全文获取类型
收费全文 | 19172篇 |
免费 | 283篇 |
国内免费 | 23篇 |
专业分类
教育 | 13491篇 |
科学研究 | 2153篇 |
各国文化 | 230篇 |
体育 | 1425篇 |
综合类 | 19篇 |
文化理论 | 217篇 |
信息传播 | 1943篇 |
出版年
2022年 | 120篇 |
2021年 | 186篇 |
2020年 | 282篇 |
2019年 | 403篇 |
2018年 | 565篇 |
2017年 | 586篇 |
2016年 | 572篇 |
2015年 | 360篇 |
2014年 | 501篇 |
2013年 | 3555篇 |
2012年 | 436篇 |
2011年 | 441篇 |
2010年 | 412篇 |
2009年 | 378篇 |
2008年 | 421篇 |
2007年 | 402篇 |
2006年 | 374篇 |
2005年 | 342篇 |
2004年 | 366篇 |
2003年 | 317篇 |
2002年 | 341篇 |
2001年 | 392篇 |
2000年 | 425篇 |
1999年 | 342篇 |
1998年 | 192篇 |
1997年 | 245篇 |
1996年 | 237篇 |
1995年 | 192篇 |
1994年 | 200篇 |
1993年 | 171篇 |
1992年 | 267篇 |
1991年 | 263篇 |
1990年 | 282篇 |
1989年 | 265篇 |
1988年 | 219篇 |
1987年 | 255篇 |
1986年 | 223篇 |
1985年 | 273篇 |
1984年 | 216篇 |
1983年 | 204篇 |
1982年 | 183篇 |
1981年 | 170篇 |
1980年 | 155篇 |
1979年 | 230篇 |
1978年 | 197篇 |
1977年 | 160篇 |
1976年 | 128篇 |
1975年 | 136篇 |
1974年 | 124篇 |
1973年 | 128篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Victoria A. Roach Graham M. Fraser James H. Kryklywy Derek G.V. Mitchell Timothy D. Wilson 《Anatomical sciences education》2019,12(1):32-42
Research suggests that spatial ability may predict success in complex disciplines including anatomy, where mastery requires a firm understanding of the intricate relationships occurring along the course of veins, arteries, and nerves, as they traverse through and around bones, muscles, and organs. Debate exists on the malleability of spatial ability, and some suggest that spatial ability can be enhanced through training. It is hypothesized that spatial ability can be trained in low-performing individuals through visual guidance. To address this, training was completed through a visual guidance protocol. This protocol was based on eye-movement patterns of high-performing individuals, collected via eye-tracking as they completed an Electronic Mental Rotations Test (EMRT). The effects of guidance were evaluated using 33 individuals with low mental rotation ability, in a counterbalanced crossover design. Individuals were placed in one of two treatment groups (late or early guidance) and completed both a guided, and an unguided EMRT. A third group (no guidance/control) completed two unguided EMRTs. All groups demonstrated an increase in EMRT scores on their second test (P < 0.001); however, an interaction was observed between treatment and test iteration (P = 0.024). The effect of guidance on scores was contingent on when the guidance was applied. When guidance was applied early, scores were significantly greater than expected (P = 0.028). These findings suggest that by guiding individuals with low mental rotation ability “where” to look early in training, better search approaches may be adopted, yielding improvements in spatial reasoning scores. It is proposed that visual guidance may be applied in spatial fields, such as STEMM (science, technology, engineering, mathematics and medicine), surgery, and anatomy to improve student's interpretation of visual content. Anat Sci Educ. © 2018 American Association of Anatomists. 相似文献
102.
103.
K. S. Yakovlev D. A. Makarov E. S. Baskin 《Scientific and Technical Information Processing》2015,42(5):347-358
In the article we solve path planning task for an agent being multirotor unmanned aerial vehicle (multicopter). We propose an approach of estimating path geometry constraints based on UAV flight dynamics model and control constraints. Than we introduce a new path finding method which takes into consideration those geometry constraints and study this method both theoretically and empirically. 相似文献
104.
105.
Leonardo S. Fortes Dalton De Lima-Junior Lenamar Fiorese José R. A. Nascimento-Júnior Arnaldo L. Mortatti Maria E. C. Ferreira 《Journal of sports sciences》2020,38(5):552-558
ABSTRACTThe objective of this study was to analyse the effect of the use of social networks in smartphones or playing video games on the passing decision-making performance in professional soccer athletes. Participants were 25 male professional soccer athletes (mean ± SD: age 23.4 ± 2.8 years). The participants performed three randomised conditions divided into three groups: control (CON), smartphone (SMA), and video game (VID). Before and after each experimental condition, the Stroop Task assessed the level of induced mental fatigue. Then, the athletes performed a simulated soccer match. A CANON® camera recorded the matches for further analysis on passing decision-making performance. A group effect was identified (p < .01) with impairment on passing decision-making performance for the SMA (p = .01, ES = 0.5) and VID (p = .01, ES = 0.5) conditions. We concluded that the use of social networks on smartphones and/or playing video games right before official soccer matches might impair the passing decision-making performance in professional soccer athletes. 相似文献
106.
107.
108.
ABSTRACTRecently, there has been much controversy over the International Association of Athletics Federation (IAAF) regulations regarding eligibility to compete and natural testosterone levels in female athletes. Much interest lies in the analysis of Caster Semenya's extraordinary performance. The objective of this work were, a) Complete an analysis of Caster Semenya's results during the 800m finals and b) search for existing similar performances by other female athletes. We analysed the results of the finals of all IAAF World Championships and Olympic Games from 1984–2016, including the 800m results of the Diamond Leagues 2016–2018. Exponential curves were fit to the data to characterise and predict performance for each event. Caster Semenya's finishing times before her ineligibility to compete and after the suspension of the IAAF hyperandrogenism regulation were found to be 1.24% and 1.49%, respectively, faster than the characteristic performance of the elite-standard in the women’s 800m final. Other female athletes, with finishing times faster than the ones predicted by the characteristic curves were also discovered. The percentage difference in performance between Caster Semenya and the other participants did not reach 3% in the 800m event. No conclusions can be drawn regarding extraordinary results ever performed during the 100m, 200m or 400m finals. 相似文献
109.
Richard Michael Page Ben Langley Mitchell James Finlay Matt Greig Christopher Brogden 《Journal of sports sciences》2020,38(5):568-575
ABSTRACTThis study aimed to assess the effect of playing surface (Natural [NT] and Artificial [AT] Turf) on the fatigue response to a soccer-specific exercise protocol (SSEP). Eighteen male soccer players completed the SSEP on NT and AT with pre-, post-, and 48 h post-assessments of eccentric knee flexor (eccKF) and concentric knee extensor peak torque (PT), peak countermovement (CMJ) and squat jump (SJ) height, and Nordic hamstring break angle. No significant main effects for surface or any surface and time interactions were observed for any of the outcome measures, except for eccKF PT recorded at 3.14 rad·s-1, which was significantly lower 48 h post-trial in the AT condition (AT = 146.3 ± 20.4 Nm; NT = 158.8 ± 24.7 Nm). Main effects for time were observed between pre- and post-trial measures for eccKF PT at all angular velocities, Nordic break angle, CMJ and SJ height. Nordic break angle, and both CMJ and SJ height were significantly impaired 48 h post-trial when compared to pre-trial. The findings of the current study suggest surface dependent changes in eccKF PT which may have implications for recovery and subsequent performance after competition on AT. 相似文献
110.