全文获取类型
收费全文 | 18876篇 |
免费 | 338篇 |
国内免费 | 53篇 |
专业分类
教育 | 13782篇 |
科学研究 | 1291篇 |
各国文化 | 243篇 |
体育 | 1597篇 |
综合类 | 45篇 |
文化理论 | 125篇 |
信息传播 | 2184篇 |
出版年
2022年 | 124篇 |
2021年 | 222篇 |
2020年 | 341篇 |
2019年 | 518篇 |
2018年 | 705篇 |
2017年 | 711篇 |
2016年 | 712篇 |
2015年 | 463篇 |
2014年 | 578篇 |
2013年 | 3991篇 |
2012年 | 543篇 |
2011年 | 555篇 |
2010年 | 471篇 |
2009年 | 465篇 |
2008年 | 482篇 |
2007年 | 447篇 |
2006年 | 460篇 |
2005年 | 397篇 |
2004年 | 278篇 |
2003年 | 285篇 |
2002年 | 238篇 |
2001年 | 368篇 |
2000年 | 284篇 |
1999年 | 246篇 |
1998年 | 148篇 |
1997年 | 146篇 |
1996年 | 165篇 |
1995年 | 146篇 |
1994年 | 159篇 |
1993年 | 135篇 |
1992年 | 210篇 |
1991年 | 206篇 |
1990年 | 240篇 |
1989年 | 208篇 |
1988年 | 172篇 |
1987年 | 175篇 |
1986年 | 179篇 |
1985年 | 173篇 |
1984年 | 172篇 |
1983年 | 150篇 |
1982年 | 118篇 |
1981年 | 139篇 |
1980年 | 116篇 |
1979年 | 178篇 |
1978年 | 154篇 |
1977年 | 104篇 |
1976年 | 114篇 |
1975年 | 104篇 |
1973年 | 97篇 |
1971年 | 103篇 |
排序方式: 共有10000条查询结果,搜索用时 234 毫秒
1.
2.
ABSTRACTFor librarians at the University of North Florida, there was a need to move beyond information literacy instruction to one-on-one and small group research consultations to aid in student success. By staffing the research desk with staff and students, librarians were able to open their calendars to allow more time for in-person, phone, and online consultations to aid in meeting the research goals of students at the institution. After assessing the research consultation program for two years, there has been a positive correlation between research consultation usage, satisfaction in completing assignments, and student success measures throughout the university. 相似文献
3.
Daniel H. Mansson 《Communication Research Reports》2020,37(1-2):1-10
ABSTRACTThe purpose of this study was to examine the relationships between grandparents’ use of relational maintenance behaviors (RMB) and their young adult grandchildren’s willingness to serve as future caregivers for their grandparents. Undergraduate students (N = 209) completed a questionnaire in which they reported on a specific grandparent’s use of RMB and how willing they were to serve as future caregivers for that specific grandparent. Results of a multiple regression analysis provided partial support for the hypothesized positive relationships between grandparents’ use of RMB and grandchildren’s willingness to serve as future caregivers for their grandparents. 相似文献
4.
5.
Mikhail Santos Cerqueira Jose Diego Sales Do Nascimento Daniel Germano Maciel Jean Artur Mendonca Barboza Wouber Herickson De Brito Vieira 《运动与健康科学(英文)》2020,9(2):152-159
Purpose:To investigate whether blood flow restriction(BFR) without concomitant exercise mitigated strength reduction and atrophy of thigh muscles in subjects under immobilization for lower limbs.Methods:The following databases were searched:PubMed,CINAHL,PEDro,Web of Science,Central,and Scopus.Results:The search identified 3 eligible studies,and the total sample in the identified studies consisted of 38 participants.Isokinetic and isometric torque of the knee flexors and extensors was examined in 2 studies.Cross-sectional area of thigh muscles was evaluated in 1 study,and thigh girth was measured in 2 studies.The BFR protocol was 5 sets of 5 min of occlusion and 3 min of free flow,twice daily for approximately 2 weeks.As a whole,the included studies indicate that BFR without exercise is able to minimize strength reduction and muscular atrophy after immobilization.It is crucial to emphasize,however,that the included studies showed a high risk of bias,especially regarding allocation concealment,blinding of outcome assessment,intention-to-treat analyses,and group similarity at baseline.Conclusion:Although potentially useful,the high risk of bias presented by original stodies limits the indication of BFR without concomitant exercise as an effective countermeasure against strength reduction and atrophy mediated by immobilization. 相似文献
6.
