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   2382篇
  免费   1篇
  国内免费   1篇
电工技术   15篇
化学工业   118篇
金属工艺   48篇
机械仪表   46篇
建筑科学   6篇
矿业工程   12篇
能源动力   2篇
轻工业   7篇
水利工程   37篇
石油天然气   59篇
无线电   82篇
一般工业技术   183篇
冶金工业   1634篇
原子能技术   91篇
自动化技术   44篇
  2021年   9篇
  2019年   9篇
  2018年   19篇
  2017年   20篇
  2016年   26篇
  2014年   25篇
  2013年   31篇
  2012年   24篇
  2011年   27篇
  2010年   37篇
  2009年   30篇
  2008年   21篇
  2007年   33篇
  2006年   21篇
  2005年   21篇
  2004年   22篇
  2003年   13篇
  2002年   19篇
  2001年   9篇
  2000年   14篇
  1999年   32篇
  1998年   413篇
  1997年   264篇
  1996年   171篇
  1995年   102篇
  1994年   78篇
  1993年   108篇
  1992年   27篇
  1991年   23篇
  1990年   16篇
  1989年   27篇
  1988年   26篇
  1987年   16篇
  1986年   15篇
  1985年   24篇
  1984年   9篇
  1983年   11篇
  1982年   24篇
  1981年   32篇
  1980年   39篇
  1979年   16篇
  1978年   27篇
  1977年   105篇
  1976年   199篇
  1975年   18篇
  1974年   17篇
  1973年   17篇
  1972年   9篇
  1971年   14篇
  1966年   8篇
排序方式: 共有2384条查询结果,搜索用时 323 毫秒
1.
Power Technology and Engineering - The work done on the test site to ensure the operational safety of the powerhouse of the Zagorsk PSP-2 after its leveling is described. The controlled...  相似文献   
2.
Power Technology and Engineering - The major results from the survey and geotechnical monitoring during the leveling of the model foundation of the Zagorsk PSP-2 in test site No. 3 are presented....  相似文献   
3.
4.
Vascular injuries may occur as complications of elbow dislocation and usually involve the brachial artery. A case report is presented in which only the radial artery was compromised as a result of the dislocation.  相似文献   
5.
The paper analyzes left ventricular structure-fraction relationships in the development of postinfarct aneurysm. The altered internal architectonics induces to systemic hemodynamic changes, drastically elevated intraventricular pressure. This is caused by to the dysfunction of the papillary-trabecular complex in the left ventricular cavity, which in turn. This leads to the fact that the heart work as a positive-displacement pump, by losing its capacity as a centrifugal component, by making the myocardium require additional energy expenditures, which in turn appears as varying heart failure. This investigation is of definite practical value in developing adequate correction methods for postinfarct aneurysm which can occur with the retained or formed certain ratios of cardiac structures.  相似文献   
6.
An analysis of papers on hydrogen combustion at low pressures is performed, which refines the contribution of the catalytic reactions on the reactor wall to the gas-phase part of the process. A new model for the heterogeneous loss of active reaction centers was proposed and tested experimentally to explain inconsistencies that occur in some papers. In this model, the diffusion region of chain termination is formed under standard experimental conditions in vacuum oxyhydrogen flames at a reactor gas pressure a thousand times lower than the boundary pressure postulated by the previous models as the pressure below which the diffusion region of chain termination cannot be formed. __________ Translated from Fizika Goreniya i Vzryva, Vol. 42, No. 2, pp. 10–18, March–April, 2006.  相似文献   
7.
The theory of separation, based on radial averaging, in a Zippe centrifuge is developed. Certain aspects of the theory of the rotational potential and the errors in understanding the essence of the Helmholtz decomposition as it applies to a gas centrifuge are elucidated. It is shown that the Helmholtz decomposition method does not have cetain drawbacks of the classical theory of the radial averaging method and makes it possible to take account of the rotational flows due to the feed, find expicitly the transit flow distribution, take account of the radial nonuniformity, and take account of the radial convective transport of an isotope by the circulation and transit flows, and the method is not limited by the assumption that the feed flow is small.  相似文献   
8.
The possibilities of using influenza A (Leningrad) 385/80 (H3N2) virus matrix protein-specific FITC-labeled D8 monoclonal antibodies in immunofluorescence assays were investigated. The virus antigen accumulation was detected in chorioallantoic cells of chick embryos. Exhibiting the type-specific properties, the fluorescent antibodies stain the perinuclear space, cytoplasmic membrane, and granular structures in the cytoplasm of infected cells. The haemagglutination test tires in the corresponding specimens were at least 1:16.  相似文献   
9.
Echo-planar techniques in MRI use a rapidly oscillating frequency-encoding gradient with the potential to produce peripheral nerve stimulation. To evaluate the incidence, type, and location of stimulation in a commercial whole-body scanner, we studied two groups: (a) 173 consecutive individuals scanned by echo-planar imaging for other purposes and (b) seven subjects who were scanned with an extensive set of 36 echo-planar sequences (with prompting after each scan to report any peripheral nerve stimulation) to test the effects of various parameters. Although only 5% of group A reported symptoms of peripheral nerve stimulation, all in group B experienced some type of stimulation, dependent primarily on direction of the oscillating gradient and location of the body within the gradient coil. Maximum stimulation typically occurred 30 to 40 cm from isocenter in the region of maximum dB/dt. Generally, y gradients produced truncal stimulation, and x gradients produced stimulation in the head. When hands were clasped over the abdomen, a tingling in the hands occasionally was felt. Patients should be instructed to keep their hands apart.  相似文献   
10.
The results of the comparative study of the phenotypical properties and the plasmid profile of 63 strains of salmonellae, belonging to 44 serotypes of groups B, C1, C2, C3, D, E1, E4, F. The study revealed that strains of different serotypes had their individual plasmid profile. Strains of the same serotype of salmonellae isolated from similar sources had an identical plasmid profile, while strains isolated from different sources differed in their plasmid profiles, though they might have a similar phenotype. Plasmid analysis was shown to be an effective method for the intraspecific typing of rarely isolated Salmonella serotypes and suitable for use as the basis of the microbiological monitoring of salmonellae.  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