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   314篇
  免费   8篇
  国内免费   1篇
电工技术   11篇
化学工业   47篇
金属工艺   23篇
机械仪表   15篇
能源动力   13篇
轻工业   20篇
无线电   41篇
一般工业技术   45篇
冶金工业   75篇
原子能技术   8篇
自动化技术   25篇
  2023年   2篇
  2022年   1篇
  2021年   6篇
  2019年   1篇
  2018年   4篇
  2017年   5篇
  2016年   3篇
  2015年   6篇
  2014年   3篇
  2013年   21篇
  2012年   13篇
  2011年   15篇
  2010年   10篇
  2009年   16篇
  2008年   16篇
  2007年   12篇
  2006年   9篇
  2005年   8篇
  2004年   5篇
  2003年   11篇
  2002年   3篇
  2001年   10篇
  2000年   7篇
  1999年   10篇
  1998年   30篇
  1997年   24篇
  1996年   8篇
  1995年   8篇
  1994年   4篇
  1993年   6篇
  1992年   4篇
  1991年   1篇
  1990年   1篇
  1989年   2篇
  1988年   2篇
  1987年   2篇
  1986年   1篇
  1984年   2篇
  1983年   2篇
  1982年   1篇
  1981年   6篇
  1980年   4篇
  1979年   1篇
  1978年   3篇
  1977年   6篇
  1976年   5篇
  1975年   1篇
  1974年   1篇
  1970年   1篇
排序方式: 共有323条查询结果,搜索用时 15 毫秒
41.
A new algorithm to find recurrence relations of binomial sums and a complexity analysis are given. The algorithm is based on the theory of hypergeometric functions and algorithmic method to get contiguity relations of hyperegeometric functions.  相似文献   
42.
43.
Recent preventive maintenance for equipment has grown to include diagnosis of the insulation of cables under hot-line conduction. Much of the equipment constructed during the high-growth period in the 1960s has become obsolete. Recent circumstances make it difficult to obtain a longer service interruption time. Results of a study of the method that measures the live-wire insulation resistance by superimposing dc 50 V to a high-voltage busbar through GPT and forms a bridge with the resistance of a cable insulation are discussed. It is clarified that this live-wire insulation diagnostic method is highly effective at detecting degradation of a cable insulation resistance and is, therefore, suitable for so-called trend monitoring as well.  相似文献   
44.
Functional magnetic resonance imaging (fMRI) was performed using a clinical 1.5 T MR scanner. Normal volunteers and patients with several neurological disorders were studied with somatosensory stimulation using sponge at right hand and visual stimulation using checkerboard pattern. Both fMR images by gradient echo echo planar imaging and three dimensional gradient echo images were studied. Reconstructed 3 dimensional functional brain mapping was superimposed on 3D anatomical images. Apparent signal increase was observed at contra lateral sensorimotor cortex and secondary sensory cortex with sponge stimulation. In the case of left homonymous hemianopia due to cerebral infarction, increasing signal was only observed surrounding left calcarine fissure by using stimulation of all visual field. In conclusion, fMRI and 3-D functional brain mapping has extremely high potentiality to examine pathophysiology of various neurological disorders.  相似文献   
45.
The paper discusses some of the factors that affect the onset of osteoporosis, and provides an original model for rehabilitation procedure in this disorder. The type of motor exercises used are indicated, and the sequence in which they are done. There is also a discussion of the significance of the application of physiotherapy equipment. Attention is also drawn in the paper to the possibility of the patient applying rehabilitation procedures independently, under only periodic supervision by the physician.  相似文献   
46.
Industrial production of L ‐lactic acid, which in polymerized form as poly‐lactic acid is widely used as a biodegradable plastic, has been attracting world‐wide attention. By genetic engineering we constructed a strain of the Crabtree‐negative yeast Candida boidinii that efficiently produced a large amount of L ‐lactic acid. The alcohol fermentation pathway of C. boidinii was altered by disruption of the PDC1 gene encoding pyruvate decarboxylase, resulting in an ethanol production that was reduced to 17% of the wild‐type strain. The alcohol fermentation pathway of the PDC1 deletion strain was then successfully utilized for the synthesis of L ‐lactic acid by placing the bovine L ‐lactate dehydrogenase‐encoding gene under the control of the PDC1 promoter by targeted integration. Optimizing the conditions for batch culture in a 5 l jar‐fermenter resulted in an L ‐lactic acid production reaching 85.9 g/l within 48 h. This productivity (1.79 g/l/h) is the highest thus far reported for L ‐lactic acid‐producing yeasts. DDBJ/EMBL/GenBank nucleotide database with Accession Nos. AB440630 and AB440631. Copyright © 2009 John Wiley & Sons, Ltd.  相似文献   
47.
An approach by task assignment is presented to determine processing system structures in chemical process design. For given design conditions of major subsystems, which were specified by the results of basic or applied research, a basic flowsheet is determined by task assignments on energy recovery and material flow transportation. An illustrative example shows the usefulness of the present method.  相似文献   
48.
49.
50.
A 52-year-old male gardener, who traveled to Guam Island several days ago, was admitted to our hospital with fever, cough and dyspnea. His chest X-ray showed bilateral infiltration and he was severely hypoxic and hypotensive on admission. He died of multiple organ failure in spite of intensive treatment with mechanical ventilation antibiotics including erythromycin. Legionella longbeachae serotype 1 was isolated from his sputum and was regarded as the etiologic agent. Legionella longbeachae was not isolated from the same type of leaf mold that he used as potting soil. This is the first case of Legionella longbeachae pneumonia from whom the organism was isolated in Japan.  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