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   2230篇
  免费   31篇
  国内免费   1篇
教育   1626篇
科学研究   132篇
各国文化   21篇
体育   280篇
文化理论   55篇
信息传播   148篇
  2023年   21篇
  2022年   45篇
  2021年   66篇
  2020年   99篇
  2019年   183篇
  2018年   195篇
  2017年   188篇
  2016年   158篇
  2015年   104篇
  2014年   86篇
  2013年   503篇
  2012年   70篇
  2011年   65篇
  2010年   53篇
  2009年   40篇
  2008年   26篇
  2007年   34篇
  2006年   33篇
  2005年   22篇
  2004年   19篇
  2003年   24篇
  2002年   13篇
  2001年   14篇
  2000年   12篇
  1999年   14篇
  1998年   9篇
  1997年   8篇
  1996年   11篇
  1995年   10篇
  1994年   9篇
  1993年   10篇
  1992年   8篇
  1991年   9篇
  1990年   13篇
  1989年   4篇
  1988年   3篇
  1987年   8篇
  1986年   8篇
  1985年   7篇
  1984年   3篇
  1981年   5篇
  1980年   4篇
  1979年   6篇
  1978年   7篇
  1977年   5篇
  1976年   4篇
  1974年   2篇
  1973年   3篇
  1970年   3篇
  1963年   3篇
排序方式: 共有2262条查询结果,搜索用时 15 毫秒
81.
The purpose of this study was to analyse associations between lean soft tissue (LST), a surrogate of skeletal muscle mass and key fracture-related geometric characteristics of the proximal femur. Moreover, we examined the role that muscle played on the proximal femur geometry in response to physical activity (PA). Participants were 83 young adults. Leg LST (exposure) was assessed by dual energy X-ray absorptiometry (DXA). Proximal femur geometry was derived from a left hip DXA scan. Geometric variables (outcomes) included the femoral neck axis length (FNAL), the femoral neck width (FNW), the neck–shaft angle and FNW|FNAL (an index of robustness). PA was evaluated by accelerometry. Linear regression was used to analyse relationships. Additional exposure variables included body height and mass. In males, leg LST explained 17.4% of variation in FNAL (P < 0.001) and 15% in FNW (P = 0.015). In females, it explained 8.8% of the variance in FNAL (P = 0.020). Associations remained significant in males, but not in females, when vigorous PA was added to the models. These results suggest that public health approaches to promote PA may be particularly important in females since vigorous PA seems to convey advantages in femur geometry and consequently in bone strength.  相似文献   
82.
The purpose of this study was to examine the effects of a 10 week contrast training (CT) programme (isometric + plyometric) on jumping, sprinting abilities and agility performance in prepubertal basketball players. Fifty-eight children from a basketball academy (age: 8.72 ± 0.97 years; body mass index: 17.22 ± 2.48 kg/m2) successfully completed the study. Participants were randomly assigned to experimental groups (EG, n = 30) and control groups (CG, n = 28). The CT programme was included in the experimental group’s training sessions – twice a week – as part of their usual weekly training regime. This programme included 3 exercises: 1 isometric and 2 plyometric. Jumping, sprinting and agility performance were assessed before and after the training programme. Significant differences were found in posttest between EG and CG in sprint and T-test: EG showed better results than CG. Furthermore, there were significant differences in posttest-pretest between EG and CG in squat jump, countermovement jump, drop jump, sprint and T-test with the EG showing better results than CG. The CT programme led to increases in vertical jump, sprint and agility levels, so that the authors suggest that prepubertal children exhibit high muscular strength trainability.  相似文献   
83.
ABSTRACT

The aims of this study were to identify profiles of sedentary behaviour (SB) patterns, based on leisure-time self-reported SB modalities (screen, educative, social, and relaxing) and to evaluate changes in these profiles over 2 years among Spanish youth aged 8–18 years. Latent profile analysis (LPA), a data-driven analytic approach, was used to identify groups of boys and girls (n = 1553; 48% girls; mean±SD age: 12.56 ± 2.49 y) with distinct SB profiles using the SB modalities (time/d) as input variables. Latent transition analysis, an extension of LPA that uses longitudinal data, was used to analyse 2-year changes in these profiles. At baseline, four and three SB profiles were found among boys (labelled: screen, educative, social, and relaxing) and girls (labelled: screen/social, educative, and relaxing), respectively. Overall, more girls (range: 48%-67%) had the same profile over time, than boys (40%-52%). Participants with a screen or relaxing SB profile at baseline were more likely to have an educative profile after 2 years. Youth with a social and an educative SB profile at baseline were more likely to transition to profiles characterized by higher screen and social SB, respectively. Using a novel and person-centered approach, this study identified gender-specific SB profiles that were moderately stable over time.  相似文献   
84.
This study aimed to (1) evaluate the effect of hand shaking during recovery phases of intermittent testing on the time–force characteristics of performance and muscle oxygenation, and (2) assess inter-individual variability in the time to achieve the target force during intermittent testing in rock climbers. Twenty-two participants undertook three finger flexor endurance tests at 60% of their maximal voluntary contraction until failure. Performances of a sustained contraction and two intermittent contractions, each with different recovery strategies, were analysed by time–force parameters and near-infrared spectroscopy. Recovery with shaking of the forearm beside the body led to a significantly greater intermittent test time (↑ 22%, P?P?P?相似文献   
85.
