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   1140篇
  免费   12篇
电工技术   13篇
综合类   1篇
化学工业   43篇
金属工艺   3篇
机械仪表   11篇
建筑科学   6篇
矿业工程   1篇
能源动力   4篇
轻工业   11篇
水利工程   3篇
无线电   9篇
一般工业技术   34篇
冶金工业   973篇
原子能技术   2篇
自动化技术   38篇
  2022年   5篇
  2021年   2篇
  2020年   3篇
  2019年   2篇
  2018年   4篇
  2017年   4篇
  2016年   4篇
  2015年   7篇
  2014年   3篇
  2013年   10篇
  2012年   9篇
  2011年   15篇
  2010年   11篇
  2009年   3篇
  2008年   6篇
  2007年   13篇
  2006年   6篇
  2005年   10篇
  2004年   15篇
  2003年   11篇
  2001年   2篇
  1999年   28篇
  1998年   273篇
  1997年   155篇
  1996年   115篇
  1995年   71篇
  1994年   51篇
  1993年   57篇
  1992年   8篇
  1991年   14篇
  1990年   14篇
  1989年   15篇
  1988年   12篇
  1987年   11篇
  1986年   16篇
  1985年   4篇
  1983年   5篇
  1982年   4篇
  1981年   9篇
  1980年   9篇
  1979年   1篇
  1978年   2篇
  1977年   45篇
  1976年   80篇
  1975年   1篇
  1970年   1篇
  1966年   1篇
  1965年   1篇
  1962年   1篇
  1955年   1篇
排序方式: 共有1152条查询结果,搜索用时 0 毫秒
81.
The case of a 40-year-old male patient with obstructive sleep apnea syndrome (OSAS) is reported, with emphasis on treatment with a dental appliance. This therapeutic approach, which has been focused on recent research, has as its objective, the posturing of the mandibule and, consequently, the tongue more anteriorly, thus in turn leading to an increase in the posterior oropharyngeal airway space (PAS). Cephalometry contributed determining in this case whereby enlargement limits were observed in the PAS with mandibular displacement. Clinical and polysomnographic controls showed subjective reduction of the excessive daytime sleepiness and objective decrease in apneas intensity to normal limits. Eight months follow-up evidenced the steady improvement.  相似文献   
82.
Protein complexes present different degrees of stability. We have previously described a glycoprotein from Bacillus thuringiensis that appeared as a multimer unable to be dissociated by the usual SDS-containing sample buffers of pH 6.8. In order to dissociate the complex, a SDS-containing sample buffer of pH 9 was described. In the present report three additional protein complexes with different degrees of stability and the effect of that dissociating sample buffer are described. The study of SDS critical micellar concentration values as a function of pH explains the improvement of dissociating properties at pH 9.  相似文献   
83.
In the present study DNA from 281 unrelated haemophilia A patients including 15 inhibitor patients has been analysed by Southern blotting technique. Using various restriction enzymes, cloned factor VIII cDNA probes and genomic fragments we have identified 14 mutations. Six of the mutations are novel partial factor VIII gene deletions. One deletion affects exon 1, two deletions concern exon 6, another deletion, of which breakpoints are sequenced, takes part of exon 16 and two deletions affect exon 26. Besides the deletions, eight point mutations have been found at the TaqI restriction sites of exons 18, 24 and 26. Five C-->T mutations resulted in nonsense mutations, one in exon 18, one in exon 26 and three in exon 24. Two G-->A mutations caused a missense mutation in exon 24 leading to an arginine/glutamine exchange. Although two patients showed this mutation, their clinical phenotypes were different, possibly due to an additional unidentified sequence polymorphism. A G-->T mutation in exon 26 substituted the arginine with leucine. All deletions and seven of the point mutations are associated with severe disease with a detectable inhibitor in the patient with the TaqI-point mutation in exon 18. One of the G-->A mutations is associated with mild haemophilia but the patient also has developed an inhibitor. Amongst these mutations the origin of the mutation could be determined in four kindred, one of which showed maternal mosaicism.  相似文献   
84.
In order to carry out investigations in the course of sport activities of children an efficient telemetering device is essential, which can also be used on children. The Kinderspital Salzburg has developed a telemetry system in cooperation with the Technische Versuchs- und Forschungsanstalt der Technischen Hochschule Wien and the Messerschmitt-B?lkow-Blohm-Werke München. For the first time in this field a Pulse Code Modulation (P.C.M.) System was utilized, implying high accuracy on data transmission and recovery as required for scientific examinations. The children's physical capacity is determined on a bicycle ergometer, and the performance measured in this fashion is then compared with the performance achieved in sport.  相似文献   
85.
Prolonged and monosymptomatic dysphasic status epilepticus   总被引:1,自引:0,他引:1  
Dysphasic seizures are an infrequent form of epilepsy, and their serial appearance as a partial status epilepticus is quite exceptional. The young patient reported here had a partial dysphasic status epilepticus of 3 weeks' duration without other temporal lobe seizures. Simultaneous serial electroencephalograms, tape recordings of the seizures, and repeated neuropsychologic ictal examinations permitted studies of increased impairment of neuropsychologic function on testing and the appearance of new irritative discharges on encephalography.  相似文献   
86.
Disulfiram treatment caused marked elevations of circulating blood acetone levels in rat and man. In the rat, disulfiram (0.59 g/kg, p.o.) given singly or for three consecutive days increased the fasting blood acetone levels 5- and 25-fold, fespectively. Circulating acetone levels were also estimated noninvasively in man by measuring acetone in the expired air. A 15-fold increase in the expired air acetone levels was observed in a group of five male non-fasting subjects taking disulfiram (250 mg daily) for a minimum of one month, when compared to control subjects.  相似文献   
87.
Independent intracellular activation of any one of the five identified neurones elicits a behavioral act of pneumostome closing. Similar closing is evoked by adequate stimulation of different modalities. Comparison of unconditioned reflex properties and characteristics of responses of the studied cells leads to the conclusion that neurones under discussion are command elements for the unconditioned reflex. Command neurones respond to all sensory stimuli which can evoke reflex closing. There is a lot of synchronous EPSPs in their spontaneous activity, but no action potentials. A spike discharge of command neurones evoked by an adequate stimulus always precedes the effector movements but there is no action potentials during the pneumostome closing. Conclusion is made that the functional role of command neurones in the unconditioned reflex arc consists in evaluating the sensory input and in triggering motor programmes.  相似文献   
88.
89.
90.
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