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   37250篇
  免费   2673篇
  国内免费   1125篇
电工技术   766篇
技术理论   7篇
综合类   8159篇
化学工业   1190篇
金属工艺   543篇
机械仪表   1099篇
建筑科学   13471篇
矿业工程   298篇
能源动力   155篇
轻工业   322篇
水利工程   398篇
石油天然气   258篇
武器工业   149篇
无线电   2878篇
一般工业技术   1035篇
冶金工业   1164篇
原子能技术   40篇
自动化技术   9116篇
  2024年   119篇
  2023年   623篇
  2022年   911篇
  2021年   1163篇
  2020年   1152篇
  2019年   823篇
  2018年   564篇
  2017年   532篇
  2016年   643篇
  2015年   962篇
  2014年   2706篇
  2013年   1972篇
  2012年   2501篇
  2011年   2866篇
  2010年   2655篇
  2009年   2765篇
  2008年   2672篇
  2007年   2680篇
  2006年   2377篇
  2005年   1991篇
  2004年   1701篇
  2003年   1622篇
  2002年   1263篇
  2001年   855篇
  2000年   761篇
  1999年   524篇
  1998年   286篇
  1997年   195篇
  1996年   137篇
  1995年   145篇
  1994年   109篇
  1993年   76篇
  1992年   86篇
  1991年   73篇
  1990年   56篇
  1989年   50篇
  1988年   73篇
  1987年   44篇
  1986年   30篇
  1985年   37篇
  1984年   39篇
  1983年   17篇
  1982年   20篇
  1981年   9篇
  1979年   10篇
  1964年   9篇
  1958年   9篇
  1957年   19篇
  1955年   20篇
  1954年   11篇
排序方式: 共有10000条查询结果,搜索用时 171 毫秒
31.
32.
Abstract This article presents a study of a large scale incorporation of one data acquisitionsystem into physics teaching in Israel. By 1994 about 30% of the schools throughout the country used the V-scope, a 3-D multibody motion tracing system, in their lab programme. The views and reactions of post-training teachers, experienced teachers and students on various aspects of using the system are described, analysed and compared.  相似文献   
33.
电工电子系列课程的改革实践与整合优化   总被引:14,自引:7,他引:7  
介绍了东南大学电工电子系列课程的整体结构,阐述了下一步课程整合的方案并指出了课程改革中应注意的一些问题。  相似文献   
34.
The cost of maintaining a software system over a long period of time far exceeds its initial development cost. Much of the maintenance cost is attributed to the time required by new developers to understand legacy systems. High-level structural information helps maintainers navigate through the numerous low-level components and relations present in the source code. Modularization tools can be used to produce subsystem decompositions from the source code but do not typically produce high-level architectural relations between the newly found subsystems. Controlling subsystem interactions is one important way in which the overall complexity of software maintenance can be reduced.We have developed a tool, called ARIS (Architecture Relation Inference System), that enables software engineers to define rules and relations for regulating subsystem interactions. These rules and relations are called Interconnection Styles and are definedusing a visual notation. The style definition is used by our tool to infer subsystem-level relations in designs being reverse engineered from source code.In this paper we describe our tool and its underlying techniques and algorithms. Using a case study, we describe how ARIS is used to reverse engineer high-level structural information from a real application.  相似文献   
35.
The requirements on an object-oriented DBMS for management of information in a large, complex enterprise are presented. These requirements aid in the achievement of an environment characterized by data sharing, open architectures, application and data portability, and assurance of data integrity. They were defined from the point of view of a user of the DBMS; therefore they describe the expected functionality of the DBMS and do not specify the method of implementation to achieve this functionality. They encompass requirements on the data model, query and data manipulation languages, the system architecure, interfaces to the system, change management, and transaction management.  相似文献   
36.
How can psychologists and graduate students become more affirmative of lesbian, gay, bisexual, and transgender (LGBT) issues? Safe Zone is a diversity-training program to increase sensitivity toward, knowledge of, and advocacy for LGBT populations and issues that affect them. In this exploratory study, the implementation of Safe Zone is described within a school of professional psychology; its effectiveness was assessed by self-reported behavioral and attitudinal changes and from participant evaluations. Results were encouraging with regard to the goals of Safe Zone and its adaptation to institutions interested in improving relations with the LGBT community, but additional empirical studies are needed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
37.
Corner detection is a low-level feature detection operator that is of great use in image processing applications, for example, optical flow and structure from motion by image correspondence. The detection of corners is a computationally intensive operation. Past implementations of corner detection techniques have been restricted to software. In this paper we propose an efficient very large-scale integration (VLSI) architecture for detection of corners in images. The corner detection technique is based on the half-edge concept and the first directional derivative of Gaussian. Apart from the location of the corner points, the algorithm also computes the corner orientation and the corner angle and outputs the edge map of the image. The symmetrical properties of the masks are utilized to reduce the number of convolutions effectively, from eight to two. Therefore, the number of multiplications required per pixel is reduced from 1800 to 392. Thus, the proposed architecture yields a speed-up factor of 4.6 over conventional convolution architectures. The architecture uses the principles of pipelining and parallelism and can be implemented in VLSI.  相似文献   
38.
李治镇 《华中建筑》2005,23(B07):117-118
通过对汉口西商跑马场的调查,说明它移植武汉的经过和历程,以及它在建筑设计方面的一些特点。  相似文献   
39.
试论当代大学生IT素质的培养   总被引:1,自引:0,他引:1  
从IT素质的涵义出发,论述了IT素质的涵盖内容、培养大学生IT素质的重要性以及IT素质的本质与特点.对高校树立人才培养新理念、培养优秀IT人才提出了有关建议及应对措施。  相似文献   
40.
通过对高等教育伦理道德的探析,解读我国高等教育面临的道德困惑,以适应社会的发展。  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