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   2957篇
  免费   15篇
  国内免费   2篇
电工技术   18篇
化学工业   244篇
金属工艺   50篇
机械仪表   36篇
建筑科学   126篇
矿业工程   7篇
能源动力   66篇
轻工业   203篇
水利工程   24篇
石油天然气   11篇
无线电   173篇
一般工业技术   376篇
冶金工业   1397篇
原子能技术   13篇
自动化技术   230篇
  2022年   15篇
  2021年   15篇
  2019年   21篇
  2017年   22篇
  2016年   15篇
  2015年   24篇
  2014年   25篇
  2013年   115篇
  2012年   55篇
  2011年   85篇
  2010年   71篇
  2009年   59篇
  2008年   71篇
  2007年   77篇
  2006年   69篇
  2005年   71篇
  2004年   65篇
  2003年   56篇
  2002年   42篇
  2001年   49篇
  2000年   46篇
  1999年   70篇
  1998年   398篇
  1997年   230篇
  1996年   152篇
  1995年   114篇
  1994年   110篇
  1993年   93篇
  1992年   40篇
  1991年   32篇
  1990年   30篇
  1989年   31篇
  1988年   28篇
  1987年   31篇
  1986年   24篇
  1985年   28篇
  1984年   21篇
  1983年   15篇
  1982年   30篇
  1981年   26篇
  1980年   20篇
  1979年   24篇
  1978年   25篇
  1977年   58篇
  1976年   106篇
  1975年   17篇
  1974年   13篇
  1973年   19篇
  1972年   14篇
  1968年   13篇
排序方式: 共有2974条查询结果,搜索用时 0 毫秒
1.
Many current implementations of protocols such as the Transmission Control Protocol/Internet Protocol (TCP/IP) are inefficient because data are often accessed more frequently than necessary. Three techniques that reduce the need for memory bandwidth are proposed. The techniques are copy-on-write, page remapping, and single-copy. Afterburner, a network-independent card that provides the services that are necessary for a single-copy protocol stack, is described. The card has 1 MByte of local buffers and provides a simple interface to a variety of network link adapters, including HIPPI and asynchronous transfer mode (ATM). Afterburner can support transfers to and from the link adapter card at rates up to 1 Gbit/s. An implementation of TCP/IP that uses the features provided by Afterburner to reduce the movement of data to a single copy is discussed. Measurements of the end-to-end performance of Afterburner and the single-copy implementation of TCP/IP are presented  相似文献   
2.
Elasticity is discussed as an aspect of viscoelasticity, which is described by the tube model. The effects of both crosslinks and entanglements contribute to this model and a discussion of how these effects can be quantified is given. At high enough concentration, entanglements ensure the existence of elastic effects even without crosslinks, and a theory is presented on how this dynamical phase change comes about.  相似文献   
3.
The authors highlight several possible ways in which the construction industry could lower present emissions of the greenhouse gas, carbon dioxide. It is an excellent discussion document and is recommended reading.  相似文献   
4.
5.
The present study was designed to investigate the type and extent of degeneration occurring in the human central auditory system subsequent to profound hearing loss. The authors have examined the size of one population of neurons in the ventral cochlear nucleus in seven subjects with profound hearing loss (audiometric responses poorer than 90-100 dB HL). Six normal subjects, ages 35-78, were used as controls. Cell size in the hearing-impaired subjects ranged from normal to reduced by more than 50 percent. Two factors appear to contribute to the variability in cell size reduction. The correlation coefficient (Spearman rs) of cell size with duration of profound deafness was -0.48, indicating a moderate tendency for neurons to become smaller with longer periods of deafness. The correlation coefficient of cell size with number of surviving cochlear ganglion cells was 0.73, indicating a stronger tendency for neurons to be larger with greater eighth nerve innervation of the cochlear nucleus. Two cases of Scheibe degeneration showed the most severe degenerative change in the central auditory system.  相似文献   
6.
7.
8.
With IPv6 transitioning still in a relative state of flux, the need has emerged for methods to control this crucial aspect of IPv6 deployments. This article makes the case for transitioning architectures as a realistic solution to this issue, specifically within large-scale networks. The Site Transitioning Architecture (STA) supports the deployment, operation, and management of IPv6 transitioning mechanisms. The authors provide an overview of the STA's design and operation, noting that its flexible, simple, and secure architecture is suitable for the duration of the IPv6 deployment process, regardless of the underlying network environment.  相似文献   
9.
Considers a sliding-mode controller which requires only output information and is static in nature. The novelty of the approach is in the rationale and method used to synthesize the linear control component which involves a linear matrix inequality optimization. The so-called reachability condition used in sliding-mode controller analysis is not required to be satisfied globally. Instead, sliding is only expected to take place within a subset of the state-space referred to as the sliding patch  相似文献   
10.
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