全文获取类型
收费全文 | 2230篇 |
免费 | 3篇 |
专业分类
电工技术 | 10篇 |
化学工业 | 97篇 |
金属工艺 | 35篇 |
机械仪表 | 47篇 |
建筑科学 | 5篇 |
矿业工程 | 14篇 |
能源动力 | 5篇 |
轻工业 | 7篇 |
水利工程 | 10篇 |
石油天然气 | 57篇 |
无线电 | 50篇 |
一般工业技术 | 202篇 |
冶金工业 | 1625篇 |
原子能技术 | 46篇 |
自动化技术 | 23篇 |
出版年
2021年 | 10篇 |
2020年 | 12篇 |
2019年 | 13篇 |
2018年 | 24篇 |
2017年 | 30篇 |
2016年 | 28篇 |
2015年 | 9篇 |
2014年 | 27篇 |
2013年 | 35篇 |
2012年 | 28篇 |
2011年 | 43篇 |
2010年 | 30篇 |
2009年 | 21篇 |
2008年 | 27篇 |
2007年 | 27篇 |
2006年 | 9篇 |
2005年 | 11篇 |
2004年 | 17篇 |
2003年 | 16篇 |
2002年 | 12篇 |
2001年 | 21篇 |
2000年 | 13篇 |
1999年 | 35篇 |
1998年 | 416篇 |
1997年 | 258篇 |
1996年 | 169篇 |
1995年 | 98篇 |
1994年 | 80篇 |
1993年 | 102篇 |
1992年 | 15篇 |
1991年 | 15篇 |
1990年 | 13篇 |
1989年 | 10篇 |
1988年 | 15篇 |
1987年 | 14篇 |
1986年 | 9篇 |
1985年 | 9篇 |
1982年 | 28篇 |
1981年 | 28篇 |
1980年 | 36篇 |
1979年 | 8篇 |
1978年 | 10篇 |
1977年 | 99篇 |
1976年 | 199篇 |
1975年 | 13篇 |
1971年 | 7篇 |
1970年 | 9篇 |
1969年 | 7篇 |
1967年 | 9篇 |
1965年 | 6篇 |
排序方式: 共有2233条查询结果,搜索用时 15 毫秒
71.
30 patients were exposed to interference currents (IC) alone (group 1) versus 34 patients treated with IC plus iodobromine baths (group 2). After IC action on the region of the kidney projection patients of group 1 experienced positive changes in cellular and humoral immunity providing an antiinflammatory effect. In group 2, the improvement was seen in renal and urinary functions, 24-h urinary excretion of oxalates and calcium diminished. Interference current proved beneficial in chronic pyelonephritis patients with latent inflammation. The combined therapy was effective in patients at high risk of lithogenesis. 相似文献
72.
73.
74.
AA Bakova BD Brondz OA Fedorkina VA Gusev AI Gordienko IuS Krivoshein IuL Krivorutchenko TG Prokopenko IA Popov 《Canadian Metallurgical Quarterly》1994,39(4):187-189
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
75.
VA Lumley RG Miltenberger ES Long JT Rapp JA Roberts 《Canadian Metallurgical Quarterly》1998,31(1):91-101
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
76.
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
77.
S. A. Sidorov D. A. Mironov V. K. Khoroshenkov E. I. Khlusova 《Welding International》2016,30(10):808-812
The rapid wear of working tools of agricultural machines and equipment lowers the productivity of labour and the quality of operations. The most important and, correspondingly, most ‘problematic’ loaded components of agricultural machines are soil cultivating working tools. The principal methods of increasing the service life of these components are to use new materials and hardening surfacing technologies. 相似文献
78.
S. N. Anuchkin V. T. Burtsev M. V. Zagumennikov V. V. Sidorov V. E. Rigin 《Russian Metallurgy (Metally)》2010,(5):371-374
The density of melts based on nickel of various grades (i.e., with various oxygen contents) is experimentally studied at 1500–1650°C
and p
Ar = 0.1 MPa, and the effect of alloying elements (Al, Re, W, Mo, Co) on this density is analyzed. As compared to liquid nickel,
the density of a Ni-6% Al melt decreases and that of Ni-(3–7)% Re and Ni-7% Re-(W,Mo,Co) melts increases. The difference between
the molar volume of the melt calculated from the experimental data and using the additivity rule is determined, and the structures
of the melts at 1823 K are found to have a low density. 相似文献
79.
80.
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