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   5633篇
  免费   84篇
  国内免费   3篇
教育   4165篇
科学研究   306篇
各国文化   83篇
体育   717篇
综合类   1篇
文化理论   120篇
信息传播   328篇
  2023年   50篇
  2022年   79篇
  2021年   127篇
  2020年   219篇
  2019年   332篇
  2018年   424篇
  2017年   421篇
  2016年   327篇
  2015年   228篇
  2014年   204篇
  2013年   1276篇
  2012年   214篇
  2011年   144篇
  2010年   145篇
  2009年   131篇
  2008年   117篇
  2007年   103篇
  2006年   108篇
  2005年   78篇
  2004年   66篇
  2003年   81篇
  2002年   47篇
  2001年   50篇
  2000年   47篇
  1999年   47篇
  1998年   46篇
  1997年   26篇
  1996年   48篇
  1995年   37篇
  1994年   38篇
  1993年   27篇
  1992年   30篇
  1991年   27篇
  1990年   36篇
  1989年   30篇
  1988年   27篇
  1987年   28篇
  1986年   18篇
  1985年   16篇
  1984年   16篇
  1983年   16篇
  1982年   16篇
  1981年   12篇
  1980年   11篇
  1979年   15篇
  1978年   14篇
  1977年   14篇
  1976年   12篇
  1975年   10篇
  1974年   9篇
排序方式: 共有5720条查询结果,搜索用时 15 毫秒
41.
42.
43.
This study explores working students' college experiences using the grounded theory approach. Focus groups were conducted to allow working students to elaborate on their college experiences, clarifying issues not easily addressed through surveys. Two theoretical propositions are offered to describe how working students are constantly searching for meaningful work as well as meaning in their work. It is important for institutions to consider work as an educationally purposeful activity outside classroom and to create job opportunities that benefit students academically, socially and financially.  相似文献   
44.
A growing body of literature is devoted to testing the reality of the “long-tail” phenomenon. This literature is mostly, if not exclusively, focused on the impact of Internet on the distribution of sales by product. However, the long tail also raises the issue of a possible change in the usual market structure of cultural industries: an oligopoly with a competitive fringe. To our knowledge, no paper addresses the following question: If the long-tail effect does exist, is it of more benefit to small or dominant publishers? The aim of this paper was to address this issue in the context of the French publishing industry. Our main findings are as follows: (1) the market concentration of the French book industry is lower online than offline and (2) the difference in concentration between the two channels of distribution tended to widen over the period 2004–2010. Strategies adopted by leading publishers on the Web do not allow them to maintain the market share obtained with bricks-and-mortar retailers. Furthermore, we show that the market share lost by dominant firms is captured by small publishers online and by medium-sized publishers in conventional stores.  相似文献   
45.
The aim of this study was to examine spatiotemporal characteristics and joint angles during forward and backward walking in water at low and high stride frequency. Eight healthy adults (22.1 ± 1.1 years) walked forward and backward underwater at low (50 pulses) and high frequency (80 pulses) at the xiphoid process level with arms crossed at the chest. The main differences observed were that the participants presented a greater speed (0.58 vs. 0.85 m/s) and more asymmetry of the step length (1.24 vs. 1.48) at high frequency whilst the stride and step length (0.84 vs. 0.7 m and 0.43 vs. 0.35 m, respectively) were lower compared to low frequency (P < 0.05). Support phase duration was higher at forward walking than backward walking (61.2 vs. 59.0%). At initial contact, we showed that during forward walking, the ankle and hip presented more flexion than during backward walking (ankle: 84.0 vs. 91.8º and hip: 22.8 vs. 8.0º; P < 0.001). At final stance, the knee and hip were more flexed at low frequency than at high frequency (knee: 150.0 vs. 157.0º and hip: ?12.2 vs. –14.5º; P < 0.001). The knee angle showed more flexion at forward walking (134.0º) than backward walking (173.1º) (P < 0.001). In conclusion, these results show how forward and backward walking in water at different frequencies differ and contribute to a better understanding of this activity in training and rehabilitation.  相似文献   
46.
47.
