全文获取类型
收费全文 | 18605篇 |
免费 | 327篇 |
国内免费 | 55篇 |
专业分类
教育 | 13662篇 |
科学研究 | 1274篇 |
各国文化 | 237篇 |
体育 | 1470篇 |
综合类 | 45篇 |
文化理论 | 106篇 |
信息传播 | 2193篇 |
出版年
2022年 | 118篇 |
2021年 | 210篇 |
2020年 | 298篇 |
2019年 | 453篇 |
2018年 | 617篇 |
2017年 | 635篇 |
2016年 | 626篇 |
2015年 | 405篇 |
2014年 | 540篇 |
2013年 | 3775篇 |
2012年 | 511篇 |
2011年 | 527篇 |
2010年 | 456篇 |
2009年 | 447篇 |
2008年 | 470篇 |
2007年 | 433篇 |
2006年 | 452篇 |
2005年 | 389篇 |
2004年 | 278篇 |
2003年 | 287篇 |
2002年 | 244篇 |
2001年 | 380篇 |
2000年 | 300篇 |
1999年 | 266篇 |
1998年 | 173篇 |
1997年 | 169篇 |
1996年 | 179篇 |
1995年 | 155篇 |
1994年 | 168篇 |
1993年 | 148篇 |
1992年 | 223篇 |
1991年 | 226篇 |
1990年 | 248篇 |
1989年 | 223篇 |
1988年 | 185篇 |
1987年 | 188篇 |
1986年 | 193篇 |
1985年 | 184篇 |
1984年 | 193篇 |
1983年 | 173篇 |
1982年 | 141篇 |
1981年 | 151篇 |
1980年 | 134篇 |
1979年 | 200篇 |
1978年 | 174篇 |
1977年 | 120篇 |
1976年 | 121篇 |
1975年 | 115篇 |
1974年 | 107篇 |
1971年 | 119篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
This paper demonstrates the application of module arithmetic for controlling the level of information security by a new technique referred as integer splitting. The basic definitions and concepts of the method are provided. The mathematical function of arising transformation is described in detail; its properties were studied and the basic theorems were proven that justify the use of splitting in practical applications. An active system was designed and characteristic cases of its operation are considered. 相似文献
102.
A Campus-Wide Investigation of Clicker Implementation: The Status of Peer Discussion in STEM Classes
Justin D. Lewin Erin L. Vinson MacKenzie R. Stetzer Michelle K. Smith 《CBE life sciences education》2016,15(1)
At the University of Maine, middle and high school teachers observed more than 250 university science, technology, engineering, and mathematics classes and collected information on the nature of instruction, including how clickers were being used. Comparisons of classes taught with (n = 80) and without (n = 184) clickers show that, while instructional behaviors differ, the use of clickers alone does not significantly impact the time instructors spend lecturing. One possible explanation stems from the observation of three distinct modes of clicker use: peer discussion, in which students had the opportunity to talk with one another during clicker questions; individual thinking, in which no peer discussion was observed; and alternative collaboration, in which students had time for discussion, but it was not paired with clicker questions. Investigation of these modes revealed differences in the range of behaviors, the amount of time instructors lecture, and how challenging the clicker questions were to answer. Because instructors can vary their instructional style from one clicker question to the next, we also explored differences in how individual instructors incorporated peer discussion during clicker questions. These findings provide new insights into the range of clicker implementation at a campus-wide level and how such findings can be used to inform targeted professional development for faculty. 相似文献
103.
Danny Bavli Elishai Ezra Daniel Kitsberg Margarita Vosk-Artzi Shashi K. Murthy Yaakov Nahmias 《Biomicrofluidics》2016,10(2)
Cell-cell interactions play a key role in regeneration, differentiation, and basic tissue function taking place under physiological shear forces. However, current solutions to mimic such interactions by micro-patterning cells within microfluidic devices have low resolution, high fabrication complexity, and are limited to one or two cell types. Here, we present a microfluidic platform capable of laminar patterning of any biotin-labeled peptide using streptavidin-based surface chemistry. The design permits the generation of arbitrary cell patterns from heterogeneous mixtures in microfluidic devices. We demonstrate the robust co-patterning of α-CD24, α-ASGPR-1, and α-Tie2 antibodies for rapid isolation and co-patterning of mixtures of hepatocytes and endothelial cells. In addition to one-step isolation and patterning, our design permits step-wise patterning of multiple cell types and empty spaces to create complex cellular geometries in vitro. In conclusion, we developed a microfluidic device that permits the generation of perfusable tissue-like patterns in microfluidic devices by directly injecting complex cell mixtures such as differentiated stem cells or tissue digests with minimal sample preparation. 相似文献
104.
105.
One of the most controversial issues in special education over the last 40 years has been the extent to which students with learning disabilities (LD) should be educated in general education classrooms. Recent mandates in federal law requiring that all students with disabilities have access to the general education curriculum and make adequate yearly progress relative to this content have intensified this debate. In this article, a brief summary of research regarding the nature of instruction that produces significantly improved educational outcomes for students with LD is provided. This is followed by a review of research related to the delivery of this high‐quality instruction in inclusive, general education classrooms and in resource settings. We conclude that this research provides the foundation for reconsidering full inclusion and how services are delivered for elementary students with LD. 相似文献
106.
107.
ABSTRACTDue to budget constraints, schools in the United States have increasingly turned to community arts organizations for support. School-community arts partnership stakeholders collaborate because of shared missions to provide students with valuable arts learning experiences. Investigations of these initiatives indicate that these partnerships improve arts learning opportunities and increase public support and resources for arts education. However, not much is known about the experiences and perspectives of the arts organizations that participate in these partnerships. Coordinating collective efforts with a multitude of institutions and interests poses challenges. In this study, we examine survey data collected from arts organization administrators who participated in a large-scale school-community arts partnership initiative. We find that these organizations are generally positive about their impacts on students’ educational outcomes, but there is substantial variation in these views. We also find that organizations differ in their levels of support for these collective efforts. Sources of this variation appear to be attributable to organizations’ preexisting resources and extent to which they are established. While this difference in levels of support is potentially inevitable, we find evidence that the operations handled by the “backbone” organization, i.e. the initiative’s facilitators and overseers, can significantly influence organizations’ levels of support for these efforts. Organizations are more likely to support these collaborative efforts when they believe the backbone organization ensures transparency with initiative operations, provides regular, effective communication, and effectively resolves competing priorities. 相似文献
108.
109.
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
110.
Annie Dupuis Maheshan Indralingam Andre Chevrier Jennifer Crosbie Paul Arnold Christie L. Burton Russell Schachar 《Child development》2019,90(2):e263-e272
Adjusting speed to maintain fast and accurate performance is critical to goal-directed behavior. This study examined development of response time adjustments in the stop signal task in 13,709 individuals aged 6–17 years (49.0% Caucasian) across four trial types: correct and incorrect go, successful (stop-inhibit), and failed (stop-respond) trials. People sped more after correct than incorrect go responses and slowed more after failed than successful stop trials. Greater slowing after stop-respond but less slowing after stop-inhibit trials was associated with better response inhibition. Response time adjustments were evident in children as young as age 6, developed throughout childhood, and plateaued by age 10. Results were consistent with the predictions of the error detection and shifting goal priority hypotheses for adjustments. 相似文献