全文获取类型
收费全文 | 30034篇 |
免费 | 478篇 |
国内免费 | 22篇 |
专业分类
教育 | 21220篇 |
科学研究 | 2986篇 |
各国文化 | 305篇 |
体育 | 2403篇 |
综合类 | 25篇 |
文化理论 | 249篇 |
信息传播 | 3346篇 |
出版年
2022年 | 196篇 |
2021年 | 345篇 |
2020年 | 488篇 |
2019年 | 783篇 |
2018年 | 1078篇 |
2017年 | 1023篇 |
2016年 | 895篇 |
2015年 | 548篇 |
2014年 | 818篇 |
2013年 | 5885篇 |
2012年 | 809篇 |
2011年 | 818篇 |
2010年 | 633篇 |
2009年 | 609篇 |
2008年 | 677篇 |
2007年 | 607篇 |
2006年 | 558篇 |
2005年 | 561篇 |
2004年 | 541篇 |
2003年 | 518篇 |
2002年 | 479篇 |
2001年 | 635篇 |
2000年 | 522篇 |
1999年 | 460篇 |
1998年 | 274篇 |
1997年 | 269篇 |
1996年 | 281篇 |
1995年 | 275篇 |
1994年 | 209篇 |
1993年 | 254篇 |
1992年 | 383篇 |
1991年 | 371篇 |
1990年 | 371篇 |
1989年 | 364篇 |
1988年 | 303篇 |
1987年 | 367篇 |
1986年 | 322篇 |
1985年 | 377篇 |
1984年 | 305篇 |
1983年 | 278篇 |
1982年 | 244篇 |
1981年 | 219篇 |
1980年 | 195篇 |
1979年 | 321篇 |
1978年 | 255篇 |
1977年 | 223篇 |
1976年 | 192篇 |
1975年 | 176篇 |
1974年 | 188篇 |
1973年 | 163篇 |
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
1.
Research in Higher Education - Given the significant need to increase and diversify graduate enrollments within computing fields, it is vital to understand what shapes students’ pathways to... 相似文献
2.
David Sánchez-Oliva Rebecca M. Leech Alberto Grao-Cruces Irene Esteban-Cornejo Carmen Padilla-Moledo Oscar L. Veiga 《Journal of sports sciences》2020,38(9):1062-1069
ABSTRACTThe 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
3.
4.
Cultural Studies of Science Education - The retention of underrepresented students remains a significant challenge in the STEM (Science, Technology, Engineering and Math) disciplines. A broad range... 相似文献
5.
Piret Luik Reelika Suviste Marina Lepp Tauno Palts Eno Tõnisson Merilin Säde Kaspar Papli 《British journal of educational technology : journal of the Council for Educational Technology》2019,50(1):153-165
Learners who enrol in massive open online courses (MOOCs) have different backgrounds and tend to have different motivations than learners in traditional courses. Based on value-expectancy theory, an instrument was developed to measure motivation for enrolling in a programming MOOC. A study with 1229 adult participants in Estonian-language programming course “About Programming” was conducted to validate the instrument. Results of confirmatory factor analysis validated the 7-factor scale named factors influencing enrolment in MOOC (FIEM). FIEM comprises three factors of expectancies, three factors of values and one factor of social influence. The highest and lowest rated motivational factors influencing enrolment in programming MOOC are discussed in the paper. Interest in and expectations for the course, personal suitability of distance learning and suitability for family and work are the highest-rated motivational factors for those who enrol in MOOC. Usefulness related to own children, social influence and usefulness to related to certification were the lowest rated. The results of this study can be useful for designers of programming MOOCs and the developed scale might be used in future studies. 相似文献
6.
7.
8.
Digital Module 05: Diagnostic Measurement—The G‐DINA Framework https://ncme.elevate.commpartners.com
In this ITEMS module, we introduce the generalized deterministic inputs, noisy “and” gate (G‐DINA) model, which is a general framework for specifying, estimating, and evaluating a wide variety of cognitive diagnosis models. The module contains a nontechnical introduction to diagnostic measurement, an introductory overview of the G‐DINA model, as well as common special cases, and a review of model‐data fit evaluation practices within this framework. We use the flexible GDINA R package, which is available for free within the R environment and provides a user‐friendly graphical interface in addition to the code‐driven layer. The digital module also contains videos of worked examples, solutions to data activity questions, curated resources, a glossary, and quizzes with diagnostic feedback. 相似文献
9.
Harry F. Dorrell Joseph M. Moore Mark F. Smith Thomas I. Gee 《Journal of sports sciences》2019,37(1):67-73
This study investigated the validity and reliability of the GymAware PowerTool (GPT). Thirteen resistance trained participants completed three visits, consisting of three repetitions of free-weight back squat, bench press, deadlift (80% one repetition maximum), and countermovement jump. Bar displacement, peak and mean velocity, peak and mean force, and jump height were calculated using the GPT, a three-dimensional motion capture system (Motion Analysis Corporation; 150 Hz), and a force plate (Kistler; 1500 Hz). Least products regression were used to compare agreeability between devices. A within-trial one-way ANOVA, typical error (TE; %), and smallest worthwhile change (SWC) were used to assess reliability. Regression analysis resulted in R2 values of >0.85 for all variables excluding deadlift mean velocity (R2 = 0.54–0.69). Significant differences were observed between visits 3-2 for bench press bar displacement (0.395 ± 0.055 m; 0.383 ± 0.053 m), and deadlift bar displacement (0.557 ± 0.034 m; 0.568 ± 0.034 m). No other significant differences were found. Low to moderate TE (0.6–8.8%) were found for all variables, with SWC ranging 1.7–7.4%. The data provides evidence that the GPT can be used to measure kinetic and kinematic outputs, however, care should be taken when monitoring deadlift performance. 相似文献
10.
ABSTRACTThe preservation of artefacts in museum collections is profoundly affected by fluctuations in temperature and, especially, relative humidity (RH). Since the late nineteenth century, many studies have been carried out on the best way to control hygrothermal conditions. In old buildings located in maritime temperate climate zones (such as Portugal) with strong thermal inertia, and which have low ventilation rate (relative to the volume and number of visitors), daily and seasonal hygroscopic inertia may help to assure the maintenance of RH stabilization conditions. The use of expensive active systems may be minimized through the passive behaviour of internal finishing building materials. This work presents the results of an experimental laboratory study conducted in a flow chamber to demonstrate the enormous potential of hygroscopic materials in stabilizing interior relative humidity. Based in these results and in-situ monitoring in a museum housed in a building, located in Porto, with a typical construction of the 1950s (granite masonry and reinforced concrete slabs), a numerical analysis was done to quantify the influence of hygroscopic materials in stabilizing the interior relative humidity. 相似文献