This study aimed to verify the prevalence and characteristics of sports injuries (SI) and determine the association between the physical activity level (PA) and SI with perception of health-related quality of life (HRQoL) in Brazilian basketball master athletes. A cross-sectional study was conducted with 410 male master athletes, between 35 and 85 years of age (mean 52.26, SD ±11.83). The HRQoL was assessed using the Medical Outcomes Study – Short Form-36. The PA was evaluated using the International Physical Activity Questionnaire. Information regarding SI was collected using the Reported Morbidity Survey. Poisson regression, as estimated by the prevalence ratio (PR), was used as a measure of the association of PA and SI with HRQoL. The majority of athletes showed a high SI prevalence (58.3%) and reported one injury (67.8%) that occurred during training (61.1%) and primarily affected a lower limb (74.6%). The adjusted regression models showed a positive association of PA with the Functional Capacity (PR = 1.46, 95% confidence interval [CI] = 1.12–1.90) and Physical Component (PR = 1.32, 95% CI = 1.03–1.70) of HRQoL. Furthermore, the SI were negatively associated with HRQoL in Functional Capacity (PR = 1.85, 95% CI = 1.51–2.27), Physical Aspects (PR = 3.99, 95% CI = 3.08–5.18), Pain (PR = 1.65, 95% CI = 1.26–2.16), Social Functioning (PR = 1.79, 95% CI = 1.41–2.27), Emotional Aspects (PR = 4.40, 95% CI = 3.35–5.78), Mental Health domains (PR = 1.37, 95% CI = 1.06–1.68), Physical Component (PR = 2.35, 95% CI = 1.90–2.90) and Mental Component (PR = 2.65, 95% CI = 2.14–3.29). These results highlighted that master athletes showed a high SI prevalence, primarily in the lower limbs. PA positively correlates with the physical HRQoL domain, whereas SI may decrease the HRQoL levels of both physical and mental domains.  相似文献   
48.
The purpose of this study was to compare the pedalling technique in road cyclists of different competitive levels. Eleven professional, thirteen elite and fourteen club cyclists were assessed at the beginning of their competition season. Cyclists’ anthropometric characteristics and bike measurements were recorded. Three sets of pedalling (200, 250 and 300 W) on a cycle ergometer that simulated their habitual cycling posture were performed at a constant cadence (~90 rpm), while kinetic and kinematic variables were registered. The results showed no differences on the main anthropometric variables and bike measurements. Professional cyclists obtained higher positive impulse proportion (1.5–3.3% and P < 0.05), mainly due to a lower resistive torque during the upstroke (15.4–28.7% and P < 0.05). They also showed a higher ankle range of movement (ROM, 1.1–4.0° and P < 0.05). Significant correlations (P < 0.05) were found between the cyclists’ body mass and the kinetic variables of pedalling: positive impulse proportion (r = ?0.59 to ?0.61), minimum (r = ?0.59 to ?0.63) and maximum torques (r = 0.35–0.47). In conclusion, professional cyclists had better pedalling technique than elite and club cyclists, because they opted for enhancing pulling force at the recovery phase to sustain the same power output. This technique depended on cycling experience and level of expertise.  相似文献   
49.
ABSTRACT

The objective of this study was to create a valid, self-reported, game-specific soccer competence scale. A structural model of perceived competence, performance measures and motivation was tested as the basis for the scale. A total of 1321 soccer players (261 females, 1060 males) ranging from 12 to 15 years (13.4 ± 1.0 years) participated in the study. They completed the Perceived Game-Specific Soccer Competence Scale (PGSSCS), self-assessments of tactical skills and motivation, as well as technical and speed and agility tests. Results of factor analyses, tests of internal consistency and correlations between PGSSCS subscales, performance measures and motivation supported the reliability and validity of the PGSSCS. The scale can be considered a suitable instrument to assess perceived game-specific competence among young soccer players.  相似文献   
50.
The objective of the present study was to investigate the effects of combined training without caloric restriction on inflammatory markers in overweight girls. Thirty-three girls (13–17 years) were assigned into overweight training (n = 17) or overweight control (n = 16) groups. Additionally, a normal-weight group (n = 15) was used as control for the baseline values. The combined training programme consisted of six resistance exercises (three sets of 6–10 repetitions at 60–70% 1 RM) followed by 30 min of aerobic exercise (walking/running) at 50–80% VO2peak, performed in the same 60 min session, 3 days/weeks, for 12 weeks. Body composition, dietary intake, aerobic fitness (VO2peak), muscular strength (1 RM), glycaemia, insulinemia, lipid profile and inflammatory markers (C-reactive protein, interleukin-6, tumour necrosis factor-alpha, interleukin-10, leptin, resistin and adiponectin) were measured before and after intervention. There was a significant decrease in body fat (< 0.01) and increase in fat-free mass (< 0.01), VO2peak (< 0.01), 1 RM for leg press (< 0.01) and bench press (< 0.01) in the overweight training group. Concomitantly, this group presented significant decreases in serum concentrations of C-reactive protein (< 0.05) and leptin (< 0.05), as well as in insulin resistance (< 0.05) after the experimental period. In conclusion, 12 weeks of combined training without caloric restriction reduced inflammatory markers associated with obesity in overweight girls.  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