories. Adherence to a recommended endurance training programme was recorded in self-report diaries across a 9-week period. Validity for the diaries was supported by significant correlations (P < 0.001) with recalls across 7 days and 9 weeks. Adherence was moderate and variable between athletes (mean = 66.05, s = 25.75%). Two separate path analyses were conducted to examine the predictions of the theories. Goodness-of-fit indices suggested acceptable fit of the data to the models. Analyses showed that attitude towards the new behaviour, subjective norms and perceived behavioural control predicted training intentions. The relationship between intention and adherence was weak. The present results suggest that the constructs of the theory of planned behaviour offer some insight into the explanation of intentions to follow an endurance training programme. Constructs unique to the revised theory of planned behaviour did not significantly predict training intentions or behaviour. Implications for practitioners working with team sport performers are provided.  相似文献   
123.
Effects of competition, exercise, and mental stress on secretory immunity   总被引:2,自引:0,他引:2  
It has been suggested that the psychological stress associated with competitive sports events may help to explain the increased susceptibility to respiratory infections due to reductions in secretory immunity. In the current study, we investigated the influence of competitive exercise and psychological stress on secretory immunoglobulin A (s-IgA). Salivary s-IgA and heart rate were measured in 62 healthy young recreationally active men at rest and, in a between-subjects design, following one of four 8-min tasks: mental arithmetic, cycling at workloads of 60 to 180 W (mean = 146 W), mental arithmetic while cycling, or competitive cycling. Mental arithmetic was associated with significant increases in s-IgA concentration (mean = 49 microg.min(-1)) and s-IgA secretion rate (mean = 25 microg.ml(-1)) compared with rest, while mental arithmetic combined with exercise was associated with a significant increase in s-IgA concentration only (mean = 124 microg.min(-1)). In contrast, competitive exercise and exercise alone did not influence s-IgA concentration or secretion rate. Heart rate increased modestly to mental arithmetic (mean = 7 beats.min(-1)) and substantially, and similarly, to the three exercise tasks (mean = 56(62 beats.min(-1)). The hypothesis that the psychological stress of competitive exercise contributes to increased susceptibility to infection via reductions in s-IgA requires further investigation.  相似文献   
124.
125.
This paper proposes a new sliding mode observer for fault reconstruction, applicable for a class of linear parameter varying (LPV) systems. Observer schemes for actuator and sensor fault reconstruction are presented. For the actuator fault reconstruction scheme, a virtual system comprising the system matrix and a fixed input distribution matrix is used for the design of the observer. The fixed input distribution matrix is instrumental in simplifying the synthesis procedure to create the observer gains to ensure a stable closed-loop reduced order sliding motion. The ‘output error injection signals’ from the observer are used as the basis for reconstructing the fault signals. For the sensor fault observer design, augmenting the LPV system with a filtered version of the faulty measurements allows the sensor fault reconstruction problem to be posed as an actuator fault reconstruction scenario. Simulation tests based on a high-fidelity nonlinear model of a transport aircraft have been used to demonstrate the proposed actuator and sensor FDI schemes. The simulation results show their efficacy.  相似文献   
126.
The purposes of this study were (1) to determine the functional swing plane (FSP) of the clubhead and the motion planes (MPs) of the shoulder/arm points and (2) to assess planarity of the golf swing based on the FSP and the MPs. The swing motions of 14 male skilled golfers (mean handicap = -0.5 +/- 2.0) using three different clubs (driver, 5-iron, and pitching wedge) were captured by an optical motion capture system (250Hz). The FSP and MPs along with their slope/relative inclination and direction/direction of inclination were obtained using a new trajectory-plane fitting method. The slope and direction of the FSP revealed a significant club effect (p < 0.001). The relative inclination and direction of inclination of the MP showed significant point (p < 0.001) and club (p < 0.001) effects and interaction (p < 0.001). Maximum deviations of the points from the FSP revealed a significant point effect (p < 0.001) and point-club interaction (p < 0.001). It was concluded that skilled golfers exhibited well-defined and consistent FSP and MPs, and the shoulder/arm points moved on vastly different MPs and exhibited large deviations from the FSP. Skilled golfers in general exhibited semi-planar downswings with two distinct phases: a transition phase and a planar execution phase.  相似文献   
127.
128.
College-level biology courses contain many complex processes that are often taught and learned as detailed narratives. These processes can be better understood by perceiving them as dynamic systems that are governed by common fundamental principles. Conservation of matter is such a principle, and thus tracing matter is an essential step in learning to reason about biological processes. We present here multiple-choice questions that measure students' ability and inclination to trace matter through photosynthesis and cellular respiration. Data associated with each question come from students in a large undergraduate biology course that was undergoing a shift in instructional strategy toward making fundamental principles (such as tracing matter) a central theme. We also present findings from interviews with students in the course. Our data indicate that 1) many students are not using tracing matter as a tool to reason about biological processes, 2) students have particular difficulties tracing matter between systems and have a persistent tendency to interconvert matter and energy, and 3) instructional changes seem to be effective in promoting application of the tracing matter principle. Using these items as diagnostic tools allows instructors to be proactive in addressing students' misconceptions and ineffective reasoning.  相似文献   
129.
130.
Outcome-based education (OBE) is a current initiative in Hong Kong universities, with widespread backing by governments and standards bodies. However, study of students’ perceptions of OBE and validation of understanding these perceptions are lacking. This paper reports on the validation of an OBE-specific instrument and resulting preliminary findings. Instrument responses (= 89) were analysed using Rasch and exploratory/confirmatory factor analyses. Both approaches identified two dimensions (i.e. evaluation and comparison). Challenges and modifications to the instrument items and their relationships to constructs are discussed. Preliminary findings suggest students did not perceive significant differences between OBE and traditionally organised courses. Lack of explicit discussion of OBE with the students may have denied students the ability to make fully informed evaluations of OBE innovations. Implications for instrument validation and evaluation of initiatives in an OBE context are discussed as is the broader issue of transparency in teacher education curriculum design and implementation.  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