全文获取类型
收费全文 | 2181篇 |
免费 | 62篇 |
国内免费 | 4篇 |
专业分类
教育 | 1601篇 |
科学研究 | 85篇 |
各国文化 | 28篇 |
体育 | 184篇 |
综合类 | 1篇 |
文化理论 | 19篇 |
信息传播 | 329篇 |
出版年
2023年 | 22篇 |
2022年 | 26篇 |
2021年 | 31篇 |
2020年 | 79篇 |
2019年 | 112篇 |
2018年 | 138篇 |
2017年 | 157篇 |
2016年 | 128篇 |
2015年 | 80篇 |
2014年 | 105篇 |
2013年 | 474篇 |
2012年 | 66篇 |
2011年 | 71篇 |
2010年 | 51篇 |
2009年 | 58篇 |
2008年 | 70篇 |
2007年 | 42篇 |
2006年 | 50篇 |
2005年 | 47篇 |
2004年 | 39篇 |
2003年 | 46篇 |
2002年 | 24篇 |
2001年 | 17篇 |
2000年 | 21篇 |
1999年 | 18篇 |
1998年 | 13篇 |
1997年 | 10篇 |
1996年 | 14篇 |
1995年 | 10篇 |
1994年 | 10篇 |
1993年 | 16篇 |
1992年 | 15篇 |
1991年 | 9篇 |
1990年 | 11篇 |
1989年 | 11篇 |
1988年 | 17篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 8篇 |
1982年 | 6篇 |
1981年 | 7篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1977年 | 6篇 |
1976年 | 7篇 |
1973年 | 7篇 |
1971年 | 4篇 |
1970年 | 4篇 |
1968年 | 7篇 |
排序方式: 共有2247条查询结果,搜索用时 15 毫秒
981.
Heather P. Eastman-Mueller Jessica R. Gomez-Scott Ae-Kyung Jung Kristofer Hagglund 《American journal of sexuality education》2016,11(3):189-204
The U.S. Centers for Disease Control and Prevention advocate access to condoms as a critical sexual health prevention strategy. The purpose of this article is to discuss the implementation and evaluation of a condom availability program using dispensing machines in residence halls at a Midwestern U.S. university. Undergraduate students (N = 337) living in on-campus housing participated in a survey about their utilization of condom dispensers at the beginning and end of three academic years (2008–2009, 2009–2010, and 2010–2011). Questions also addressed students' attitudes toward the condom dispensers and related sexual behavior. Results indicated that the presence of condom machines did not increase rates of sexual activity (a concern of university administrators), but there was also no improvement in rates of unprotected sex. Overall, students reported high levels of satisfaction with the condom availability program. Implementation challenges are discussed and recommendations for universities and colleges wishing to execute similar programs are provided. 相似文献
982.
Oliver Joseph Steve Hodges Georgia W. Moore James N. Cohen Allan Jang Yoonsun Brown Scott A. Kwon Kyung A. Jeong Sophia Raven Sara P. Jurkiewicz Melissa Robertson Tom P. 《Research in Science Education》2019,49(6):1783-1808
Research in Science Education - Research into the efficacy of modules featuring dynamic visualizations, case studies, and interactive learning environments is reported here. This quasi-experimental... 相似文献
983.
Jessica Gale Stefanie Wind Jayma Koval Joseph Dagosta Mike Ryan Marion Usselman 《International Journal of Science Education》2016,38(14):2284-2302
This paper illustrates the use of simulation-based performance assessment (PA) methodology in a recent study of eighth-grade students’ understanding of physical science concepts. A set of four simulation-based PA tasks were iteratively developed to assess student understanding of an array of physical science concepts, including net force, acceleration, velocity, and inertia. Illustrative examples drawn from the administration of these simulation-based PA tasks to a sample of eighth-grade students (n?=?74) highlight the potential of simulation-based tasks for revealing conceptual understanding of science concepts and for informing curriculum development within the context of design-based implementation research. The paper also describes a variety of challenges encountered over the course of the development, administration, and analysis of the PA data that may be informative for researchers and educators as they consider implementing simulation-based PAs. 相似文献
984.
Jeremiah Chin Nicholas Bustamante Jessica Ann Solyom Bryan McKinley Jones Brayboy 《理论付诸实践》2016,55(1):28-38
In 2007, the Cherokee Nation of Oklahoma amended its constitution to limit membership to only those who can trace lineal descent to an individual listed as Cherokee by Blood on the final Dawes Rolls. This exercise of sovereignty paradoxically ties the Dawes Rolls, the colonial instruments used to divide the lands and peoples of the Cherokee Nation, and self-determination. In the process, it effectively disenrolls Cherokee Freedmen, the descendants of Blacks enslaved by the Cherokee Nation. In this article, we explore the implications of this history in the context of self-determination and sovereignty, particularly looking at the influence of colorism on the Dawes Rolls and its ongoing effects. Our goal is to share a piece of history that is often obscured or unknown; to explore how and to what extent the exercise of self-determination and sovereignty in Indigenous nations is impacted by colorism; and finally to consider implications for practice created by the disenfranchisement of peoples from Indigenous nations. 相似文献
985.
