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   1062篇
  免费   42篇
  国内免费   1篇
教育   849篇
科学研究   19篇
各国文化   12篇
体育   77篇
文化理论   5篇
信息传播   143篇
  2023年   9篇
  2022年   10篇
  2021年   20篇
  2020年   23篇
  2019年   45篇
  2018年   50篇
  2017年   60篇
  2016年   66篇
  2015年   44篇
  2014年   58篇
  2013年   255篇
  2012年   40篇
  2011年   51篇
  2010年   36篇
  2009年   32篇
  2008年   36篇
  2007年   48篇
  2006年   25篇
  2005年   21篇
  2004年   24篇
  2003年   20篇
  2002年   17篇
  2001年   15篇
  2000年   12篇
  1999年   8篇
  1998年   3篇
  1997年   4篇
  1996年   9篇
  1995年   4篇
  1994年   4篇
  1993年   2篇
  1992年   3篇
  1991年   2篇
  1990年   3篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   5篇
  1985年   8篇
  1984年   6篇
  1983年   5篇
  1982年   3篇
  1981年   2篇
  1977年   1篇
  1976年   1篇
  1974年   2篇
  1973年   1篇
  1966年   1篇
  1926年   1篇
  1910年   1篇
排序方式: 共有1105条查询结果,搜索用时 125 毫秒
71.
Herein is described the fabrication and use of a plastic multilayer 3-channel microfluidic fixture. Multilayer devices were produced by laser machining of plastic polymethylmethacrylate and polyethyleneterapthalate laminates by ablation. The fixture consisted of an array of nine individually addressable gold or gold/ITO working electrodes, and a resistive platinum heating element. Laser machining of both the fluidic pathways in the plastic laminates, and the stencil masks used for thermal evaporation to form electrode regions on the plastic laminates, enabled rapid and inexpensive implementation of design changes. Electrochemiluminescence reactions in the fixture were achieved and monitored through ITO electrodes. Electroaddressable aryl diazonium chemistry was employed to selectively pattern gold electrodes for electrochemical multianalyte DNA detection from double stranded DNA (dsDNA) samples. Electrochemical detection of dsDNA was achieved by melting of dsDNA molecules in solution with the integrated heater, allowing detection of DNA sequences specific to breast and colorectal cancers with a non-specific binding control. Following detection, the array surface could be renewed via high temperature (95 °C) stripping using the integrated heating element. This versatile and simple method for prototyping devices shows potential for further development of highly integrated, multi-functional bioanalytical devices.  相似文献   
72.
The design and fabrication of a membrane-integrated microfluidic cell culture device (five layers,≤500 μm total thickness) developed for high resolution microscopy is reported here. The multi-layer device was constructed to enable membrane separated cell culture for tissue mimetic in vitro model applications and pharmacodynamic evaluation studies. The microdevice was developed via a unique combination of low profile fluidic interconnect design, substrate transfer methodology, and wet silane bonding. To demonstrate the unique high resolution imaging capability of this device, we used oil immersion microscopy to image stained nuclei and mitochondria in primary hepatocytes adhered to the incorporated membrane  相似文献   
73.
Many very young children attend early care and education programs, but current information about the quality of center-based care for toddlers is scarce. Using 2 observation instruments, the Infant/Toddler Environment Rating Scale–Revised (ITERS-R) and the Classroom Assessment Scoring System, Toddler Version (CLASS-Toddler), 93 child care classrooms for toddlers across the state of North Carolina, representing a range of quality, were assessed to determine overall quality, and associations between observed quality and teachers' ratings of child behavior problems and competence outcomes using the Brief Infant Toddler Social Emotional Assessment. Research Findings: Findings indicated that overall, toddler classrooms were rated as being of moderate quality. Associations between observed quality and teacher-reported child behavior problems and competence outcomes indicated that CLASS-Toddler ratings were positively associated with fewer behavior problems; specifically, children in classrooms with higher levels on the CLASS-Toddler domains of Emotional and Behavioral Support as well as Engaged Support for Learning were reported to have fewer behavior problems. Similarly, the ITERS-R subscales of Interaction and Listening and Talking were positively related to fewer reported behavior problems. Regression models showed that the CLASS-Toddler Emotional and Behavioral Support domain predicted differences in child behavior problems. Practice or Policy: Findings suggest the need for additional research related to very young children's experiences in center-based child care to examine associations between quality and child experiences and outcomes. Children's experiences over time need to be examined to understand how these early child care experiences are related to children's later school adjustment and performance. On a related note, professional development for teachers in toddler classrooms needs to be addressed in terms of preparing effective teachers for young children during the toddler developmental period.  相似文献   
74.