Aim was to identify critical load (CL) in young and elderly apparently healthy male cohorts. To contrast the metabolic, cardiovascular and perceptual responses on CL according to age. We evaluated 12 young (23 ± 3 years) and 10 elderly (70 ± 2 years) apparently healthy active males, who underwent: (1) 1 repetition maximum (1RM) test on a 45° Leg Press; (2) on different days, three high-intensity resistance exercise constant load tests (60%, 75% and 90% 1RM) until fatigue (Tlim). Absolute values of both the CL asymptote and curvature constant (kg) were significantly lower in elderly subjects (P < 0.05). In contrast, elderly subjects demonstrated a significantly higher number of repetitions at CL when compared with young subjects (P < 0.05). As expected, oxygen uptake (VO2) and heart rate (HR) during maximal aerobic exercise testing were significantly reduced in older subjects. However, percent-predicted aerobic capacity were higher in older subjects (P < 0.05). In addition, blood lactate ([La?]) corrected to Tlim and rating of perceived exertion values were greater in younger subjects at all intensities (P < 0.05). These findings, despite reduced force production in older subjects, endurance-related parameters are well preserved according to age-adjusted percent-predicted values in apparently healthy males.  相似文献   
86.
This study was conducted in an environment of widespread use of social media and mobile applications in the mass media. The general goal of the study was to analyze the use of WhatsApp in cybermedia, specifically in radio. A case study was proposed to examine the use of WhatsApp on the program Las mañanas de RNE, broadcast by Spanish National Radio. It was found that the public was very accepting of the program’s initiative to solicit WhatsApp voice messages, beginning in November 2015. The case study used audio files of a direct broadcast that included specific times for audience participation. The use of WhatsApp was accepted by the audience, in addition to the use of the conventional telephone, as a tool well-suited to listener participation in radio programming. Finally, the study highlights the importance of interactive, participatory spaces in broadcasts through the creation of synergies with new forms of online participation.  相似文献   
87.
Metrics on open access (OA) availability of content published in scholarly journals (i.e. content licences, copyright ownership, and publisher‐stipulated self‐archiving permissions) are still scarce. This study implements the four core variables of the recently published Open Access Spectrum (OAS) (reader rights, reuse rights, copyright, and author posting rights) to measure the level of openness in all 1,728 Spanish scholarly journals listed in the Spanish national DULCINEA database at the end of 2015. Data exported from the database and used as variables for the analysis were: journal research area, type of publisher, type of access, self‐archiving and reuse policy, and type of Creative Commons (CC) licence used. Out of the total number of journals (1,728), 1,285 (74.5%) published their articles OA immediately after initial publication and thus received the maximum OAS score for reader rights; 37.5% of all journals used CC licences, and 79.5% allowed self‐archiving in some form. In 72% of journals, authors retained or publishers granted broad rights, which included author reuse and authorization rights (for others to reuse), whilst 13.5% did not specify any terms for copyright transfer. Similar studies could be carried out on other countries as this would enable comparisons of the general adoption and form of openness in different parts of the world.  相似文献   
88.
This reflection essay describes the Central States Region as an area rich in intercultural communication. González describes Mexican American migrant farmworker organizing as an intercultural activity since the union activists attempted to influence both Mexican heritage and European heritage audiences. González also describes the many interculturalists working in the Midwest who influenced his early research.  相似文献   
89.
The old urban centres are marks of an historical and architectural heritage that should be protected and safeguarded. For such, it is fundamental to have a complete understanding of the genesis, regarding both building and the urban mesh. This fact is essential to the support of qualified, conscientious and sustainable rehabilitation interventions on the old building stock. The research carried out addresses the issue of the old urban centres from the perspective of the analysis and inventory of buildings features. The cataloguing process of the building typologies is presented in this work as a synthesis of the principal construction forms, with the old city centre of Seixal being used as a case study. The identification of building typologies has supported a seismic and fire vulnerability assessment of the old building stock. The assessment methodologies developed and used are based on the detailed survey and building inspection, therefore the building typology cataloguing is essential in the analysis at such a large scale. Then we discussed the strategy for the conservation actions incorporated in a broader risk management policy.  相似文献   
90.
This article analyses the review, acceptance and publication dates of a sample of 21,890 articles from 326 Ibero-American scientific journals from all subject areas and countries included in the Latindex Catalogue 2.0 and published between 2018 and 2020 (freely available as an open access dataset). The aim is to discover evaluation and publication times. The evaluation process takes a median of 110 days, the publication process, a median of 82 days, and the whole process, a median of 224 days. Statistical differences are found according to periodicity, subject areas, countries, existence of a printed version and article type (Call for Papers or General articles). From the data we find that the delay in publication is longer than publishers themselves report to the DOAJ. STEM areas present the most similarity in publication patterns, having a higher number of evaluation days (Ed) than publication days (Pd); Arts and Humanities present the opposite pattern, with a higher Pd than Ed. In the case of Social Sciences, the times are similar. General articles and Call for Papers articles differ in terms of Ed, but not Pd, indicating that Call for Papers revisions are faster.  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