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   2232篇
  免费   3篇
  国内免费   3篇
电工技术   15篇
化学工业   159篇
金属工艺   28篇
机械仪表   29篇
建筑科学   13篇
矿业工程   9篇
能源动力   5篇
轻工业   8篇
水利工程   11篇
石油天然气   30篇
武器工业   2篇
无线电   66篇
一般工业技术   179篇
冶金工业   1582篇
原子能技术   94篇
自动化技术   8篇
  2022年   9篇
  2019年   17篇
  2018年   21篇
  2017年   17篇
  2016年   16篇
  2014年   17篇
  2013年   24篇
  2012年   17篇
  2011年   20篇
  2010年   26篇
  2009年   14篇
  2008年   19篇
  2007年   18篇
  2006年   20篇
  2005年   9篇
  2004年   19篇
  2003年   24篇
  2002年   15篇
  2001年   15篇
  1999年   33篇
  1998年   472篇
  1997年   269篇
  1996年   191篇
  1995年   153篇
  1994年   91篇
  1993年   100篇
  1992年   25篇
  1991年   31篇
  1990年   20篇
  1989年   15篇
  1988年   19篇
  1987年   19篇
  1986年   13篇
  1985年   20篇
  1984年   11篇
  1983年   16篇
  1982年   14篇
  1981年   22篇
  1980年   33篇
  1979年   8篇
  1978年   20篇
  1977年   74篇
  1976年   113篇
  1975年   10篇
  1974年   9篇
  1973年   12篇
  1971年   7篇
  1965年   8篇
  1964年   6篇
  1963年   7篇
排序方式: 共有2238条查询结果,搜索用时 296 毫秒
1.
Journal of Communications Technology and Electronics - In recent years, there has been a rapid improvement in photonics products due to the use of multilayer heterostructures grown on the basis of...  相似文献   
2.
Strength of Materials - The paper addresses the investigation of high-strain rate compressive behavior of Al foams subjected to impact at the intermediate striking velocity ranged from 40 to...  相似文献   
3.
An instrument is proposed for continuously tracking the Sun and measuring its height by the use of a laser gyrometer as measuring converter. The accuracy in photoelectric sighting on the Sun is improved by greatly reducing the light fluxes to be compared by screening out the central part of the Sun's image in the focal plane. Translated from Izmeritel'naya Tekhnika, No. 3, pp. 7–9, March, 1994.  相似文献   
4.
We characterize the meander of re-entrant excitation in a model of a sheet of mammalian ventricular tissue, and its control by resonant drift under feedback driven stimulation. The Oxsoft equations for excitability in a guinea pig single ventricular cell were incorporated in a two dimensional reaction-diffusion system to model homogeneous, isotropic tissue with a plane wave conduction velocity of 0.35 m s-1. Re-entrant spiral wave solutions have a spatially extended transient motion (linear core) that settles down into rotation with an irregular period of 100-110 ms around an irregular, multi-lobed spiky core. In anisotropic tissue this would appear as a linear conduction block. The typical velocity of drift of the spiral wave induced by low amplitude resonant forcing is 0.4 cm s-1.  相似文献   
5.
The report deals with the development of procedures, evaluation of laser application and prevention of complications involved in intensive chemoradiation therapy of neoplasms of hemopoietic and lymphoid tissue in childhood. The clinical data on 548 patients, aged 2 months-15 years, with leukemia and solid tumor were evaluated. Laser application for treatment of different complications of chemoradiation therapy of pediatric leukemia proved a valuable innovation. It had a pronounced antiinflammatory and analgetic effect, promoted tissue regeneration processes and cut down the duration of complication treatment drastically.  相似文献   
6.
7.
8.
9.
Sustained world economic development trends characteristic with international trade annual growth rate of 7–8% along with considerable dynamics in the interregional goods circulation sphere on one hand and vast territory of Russia combined with a relatively developed railway network on the other hand provide a unique chance for this country to arrange land transportation routes alternative and competitive in comparison with existing marine routes. Construction of rail tunnels seems to be most efficient means for transportation corridors to cross-wide water areas like Nevelsky Strait (10.5 km) between the mainland and the Sakhalin Island in Russia, Bering Strait (92 km) between Chukotka Peninsula (Russia) and Alaska (USA). The tunnels construction conditions, structures and technologies planned to be used are considered in the paper.  相似文献   
10.
Gonadotropin-releasing hormone (GnRH) molecular variants in the brain and pituitary gland of pejerrey, Odontesthes bonariensis (Atheriniformes), were characterized by gradient reverse phase high performance liquid chromatography (RP-HPLC). Eluted fractions were tested in radioimmunoassays with different antisera. The results show that the brain extract contains three forms of GnRH: one is immunologically and chromatographically similar to cIIGnRH (chicken II), and another is similar to sGnRH (salmon). A third GnRH appears to be chromatographic and immunologically different from the nine other known forms of the vertebrate hormone. This is the only variant present in the pituitary gland.  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