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   1551篇
  免费   1篇
电工技术   1篇
化学工业   4篇
金属工艺   5篇
机械仪表   1篇
轻工业   5篇
一般工业技术   10篇
冶金工业   1525篇
自动化技术   1篇
  2015年   1篇
  2013年   2篇
  2012年   2篇
  2007年   1篇
  2005年   1篇
  2004年   4篇
  2003年   2篇
  2002年   1篇
  1999年   25篇
  1998年   405篇
  1997年   252篇
  1996年   166篇
  1995年   94篇
  1994年   74篇
  1993年   100篇
  1992年   9篇
  1991年   13篇
  1990年   7篇
  1989年   7篇
  1988年   7篇
  1987年   9篇
  1986年   7篇
  1985年   7篇
  1983年   2篇
  1982年   14篇
  1981年   22篇
  1980年   28篇
  1979年   3篇
  1978年   4篇
  1977年   91篇
  1976年   183篇
  1975年   7篇
  1973年   1篇
  1955年   1篇
排序方式: 共有1552条查询结果,搜索用时 15 毫秒
51.
52.
53.
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   
54.
We have measured the Fourier transform spectrum of natural OCS from 3700 to 4800 cm-1 with a near Doppler resolution and a line-position accuracy between 4 and 8 x 10(-5) cm-1. For the normal isotopic species, 37 vibrational transitions have been analyzed for both frequencies and intensities. We also report 15 bands of OC34S, eight bands of O13CS, nine bands of OC33S, and two bands of 18OCS. Important effective Herman-Wallis terms are explained on the basis of eigenvectors. A comparison of different line-pointing programs is also presented. Copyright 1998 Academic Press.  相似文献   
55.
The vigilance reaction is characterized by a large bradycardia, a pressor response, and inspiratory apnea in anesthetized rabbits and the inhibition of movement in conscious rabbits. This affective response pattern can be elicited by electrical stimulation of the dorsolateral hypothalamus (the hypothalamic vigilance area) or the ventrolateral periaqueductal gray (the periaqueductal gray vigilance area). The present study sought to advance our understanding of the functional relationship between the hypothalamic vigilance area (HVA) and the periaqueductal gray vigilance area (PVA) by measuring the effects of transverse transections of the caudal portion of the ventrolateral PAG (vlPAG) upon the cardiovascular responses elicited from the dorsolateral hypothalamus and the rostral vlPAG. Selective transverse transections of the caudal vlPAG significantly reduced the magnitudes of the bradycardia and pressor response elicited by stimulation of the PVA rostral to the transection site, but had minimal impact on the cardiovascular responses evoked by stimulation of the HVA. These findings suggest that the cardiovascular responses elicited by stimulation of the vlPAG are mediated by a neural pathway that is parallel, at least in part, to the one that subserves the response elicited from the HVA. The results also provide support for the view that the PAG is not an essential structure in the mediation of the autonomic components of affective behaviors involving behavioral inhibition.  相似文献   
56.
The essential fatty acid arachidonate is oxidized by cytochrome P-450 epoxygenases to four epoxyeicosatrienoic acids (EETs): 14,15-, 11,12-, 8,9-, and 5,6-EETs. Each of the four EET regioisomers and their hydrolysis products (DHETs) has multiple paracrine and autocrine functions and may also potently dilate blood vessels and activate potassium channels. The present work describes a method to resolve EETs and DHETs by capillary electrophoresis (CE) using trimethyl-beta-cyclodextrin and CH3CN as buffer additives. While stored at 25 degrees C, most of the EET and DHET regioisomers remained intact when suspended in alkaline vehicle. However, under these same conditions, 5,6-EET rapidly broke down to a lactone and was slowly converted to 5,6-DHET. When subjected to CE, the EET and DHET regioisomers were baseline resolved (R > or = 1.3); 10 pg of an EET or a DHET regioisomer was readily detectable at 194 nm. In addition, the UV spectra were regiospecific and identical to those obtained during HPLC except that an additional, weak absorption occurred at 235 nm. Together, the high-sensitivity, high-resolution, and differential UV spectra permitted the identification and quantification of EETs in phospholipids isolated from murine liver. Thus, CE was successfully used for the trace analysis of eicosanoids.  相似文献   
57.
58.
The changes of bioelectric activity of the brain hemispheres were studied under the influence of an alternating magnetic field (AMF), directed on the hand of 20 epileptic patients and 18 healthy normals. Under AMF influence there was intensification of epileptic activity--elevation of the focal bioelectric characteristics and of the processes of generalization. It permitted to apply AMF for diagnosis of epileptic focus. Under AMF influence more stable changes in posterio-parietal areas of the right hemisphere occur. The authors came to the conclusion that AMF effects were mainly realized with participation of right hemisphere.  相似文献   
59.
5-HT4 receptors are concentrated in areas of the brain which are rich in dopamine neuronal markers, which may suggest that they influence motor and reward processes. We tested this hypothesis by examining the effects of a 5-HT4 receptor antagonist, 8-amino-7-chloro-(N-butyl-4-piperidyl)methylbenzo-1,4-dioxan-5-car boxylate hydrochloride (SB-204070-A) on amphetamine- and nicotine-induced locomotor stimulation in intact rats. In rats with unilateral 6-hydroxydopamine-induced lesions of the ascending nigrostriatal dopaminergic projection, SB-204070-A was tested for its effects on amphetamine-induced rotation. SB-204070-A was also tested for its effects on rewarded behaviour maintained by intracranial self-stimulation. SB-204070-A did not alter behaviour under any of these conditions, suggesting a lack of involvement of the 5-HT4 receptor in motor and reward processes.  相似文献   
60.
Features were studied of brain organization of mental processes in schizophrenic patients during the period of aggravation of the condition, using methods common in neuropsychological diagnosis. Faulty mental functions are analyzed in connection with clinical manifestations. Groups have been identified of patients having particular neuropsychological and clinical characteristics.  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