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   2173篇
  免费   16篇
  国内免费   27篇
电工技术   12篇
综合类   37篇
化学工业   40篇
金属工艺   41篇
机械仪表   17篇
建筑科学   25篇
矿业工程   3篇
能源动力   7篇
轻工业   5篇
水利工程   1篇
石油天然气   70篇
武器工业   1篇
无线电   330篇
一般工业技术   66篇
冶金工业   1524篇
原子能技术   2篇
自动化技术   35篇
  2024年   9篇
  2021年   4篇
  2019年   4篇
  2017年   3篇
  2015年   3篇
  2013年   14篇
  2012年   5篇
  2011年   12篇
  2010年   15篇
  2009年   6篇
  2008年   8篇
  2007年   7篇
  2006年   4篇
  2005年   7篇
  2004年   30篇
  2003年   31篇
  2002年   42篇
  2001年   26篇
  2000年   27篇
  1999年   71篇
  1998年   592篇
  1997年   344篇
  1996年   175篇
  1995年   115篇
  1994年   81篇
  1993年   131篇
  1992年   35篇
  1991年   47篇
  1990年   56篇
  1989年   48篇
  1988年   28篇
  1987年   28篇
  1986年   22篇
  1985年   19篇
  1984年   8篇
  1983年   6篇
  1982年   8篇
  1981年   5篇
  1980年   11篇
  1979年   4篇
  1978年   7篇
  1977年   25篇
  1976年   55篇
  1971年   4篇
  1969年   2篇
  1965年   5篇
  1964年   2篇
  1963年   5篇
  1961年   2篇
  1958年   3篇
排序方式: 共有2216条查询结果,搜索用时 15 毫秒
61.
Percutaneous balloon pericardiotomy is effective and less invasive for the treatment of recurrent pericardial effusion. This study suggests that the double-balloon method with 1 longer and 1 shorter balloon is the procedure of choice for percutaneous balloon pericardiotomy.  相似文献   
62.
Effects were studied of vincamin and tanakan in 68 patients with stage I, II and III discirculatory encephalopathy (as per WHO classification 1981). In 52% of the patients atherosclerosis of brain vessels was associated with arterial hypertension (group I), in 48 per cent venous discirculatory encephalopathy was diagnosable against the background of arterial hypertension (group IIA-20%) and arterial hypotension (group IIB-26%). Both tanakan and vincamin were found to be effective in group I patients; however, in stage III condition their effectiveness was no better than 42 and 15% respectively, which fact might be due to organic changes in the vascular wall. Tanakan appeared to be more beneficial in group II patients since venous dystonia is considered to be the main pathogenetic link in this context, and tanakan is known to improve the venous outflow from the cranial cavity. Almost in one-third of group IIB patients vincamin worsened general health status, especially so in stage III discirculatory encephalopathy, which fact may be related to peculiar effect of the drug on the arterial link of brain blood supply.  相似文献   
63.
廖蔚  聂雪娥 《电讯技术》1993,33(1):67-74
本文介绍了一种分布式油库自动化控制,管理微机系统YKGX-1。重点介绍了其功能、组成、原理及特点。经实际运行证明,YKGX-1系统实现了油库收、发、存、管理一体化,系统自动化程度高,发油精度优于3‰。  相似文献   
64.
65.
Endocrine disorders in critically ill infants and children can be the manifestation of an existing but previously unrecognized condition, or hormonal derangements precipitated by deleterious effects on endocrine function of a critical illness or its prescribed therapy. To achieve successful resolution of these crises, a general understanding of various endocrine dysfunctions, clinical symptomatology, diagnosis, and medical and nursing management is essential.  相似文献   
66.
67.
95W-Ni-Fe 合金工艺缺陷的 SAM 和 XPS 分析   总被引:3,自引:0,他引:3  
藉助扫描俄歇探针、X射线光电子谱等分析了95W-Ni-Fe合金碳污染和氧化的本质。发现,碳污染试样中碳的化学状态主要为石墨,少量为铁或镍的有机化合物,这些物质的界面富集使材料脆化。钨合金氧化后,氧大量富集于钨/粘结相界面,使沿着该界面的断裂更容易发生。  相似文献   
68.
Protein phosphorylation plays a central role in many biological and biomedical phenomena. In this review, while a brief overview of the occurrence and function of protein phosphorylation is given, the primary focus is on studies related to the detection and analysis of phosphorylation both in vivo and in vitro. We focus on phosphorylation of serine, threonine and tyrosine, the most commonly phosphorylated amino acids in eukaryotes. Technologies such as radiolabelling, antibody recognition, chromatographic methods (HPLC, TLC), electrophoresis, Edman sequencing and mass spectrometry are reviewed. We consider the speed, simplicity and sensitivity of tools for detection and identification of protein phosphorylation, as well as quantitation and site characterisation. The limitations of currently available methods are summarised.  相似文献   
69.
We describe methods for the production of fluorescence in situ hybridization (FISH) probes and the utilization of these probes for the detection of complementary DNA sequences with accuracy and sensitivity for application in both basic research and clinical diagnosis. Due to the frequent use of FISH in many laboratories, it is important to apply the most convenient and reproducible approach. This review describes some of the most recent techniques, and includes versatile, effective and simple methods of probe production and fluorescence in situ hybridization. We also describe methods for the production of region-specific and chromosome-specific DNA probes and hybridization techniques for the visualization of these probes.  相似文献   
70.
The fusion of intracellular transport vesicles with their target membranes requires the assembly of SNARE proteins anchored in the apposed membranes. Here we use recombinant cytoplasmic domains of the yeast SNAREs involved in Golgi to plasma membrane trafficking to examine this assembly process in vitro. Binary complexes form between the target membrane SNAREs Sso1p and Sec9p; these binary complexes can subsequently bind to the vesicle SNARE Snc2p to form ternary complexes. Binary and ternary complex assembly are accompanied by large increases in alpha-helical structure, indicating that folding and complex formation are linked. Surprisingly, we find that binary complex formation is extremely slow, with a second-order rate constant of approximately 3 M(-1) s(-1). An N-terminal regulatory domain of Sso1p accounts for slow assembly, since in its absence complexes assemble 2,000-fold more rapidly. Once binary complexes form, ternary complex formation is rapid and is not affected by the presence of the regulatory domain. Our results imply that proteins that accelerate SNARE assembly in vivo act by relieving inhibition by this regulatory domain.  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