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   1267篇
  免费   12篇
教育   887篇
科学研究   88篇
各国文化   13篇
体育   164篇
综合类   2篇
文化理论   5篇
信息传播   120篇
  2023年   3篇
  2022年   5篇
  2021年   23篇
  2020年   20篇
  2019年   41篇
  2018年   48篇
  2017年   43篇
  2016年   60篇
  2015年   30篇
  2014年   42篇
  2013年   318篇
  2012年   33篇
  2011年   38篇
  2010年   24篇
  2009年   36篇
  2008年   39篇
  2007年   38篇
  2006年   36篇
  2005年   34篇
  2004年   27篇
  2003年   27篇
  2002年   17篇
  2001年   18篇
  2000年   24篇
  1999年   20篇
  1998年   16篇
  1997年   13篇
  1996年   15篇
  1995年   17篇
  1994年   12篇
  1993年   8篇
  1992年   14篇
  1991年   11篇
  1990年   12篇
  1989年   12篇
  1988年   9篇
  1987年   3篇
  1986年   7篇
  1985年   8篇
  1984年   11篇
  1983年   7篇
  1982年   5篇
  1981年   10篇
  1980年   6篇
  1979年   4篇
  1978年   4篇
  1977年   7篇
  1976年   5篇
  1971年   3篇
  1828年   3篇
排序方式: 共有1279条查询结果,搜索用时 0 毫秒
81.
身体     
Mike 《阅读》2011,(11):42
  相似文献   
82.
While much prior research has focused upon how the Technology Transfer Offices (TTOs) and other contextual characteristics shape the level of university spinoffs (USO), there is little research on entrepreneurial potential among individual academics, and to the best of our knowledge, no comparative studies with other types of spinoffs exist to date. In this paper we focus on an important but neglected aspect of knowledge transfer from academic research involving the indirect flow to entrepreneurship by individuals with a university education background who become involved in new venture creation by means of corporate spinoffs (CSO) after gaining industrial experience, rather than leaving university employment to found a new venture as an academic spinoff. We argue that the commercial knowledge gained by industry experience is potentially more valuable for entrepreneurial performance compared to the academic knowledge gained by additional research experience at a university. This leads us to posit that the average performance of CSOs will be higher than comparable USOs, but the gains from founder‘s prior experiences will be relatively higher among USOs whose founders lack the corporate context. We investigate these propositions in a comparative study tracking the complete population of USOs and CSOs among the Swedish knowledge-intensive sectors between 1994 and 2002.  相似文献   
83.
84.
85.
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   
86.
In this study, carbon fiber electrodes were incorporated within a hollow microneedle array, which was fabricated using a digital micromirror device-based stereolithography instrument. Cell proliferation on the acrylate-based polymer used in microneedle fabrication was examined with human dermal fibroblasts and neonatal human epidermal keratinocytes. Studies involving full-thickness cadaveric porcine skin and trypan blue dye demonstrated that the hollow microneedles remained intact after puncturing the outermost layer of cadaveric porcine skin. The carbon fibers underwent chemical modification in order to enable detection of hydrogen peroxide and ascorbic acid; electrochemical measurements were demonstrated using integrated electrode-hollow microneedle devices.  相似文献   
87.
IntroductionIt is often quoted that 70% of clinical decisions are based on laboratory results, but the evidence to substantiate this claim is lacking. Since clinical guidelines aim to document best-practice decision making for specific disease conditions, inclusion of any laboratory test means that the best available evidence is recommending clinicians use it. Cardiovascular disease (CVD) is the world’s most common cause of mortality, so this study reviewed all CVD guidelines published by five national/international authorities to determine what proportion of them recommended laboratory testing.Materials and methodsFive leading CVD guidelines were examined, namely the European Society of Cardiology (ESC), the UK National Institute for Health and Clinical Excellence (NICE), the American College of Cardiology (ACC), the Australian Heart Foundation (AHF) and the Cardiac Society of Australia and New Zealand (CSANZ).ResultsA total of 101 guidelines were reviewed. Of the 33 individual ESC guidelines relating to CVD, 24/33 made a direct reference to the use of clinical laboratory tests in either diagnosis or follow-up treatment. The same applied to 15/20 of NICE guidelines, 24/32 from the ACC and 15/16 from the AHF/CSANZ. Renal function and blood count testing were the most recommended (39 and 26 times), with lipid, troponin and natriuretic peptide measurement advocated 25, 19 and 19 times respectively.ConclusionsThis study has shown that laboratory testing is advocated by between 73% and 94% of individual CVD guideline recommendations from five national/international authorities. This provides an index to assess the potential value of laboratory medicine to healthcare.  相似文献   
88.
Research Findings: There is growing acknowledgment of the need for parenting interventions to address early-onset behavior and emotional concerns. Favorable child outcomes have been linked to parents’ responsiveness and positive expressiveness. Given the theoretical and empirical link between perceptions and actual behavior, Head Start mothers (n = 114) participated in an investigation to examine factors that may be associated with level of self-reported maternal expressiveness. Participants completed the Self-Expressiveness in the Family Questionnaire (Halberstadt, Cassidy, Stifter, Parke, & Fox, 1995). Analysis suggested that self-reported high negative expressiveness was linked with raising a preschooler with perceived internalizing and externalizing behaviors, high parenting stress, and obtaining a post–high school degree. A perceived view of being low in positive expressiveness, in contrast, correlated with different variables, including raising a preschooler with a diagnosed delay, not having any child receive specialized services, raising only 1 child, dropping out of high school, and not receiving behavior advice from Head Start staff. Practice or Policy: Implications for examining self-reported low positive and high negative expressiveness as separate constructs with possibly different intervention pathways are discussed.  相似文献   
89.
90.
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