使用自行设计的实验装置,对超高含水原油的流动特性和初始沉积过程进行探究。系统研究实验温度、混合流速和体积含水率对超高含水原油初始沉积过程的影响,分析不同温度下原油的运动形态和初始沉积方式。初始沉积过程可分为蔓延沉积过程和粘连沉积过程,根据沉积特点和压降曲线的变化趋势将初始沉积过程分为3个阶段:沉积诱导期、快速沉积期和沉积动态平衡期。通过对沉积物碳数分布的分析,得知超高含水原油初始沉积过程中,同时存在剪切剥离作用、胶凝作用和分子扩散作用。实验温度和体积含水率主要通过改变胶凝作用和分子扩散来影响初始沉积过程,混合流速通过改变剪切剥离强度来影响初始沉积过程。 相似文献
7.
传统遥感卫星图像处理采用在地面进行目标检测和跟踪处理的模式,卫星将拍摄到的图像数据下传至地面数据处理中心,由地面数据处理系统对接收到的遥感图像数据进行目标检测和跟踪。然而,随着遥感图像分辨率的不断提高,需要下传的数据量增大,导致星地数据传输的时间大大增加,最终造成目标检测和跟踪的时效性降低。针对上述问题,提出一种基于多特征量判别的Canny边缘检测和联合概率数据关联的在轨海上多运动舰船目标检测和跟踪方法。将该方法利用中国科学院微小卫星创新研究院的高分微纳卫星实测数据在模拟星载的嵌入式开发平台上进行验证,结果表明该方法能够在轨对海上多运动舰船目标进行快速、准确的检测和跟踪。 相似文献
8.
Continued advancement in the field of physical activity and health promotion relies heavily on the synthesis of rigorous scientific evidence. As such, systematic reviews and meta-analyses of randomized controlled trials have led to a better understanding of which intervention strategies are superior (i.e., produce the greatest effects) in physical activity-based health behavior change interventions. Indeed, standard meta-analytic approaches have allowed researchers in the field to synthesize relevant experimental evidence using pairwise procedures that produce reliable estimates of the homogeneity, magnitude, and potential biases in the observed effects. However, pairwise meta-analytic procedures are only capable to discerning differences in effects between a select intervention strategy and a select comparison or control condition. In order to maximize the impact of physical activity interventions on health-related outcomes, it is necessary to establish evidence concerning the comparative efficacy of all relevant physical activity intervention strategies. The development of network meta-analysis (NMA)—most commonly used in medical-based clinical trials—has allowed for the quantification of indirect comparisons, even in the absence of direct, head-to-head trials. Thus, it stands to reason that NMA can be applied in physical activity and health promotion research to identify the best intervention strategies. Given that this analysis technique is novel and largely unexplored in the field of physical activity and health promotion, care must be taken in its application to ensure reliable estimates and discernment of the effect sizes among interventions. Therefore, the purpose of this review is to comment on the potential application and importance of NMA in the field of physical activity and health promotion, describe how to properly and effectively apply this technique, and suggest important considerations for its appropriate application in this field. In this paper, overviews of the foundations of NMA and commonly used approaches for conducting NMA are provided, followed by assumptions related to NMA, opportunities and challenges in NMA, and a step-by-step example of developing and conducting an NMA. 相似文献
9.
Inhibitory control is the capacity to suppress inappropriate responses. It is central to many aspects of development, most notably executive function and effortful control. Despite its importance, however, there are significant gaps in our understanding of inhibitory control’s early development, and several findings that remain hard to explain. Here, a new account of inhibitory control is presented, explaining previous findings by distinguishing between two distinct ways that inhibitory control is used. According to this “Strength/Endurance” account, inappropriate responses which are highly prepotent tax inhibitory strength; whereas inappropriate responses which remain active for a long time tax inhibitory endurance. The developmental trajectories of these two aspects of inhibitory control, and their separate impacts on broader development, are discussed. 相似文献
10.
Maddison J. Jones Brian Dawson Daniel F. Gucciardi Peter R. Eastwood Joanna Miller Shona L. Halson 《Journal of sports sciences》2019,37(8):864-870
The present study aimed to investigate pre-sleep behaviours (including evening electronic device use) and sleep quantity in well-trained athletes. Seventy well-trained athletes (44 females, 26 males) aged 21 ± 4 y from a range of team and individual sports were asked to complete an online sleep diary for 7 days. The sleep diary included questions about pre-sleep behaviours (e.g. napping, caffeine intake), electronic device use in the 2 h prior to bedtime (e.g. type of device and duration of use) and sleep (e.g. time in bed, sleep onset latency). On average, athletes spent 8:20 ± 1:21 h in bed each night. Associations between age, time in bed and sleepiness suggested that younger athletes spent more time in bed (B = -0.05, p = 0.001) but felt sleepier (r = -0.32, p < 0.01) than older athletes. On average, athletes mostly used electronic devices for 0–30 min prior to sleep. The use of multiple devices in the evening was associated with more perceived difficulty in falling asleep (B = 0.22, p = 0.03), but no associations existed with other sleep variables. In summary, younger athletes may require later start times or improved sleep quality to resolve excessive sleepiness. 相似文献