Schools are an important context for both basic and applied scientific research. Unlike the laboratory, however, the physical and social conditions of schools are not under the exclusive control of scientists. In this article, we liken collecting data in schools to putting on a theatrical production. We begin by describing the large cast of characters whose collaborative efforts make school‐based research possible. Next, we address the critics, including the university Institutional Review Board (IRB) and school administrators, whose feedback often improves the final study design. We then turn our attention to set building, stage directions, and rehearsals—key steps in the iterative process of refining study procedures. We end with a discussion of the day of data collection itself and activities that take place after the curtain drops. Throughout, we make recommendations based on our recent experience collecting data at several high schools.  相似文献   
75.
Abstract

Considerable research evidence supports the provision of explicit instruction for students at risk for reading difficulties; however, one of the most widely implemented approaches to early reading instruction is Guided Reading (GR; Fountas & Pinnel, 1996), which deemphasizes explicit instruction and practice of reading skills in favor of extended time reading text. This study evaluated the two approaches in the context of supplemental intervention for at-risk readers at the end of Grade 1. Students (n = 218) were randomly assigned to receive GR intervention, explicit intervention (EX), or typical school instruction (TSI). Both intervention groups performed significantly better than TSI on untimed word identification. Significant effects favored EX over TSI on phonemic decoding and one measure of comprehension. Outcomes for the intervention groups did not differ significantly from each other; however, an analysis of the added value of providing each intervention relative to expected growth with typical instruction indicated that EX is more likely to substantially accelerate student progress in phonemic decoding, text reading fluency, and reading comprehension than GR. Implications for selection of Tier 2 interventions within a response-to-intervention format are discussed.  相似文献   
76.
Over the past decade, repeated calls have been made to incorporate more active teaching and learning in undergraduate biology courses. The emphasis on inquiry-based teaching is especially important in laboratory courses, as these are the courses in which students are applying the process of science. To determine the current state of research on inquiry-based teaching in undergraduate biology laboratory courses, we reviewed the recent published literature on inquiry-based exercises. The majority of studies in our data set were in the subdisciplines of biochemistry, cell biology, developmental biology, genetics, and molecular biology. In addition, most exercises were guided inquiry, rather than open ended or research based. Almost 75% of the studies included assessment data, with two-thirds of these studies including multiple types of assessment data. However, few exercises were assessed in multiple courses or at multiple institutions. Furthermore, assessments were rarely based on published instruments. Although the results of the studies in our data set show a positive effect of inquiry-based teaching in biology laboratory courses on student learning gains, research that uses the same instrument across a range of courses and institutions is needed to determine whether these results can be generalized.  相似文献   
77.
78.
Experimental analysis of social stimuli has typically been restricted to the presence or absence of verbal attention. In the present study, an ABAB design was used to assess the influence of proximity as a social stimulus. Close and distant proximity of a familiar adult was systematically manipulated to evaluate the effect of proximity on the on‐task behavior of a 15‐year‐old male with autism. Baseline, experimental analysis, and intervention phases were conducted within a self‐contained classroom. Pronounced effects of distant educator proximity to the participant were evident during both the experimental analysis and intervention, with increased on‐task behavior occurring in the distant condition. Future recommendations for the investigation of proximity as a relevant social stimulus are forwarded. © 2005 Wiley Periodicals, Inc. Psychol Schs 42: 189–196, 2005.  相似文献   
79.
80.
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