986.
Ric Lovell Jason C. Siegler Michael Knox Scott Brennan Paul W. M. Marshall 《Journal of sports sciences》2016,34(24):2286-2294
ABSTRACTThe optimal scheduling of Nordic Hamstring exercises (NHEs) relative to football training sessions is unknown. We examined the acute neuromuscular and performance responses to NHE undertaken either before (BT) or after (AT) simulated football training. Twelve amateur players performed six sets of five repetitions of the NHE either before or after 60 min of standardised football-specific exercise (SAFT60). Surface electromyography signals (EMG) of the hamstring muscles were recorded during both the NHE, and maximum eccentric actions of the knee flexors (0.52 rad · s–1) performed before and after the NHE programme, and at 15 min intervals during SAFT60. Ten-metre sprint times were recorded on three occasions during each 15 min SAFT60 segment. Greater eccentric hamstring fatigue following the NHE programme was observed in BT versus AT (19.8 %; very likely small effect), which was particularly apparent in the latter range of knee flexion (0–15°; 39.6%; likely moderate effect), and synonymous with hamstring EMG declines (likely small–likely moderate effects). Performing NHE BT attenuated sprint performance declines (2.0–3.2%; likely small effects), but decreased eccentric hamstring peak torque (–14.1 to –18.9%; likely small effects) during football-specific exercise. Performing NHE prior to football training reduces eccentric hamstring strength and may exacerbate hamstring injury risk. 相似文献
987.
988.
Background: There is a high incidence of concussion sustained by athletes participating in rugby union, many of which go unreported. A lack of sufficient knowledge about concussion injuries may explain athletes’ failure to report. Several rugby union-playing countries have developed injury education and prevention programmes to address this issue. Objective: The aim of the current review was to systematically assess the content and level of evidence on concussion education/prevention programmes in rugby union and to make recommendations for the quality, strength, and consistency of this evidence. Methods: We searched PubMed, PsycInfo, MEDLINE, SPORTDiscuss, Webofscience, and conducted a manual search for articles. Results: Ten articles were included for review. Of these, six focused on the BokSmart injury prevention programme in South Africa, two focused on the RugbySmart injury prevention programme in New Zealand, one was an analysis of prevention programmes, and one was a systematic review of rugby injury prevention strategies. Conclusions: Despite the initiative to develop concussion education and prevention programmes, there is little evidence to support the effectiveness of such programmes. There is evidence to support education of coaches and referees. In addition, there is scant evidence to suggest that education and rule changes may have the benefit of changing athlete behaviours resulting in a reduction in catastrophic injury. 相似文献
989.
Ryan S. McGinnis Stephen M. Cain Steven P. Davidson Rachel V. Vitali Noel C. Perkins Scott G. McLean 《Sports Engineering》2016,19(1):21-34
We present a method for quantifying sacral kinematics during countermovement jumping (CMJ) using an inertial measurement unit (IMU). The IMU-derived sacral kinematic trajectories reproduced motion capture acceleration, velocity, and displacement to within mean (standard deviation) differences of 0.024 (0.088) m/s2, 0.023 (0.026) m/s, and 0.003 (0.032) m, respectively, across 252 jumps performed by 14 subjects. The method also quantified differences in maximum sacral displacement to within 1 % and differences in maximum propulsive velocity to within 0.7 % of motion capture estimates. This builds upon existing IMU-based methods for quantifying jump performance, which do not provide sacral kinematic trajectories. The utility of this method is demonstrated by its ability to discriminate jump performance metrics across a diverse subject population. In particular, we found that 21 participants adopted multiple strategies to maximize jump height in unloaded and loaded fresh conditions, but converged to a common strategy when jumping fatigued and under load. Changes in kinematic parameters were evident across conditions, and several changes were significantly associated with changes in jump performance (i.e., height). These parameters include changes in the depth of the countermovement, duration of the propulsive phase and maximum propulsive velocity. Collectively, these results point toward the future use of this method in naturalistic environments and for multiple objectives including biomechanical performance assessment and tracking, fatigue assessment, and jump training. 相似文献
990.
Nasim Daemi Scott Henning James Gibert Philip Yuya Goodarz Ahmadi 《Sports Engineering》2016,19(1):35-46
This paper seeks to address the implications on putting a golf ball with an off-center mass by analyzing the effect of unbalanced mass of ball on its impact and subsequent rolling. We present the general formulation of a rigid golf ball rolling with slip that is able to transition to rolling friction on an arbitrary surface. Particular attention is given to the effects of the offset center of mass on the golf ball’s path. An experimental setup based on a USGA Stimpmeter is used to calibrate the position of contact point as the ball rolls on the green. The trajectories of the ball due to the mass imbalance were studied by numerically solving the equations of motion during putting. Theoretical predictions show that a mass imbalance has little effect on the launch conditions of the ball. However, on a level green a mass offset center of 0.2 % of the ball’s radius can impact the path of the ball with the consequences of missing the hole in a 5.8 m putt. Changing golf ball trajectories with mass offset center has implications on the development of balls and putting. 相似文献