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   4914篇
  免费   334篇
  国内免费   149篇
电工技术   111篇
综合类   378篇
化学工业   1480篇
金属工艺   39篇
机械仪表   300篇
建筑科学   311篇
矿业工程   190篇
能源动力   111篇
轻工业   513篇
水利工程   41篇
石油天然气   326篇
武器工业   30篇
无线电   60篇
一般工业技术   379篇
冶金工业   393篇
原子能技术   17篇
自动化技术   718篇
  2024年   9篇
  2023年   38篇
  2022年   80篇
  2021年   104篇
  2020年   111篇
  2019年   73篇
  2018年   87篇
  2017年   91篇
  2016年   140篇
  2015年   124篇
  2014年   233篇
  2013年   255篇
  2012年   316篇
  2011年   322篇
  2010年   285篇
  2009年   314篇
  2008年   257篇
  2007年   389篇
  2006年   339篇
  2005年   290篇
  2004年   266篇
  2003年   262篇
  2002年   192篇
  2001年   175篇
  2000年   132篇
  1999年   102篇
  1998年   70篇
  1997年   61篇
  1996年   48篇
  1995年   53篇
  1994年   24篇
  1993年   27篇
  1992年   25篇
  1991年   17篇
  1990年   10篇
  1989年   10篇
  1988年   6篇
  1987年   7篇
  1986年   3篇
  1985年   6篇
  1984年   6篇
  1982年   4篇
  1966年   3篇
  1964年   7篇
  1963年   2篇
  1961年   3篇
  1959年   3篇
  1957年   2篇
  1956年   3篇
  1955年   2篇
排序方式: 共有5397条查询结果,搜索用时 15 毫秒
1.
Numerous conceptual difficulties and misconceptions have been reported in the science and chemistry education literature about electrochemistry concepts such as electrolytes, redox equations, and about electrochemical (galvanic and electrolytic) cells. Other studies have considered teaching approaches aimed at improving learning and at overcoming misconceptions. This paper reviews these studies and considers strategies and approaches for the effective teaching of electrochemistry. Then, the review focuses on problem solving in equilibrium electrochemistry, especially problems involving the Nernst equation. The main findings of four studies with Greek university chemistry students, dealing with: (i) algorithmic problem‐solving ability; (ii) practice on problem solving; (iii) the effect of the format of a problem; and (iv) the construction and evaluation of a website devoted to electrochemistry problem solving, are reported.  相似文献   
2.
Intended learning outcomes (ILOs) indicate what learners will be able to achieve after they are taught. Traditionally, ILOs are expressed as plain text or unstructured documents. What if all ILOs of a specific course of study can be conceptualized through a structured diagrammatic technique? It was hypothesized that learners can benefit from this conceptualization in learning, especially in self‐regulated learning. The aim of this study was to investigate whether the ILOs represented in unstructured or structured formats can facilitate learners to identify learning paths. The results revealed that the mean ratings of all learning paths were statistically significantly higher with structured ILOs.  相似文献   
3.
4.
When solving a mathematical problem, students who do not have sufficient conceptual understanding may perform poorly and exhibit misconceptions. This study was aimed to examine students' conceptual understanding and significant misconceptions when solving number sense‐related problems. An online three‐tier diagnostic test was administered to 125 fifth‐grade students with varied socio‐economic backgrounds in Hong Kong. Only 14.40% of the students exhibited high performance with high confidence, indicating that these students had a profound conceptual understanding of number sense. In addition, the majority of the students (66.40%) did not demonstrate number sense; these students exhibited several significant misconceptions and could solve the questions only by using a rule‐based method or guessing. Accordingly, most students performed unsatisfactorily on number sense‐related problems. This study is imperative in identifying early predictors and provides information for further compatible interventions in the teaching and learning of number sense in Hong Kong in particular and worldwide in general.  相似文献   
5.
6.
研究了以集合论为基础的调度优化模型。给出了该离散型优化问题的求解算法。根据优化结果,在G2实时智能平台上开发了包含监视子系统和调度子系统的调度支持系统。在中国石化股份有限公司长岭分公司的试用结果表明,该调度系统可以提高炼油厂的生产效率,从而提高炼油厂的经济效益。  相似文献   
7.
2-D SHAPE BLENDING OF NURBS CURVE SHAPES   总被引:2,自引:0,他引:2  
2-DSHAPEBLENDINGOFNURBSCURVESHAPESJinXiaogang;BaoHujun;PengQunsheng2-DSHAPEBLENDINGOFNURBSCURVESHAPES¥JinXiaogang;BaoHujun;Pe...  相似文献   
8.
The authors investigated the impact of semantic knowledge on visual object analysis by assessing the performance of patients with semantic dementia on a different-views object matching test and on 2 object decision tests differing, for example, in whether the nonreal items were nonsense objects or chimeras of 2 real objects. On average, the patients scored normally on both the object matching and the object decision test including nonsense objects but were impaired on the object decision test including chimeras; this latter was also the only visual object test that correlated significantly with degree of semantic impairment. These findings demonstrate that object decision is not a single task or ability and that it is not necessarily independent of conceptual knowledge. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
9.
Advances in research on disability and rehabilitation are essential to creating equal opportunity, economic self-sufficiency, and full participation for persons with disabilities. Historically, such initiatives have focused on separate and specific areas, including neuroscience, molecular biology and genetics, gerontology, engineering and physical sciences, and social and behavioral sciences. Research on persons with disabilities should examine the broader context and trends of society that affect the total environment of persons with disabilities. This article examines the various disability paradigms across time, assessing the relative contribution of the socioecological perspective in guiding research designed to improve the lives of persons with disabilities. The authors recommend new research directions that include a focus on life span issues, biomedicine, biotechnology, the efficacy and effectiveness of current interventions, an emphasis on consumer-driven investigations within a socioecological perspective of disability, and the implications for research and practice. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
10.
本文阐述了不锈钢冶炼的关键技术,为生产准备提供帮助。  相似文献   
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