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   517篇
  免费   3篇
电工技术   1篇
化学工业   40篇
金属工艺   3篇
机械仪表   6篇
矿业工程   10篇
轻工业   3篇
水利工程   1篇
石油天然气   14篇
无线电   9篇
一般工业技术   75篇
冶金工业   330篇
原子能技术   14篇
自动化技术   14篇
  2022年   3篇
  2021年   8篇
  2017年   3篇
  2016年   3篇
  2012年   2篇
  2011年   3篇
  2010年   2篇
  2009年   2篇
  2008年   7篇
  2007年   6篇
  2006年   5篇
  2004年   4篇
  2003年   6篇
  2002年   2篇
  2000年   3篇
  1999年   5篇
  1998年   76篇
  1997年   53篇
  1996年   34篇
  1995年   20篇
  1994年   21篇
  1993年   14篇
  1992年   11篇
  1991年   5篇
  1990年   5篇
  1989年   5篇
  1988年   5篇
  1987年   11篇
  1986年   8篇
  1985年   6篇
  1984年   5篇
  1983年   4篇
  1982年   8篇
  1981年   2篇
  1980年   11篇
  1979年   6篇
  1978年   11篇
  1977年   33篇
  1976年   51篇
  1975年   4篇
  1974年   5篇
  1973年   4篇
  1972年   2篇
  1971年   2篇
  1970年   3篇
  1962年   3篇
  1960年   8篇
  1959年   2篇
  1958年   5篇
  1956年   2篇
排序方式: 共有520条查询结果,搜索用时 15 毫秒
1.
2.
Modern designs are examined, and technical data presented for vibratory electric and convection driers, driers with infra-red sources, and steam driers.  相似文献   
3.
A model of human neonatal ovary is presented, derived from morphometric, evaluations carried out on left ovaries removed from five full-term neonates with a 46, XX karyotype, free from malformations of the genital apparatus. According to this model, the gonad can be represented by a triaxial ellipsoid with a central medullary core surrounded by a cortical stratum of constant thickness. The germinal population, consisting of follicles and primitive cortical tissue, occupies the cortex, intermingled with the interstitium or stroma. In the cortex it is then possible to describe an outer layer formed by primitive cortical tissue, and an inner portion occupied by follicles. The primary and secondary follicles fill the portion near the medulla and the primordial ones are contained in the middle and outer zones. Since the variability observed among ovaries is slight, we can propose a mean model of neonatal ovary in which the spatial relationships among the different components, the total number of follicles and their position in the cortex can be calculated.  相似文献   
4.
2400-year solar cycle ascertained by us in the long-term series of various natural characteristics (e.g. the radiocarbon content in samples of well-known ages, oscillations of the sea and ocean levels etc.) includes three parts roughly equal in duration: a phase of high activity, a phase of depression and a phase of moderate activity. In climate oscillations, which are connected with this cycle, the next phenomena are established: a little climatic optimum, a little Ice Age, and a temperate climate epoch.  相似文献   
5.
Jet injection can be used to introduce genes into the cells of differentiated tissues of living animals and organ cultures. When a solution of plasmid DNA is jet injected into a selected tissue or organ, cells lying in or near the path of the jet injection are transfected with the DNA and the introduced gene(s) are expressed. Since there is minimal morbidity from each jet injection, multiple injections can be performed at the same or nearby sites. Both mRNA and protein expression from transfected genes can be quantitated using standard methods. In addition, the technique is an efficient means of DNA immunization. Methodology for using jet injection to transfer plasmid DNA into the cells of skin, fat, mammary gland, and muscle are described.  相似文献   
6.
The results of clinical and laboratory studies on the use of augmentin in severe purulent complications after neurosurgical operations are presented. The laboratory studies carried out with the use of an automatic system Cobas Bact (Roch) showed that the numbers of the augmentin resistant strains of Staphylococcus and Enterobacteriaceae among the pathogens were 47 and an average of 64.5%, respectively. Gram-negative bacteria resistant to augmentin were 1.5 to 2 times less frequent than those resistant to amoxycillin. Still, they were much more frequent than those resistant to cefotaxime and ceftriaxone. Clinical efficacy of augmentin was studied in treatment of 39 patients with various affections of the brain such as tumors, trauma, vascular malformations and inflammatory processes. The postoperative complications were represented by meningitis, pneumonia, sepsis and their associations. The use of augmentin in the severe intra- and extracranial complications was favourable in 82.1% of the cases.  相似文献   
7.
8.
9.
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