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   116082篇
  免费   4000篇
  国内免费   2090篇
电工技术   2742篇
技术理论   2篇
综合类   4691篇
化学工业   16959篇
金属工艺   6787篇
机械仪表   5223篇
建筑科学   4650篇
矿业工程   1694篇
能源动力   1990篇
轻工业   6058篇
水利工程   1933篇
石油天然气   2123篇
武器工业   256篇
无线电   12865篇
一般工业技术   19821篇
冶金工业   3951篇
原子能技术   677篇
自动化技术   29750篇
  2024年   157篇
  2023年   594篇
  2022年   1193篇
  2021年   1642篇
  2020年   1265篇
  2019年   1025篇
  2018年   15377篇
  2017年   14372篇
  2016年   10951篇
  2015年   2089篇
  2014年   2103篇
  2013年   2337篇
  2012年   5465篇
  2011年   11843篇
  2010年   10400篇
  2009年   7587篇
  2008年   8712篇
  2007年   9524篇
  2006年   1763篇
  2005年   2425篇
  2004年   2069篇
  2003年   2089篇
  2002年   1639篇
  2001年   1034篇
  2000年   831篇
  1999年   725篇
  1998年   503篇
  1997年   364篇
  1996年   364篇
  1995年   286篇
  1994年   221篇
  1993年   176篇
  1992年   95篇
  1991年   99篇
  1990年   59篇
  1989年   61篇
  1988年   49篇
  1969年   24篇
  1968年   43篇
  1967年   33篇
  1966年   42篇
  1965年   44篇
  1963年   28篇
  1960年   30篇
  1959年   37篇
  1958年   37篇
  1957年   36篇
  1956年   34篇
  1955年   63篇
  1954年   68篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
2.
Mobile software applications have to cope with a particular environment that involves small size, limited resources, high autonomy requirements, competitive business models and many other challenges. To provide development guidelines that respond to these needs, several practices have been introduced; however, it is not clear how these guidelines may contribute to solve the issues present in the mobile domain. Furthermore, the rapid evolution of the mobile ecosystem challenges many of the premises upon which the proposed practices were designed. In this paper, we present a survey of the literature on software assurance practices for mobile applications, with the objective of describing them and assessing their contribution and success. We identified, organized and reviewed a body of research that spans in three levels: software development processes, software product assurance practices, and software implementation practices. By carrying out this literature survey, we reviewed the different approaches that researchers on Software Engineering have provided to address the needs that raise in the mobile software development arena. Moreover, we review the evolution of these practices, identifying how the constant changes and modernization of the mobile execution environment has impacted the methods proposed in the literature. Finally, we introduced discussion on the application of these practices in a real productive setting, opening an area for further research that may determine if practitioners have followed the proposed assurance paradigms.  相似文献   
3.
The purpose of present study was to develop and evaluate methods to assess stimulation responses of the lumbar extensors, as part of a longer‐term goal of detecting fatigue during prolonged sitting. Three stimulation frequencies (2, 5, and 8 Hz) were tested in separate stages, which include 3 stimulation trains and 4 sampling blocks. Repeated measures analyses of variance were used to determine whether any significant differences in mean stimulation responses occurred with respect to stimulation frequency, sampling block, and stimulation train. Reliability of measured stimulation responses was assessed within and between sampling blocks using intraclass correlation coefficients. Stimulation frequencies significantly affected the stimulation responses and time‐to‐potentiation differed between the 3 stimulation frequencies; it was highest for 2 Hz stimulation. All 3 stimulation frequencies resulted in excellent reliability within and between sampling blocks. Use of the current protocol at 2 Hz is recommended as appropriate to measure the lumbar extensors status during prolonged sitting.  相似文献   
4.
5.
6.
Variations of Incomplete Open Cubes is the major project by the twentieth-century conceptual artist Sol LeWitt. In this paper we interpret the enumerative component of the project as embeddings of graphs. This formulation permits use of an algorithm to check the completeness of the list of the structures produced by the artist. Our conclusion is that the artist found the correct number of structures (that is, 122), but that his list contains a mistake in the presentation of a pair of incomplete cubes, a discovery that appears not to have been noted before.  相似文献   
7.
Jia  Yuan  Wang  Yangli  Song  Rui  Li  Jiandong 《Multimedia Tools and Applications》2015,74(6):1777-1803
Multimedia Tools and Applications - In Wyner-Ziv (WZ) video coding, decoder side information (SI) takes a key role in a WZ video codec among other building blocks. In this paper, we review the...  相似文献   
8.
拆柱机由电动机匹配乳化液泵将电能转化为泵的液压能,带动液压马达回转作为拆装柱的动力。  相似文献   
9.
10.
基于图像增强方法,本文提出了一种使用亮度映射的图像去雾快速算法。此算法通过调整室外多雾场景图像的对比度,提高了雾中物体的辨识度。算法的复杂度低、处理延迟小,实时性高,利于FPGA的实现。实现时不需外存储器,延时为ns级,并提供了强度调节接口,以适应较广的应用环境。  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