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   1760篇
  免费   107篇
  国内免费   98篇
化学   618篇
晶体学   13篇
力学   84篇
综合类   44篇
数学   917篇
物理学   289篇
  2023年   14篇
  2022年   61篇
  2021年   45篇
  2020年   56篇
  2019年   49篇
  2018年   38篇
  2017年   62篇
  2016年   61篇
  2015年   48篇
  2014年   75篇
  2013年   115篇
  2012年   87篇
  2011年   104篇
  2010年   101篇
  2009年   111篇
  2008年   124篇
  2007年   151篇
  2006年   172篇
  2005年   122篇
  2004年   86篇
  2003年   46篇
  2002年   30篇
  2001年   28篇
  2000年   26篇
  1999年   32篇
  1998年   12篇
  1997年   13篇
  1996年   13篇
  1995年   12篇
  1994年   7篇
  1993年   7篇
  1992年   3篇
  1991年   11篇
  1990年   2篇
  1989年   4篇
  1988年   9篇
  1987年   1篇
  1986年   6篇
  1985年   2篇
  1984年   6篇
  1982年   2篇
  1981年   2篇
  1978年   1篇
  1977年   4篇
  1975年   1篇
  1974年   2篇
  1973年   1篇
排序方式: 共有1965条查询结果,搜索用时 281 毫秒
271.
大学生科研训练计划是培养创新型人才的重要措施。以创新教育理念为出发点,以光学工程学科的专业基础课程应用光学为基础,从课程与周边学科的联系中,从教师的高水平科研项目以及地方企业的实际需求中提取原料和课题供给学生从事研究。仅就近两年内先后指导的11项共计40余名学生的SRTP项目为例,指导学生撰写论文和申请专利,有效地开阔了学生的视野,培养了学生的研究能力、创新思维与工程素质,提高了课程的教学质量,对其它专业基础课程建设具有借鉴意义。  相似文献   
272.
提出了利用带预冷的林德制冷系统获得了150K温区的制冷方案。建立了实验装置,进行了不同配比的三元混合工质(R23/R14/Ar)的制冷循环的性能实验。实验结果表明:三元混合工质(R23/R14/Ar)的最佳配比为0.46:0.39:0.15,在无热负荷时,制冷温度为150K时,降温时间为85m in。  相似文献   
273.
The article presents a study of face-to-face verbal communication when pupils work with geometry in pairs and share a stand-alone computer with Geoboard software. The work sessions of pairs of 9th grade pupils are video recorded, and a screen recorder is used to capture their computer activity. The study focuses on identifying and characterizing good communication practices that enhance mathematics learning through joint research reflections between the pupils, the teacher, and the researcher. The major finding concerns how two of the pupils have diverging perspectives on how to communicate mathematics, yet they manage to have productive collaboration. The differences generate collaborative challenges for the pupils and an opportunity to discuss how pupils’ communication qualities can prove important in fruitfully managing such challenges.  相似文献   
274.
It has been two months since a boom of online education triggered by the epidemic in China. At present, we are keeping focus on how to optimize our online class. In the case of chemistry laboratory courses, there's not much that can be done to experimental operations through online teaching. While for the traditional teaching procedure, there is still room for improvement in terms of integrating research to teaching, interactivity, etc. This paper will present some design strategies for improving teaching the organic chemistry laboratory online. To be specific, it describes how teaching materials like the lesson plan and virtual lab were coordinated into the online teaching. And we will also discuss the holistic approach to a better outcome for students' active learning and integration research into teaching by redesigning multiple phases, such as the pre-laboratory preparation, live online class, experimental operations.  相似文献   
275.
Self-explicated approaches are popular preference measurement approaches for products with many attributes. This article classifies previous self-explicated approaches according to their evaluation types, i.e. trade-off- versus non-trade-off-based, and outlines their advantages and disadvantages. In addition, it proposes a new method, the presorted adaptive self-explicated approach that is based on Netzer and Srinivasan’s (2011) adaptive self-explicated approach and that combines trade-off- and non-trade-off-based evaluation types. Two empirical studies compare this new method with the most popular existing self-explicated approaches, including the adaptive self-explicated approach and paired comparison preference measurement. The new method overcomes the insufficient discrimination between importance weights, as usually found in non-trade-off-based evaluation types; discourages respondents’ simplification strategies, as are frequently encountered in trade-off evaluation types; is easy to implement; and yields high predictive validity compared with other popular self-explicated approaches.  相似文献   
276.
针对仪器分析课程的特点,将"教研结合"的教学模式用于仪器分析理论教学中。通过对科研实例的深入解析,将涉及的相关教材知识穿插讲解。同时在仪器分析实验教学中采用"翻转课堂"的教学模式,即以"学生讲为主、教师讲为辅"的方式改变传统实验教学的弊端。从理论与实验两方面对仪器分析课程教学模式进行改革。  相似文献   
277.
阐述了高水平学术型硕士研究生培养与本科科研体验衔接的基本情况,以化学专业为例,就学术型硕士培养与本科创新性科研实践的衔接模式进行了详细的剖析,指出2者的衔接有助于高层次、高科研水平与高创新能力的硕士研究生培养。  相似文献   
278.
仪器分析实验在大学化学实验教学中占有非常重要的地位,结合吉林大学化学学院仪器分析实验“产、学、研、用”一体化教学模式,从实验教学内容的改革与探索和实验教学平台的建设与实践2个方面,围绕教学仪器的研制与开发、教学方法与课程设计、育人模式与运行机制等内容进行了分析和论述。  相似文献   
279.
The analysis of a historical document of a registry office from nineteenth century through Raman spectroscopy was performed by comparing with an ensemble of standard samples synthesized from cotton and linen raps. Structural parameters of the fibers of the cellulose, such as crystallinity, chain length, intermolecular interactions and packing, were obtained by the measurement of intensity ratios of some marker features. The results suggested the historical document has a cellulosic support originated from cotton, probably produced without basic pH treatment of the raw material.  相似文献   
280.
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