全文获取类型
收费全文 | 688篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 18篇 |
化学工业 | 163篇 |
金属工艺 | 84篇 |
机械仪表 | 30篇 |
建筑科学 | 5篇 |
矿业工程 | 3篇 |
轻工业 | 26篇 |
水利工程 | 8篇 |
石油天然气 | 60篇 |
武器工业 | 4篇 |
无线电 | 38篇 |
一般工业技术 | 114篇 |
冶金工业 | 99篇 |
原子能技术 | 31篇 |
自动化技术 | 12篇 |
出版年
2022年 | 16篇 |
2021年 | 28篇 |
2020年 | 15篇 |
2019年 | 13篇 |
2018年 | 15篇 |
2017年 | 24篇 |
2016年 | 32篇 |
2015年 | 8篇 |
2014年 | 17篇 |
2013年 | 24篇 |
2012年 | 21篇 |
2011年 | 27篇 |
2010年 | 20篇 |
2009年 | 18篇 |
2008年 | 24篇 |
2007年 | 33篇 |
2006年 | 19篇 |
2005年 | 13篇 |
2004年 | 17篇 |
2003年 | 13篇 |
2002年 | 11篇 |
2000年 | 15篇 |
1999年 | 8篇 |
1998年 | 13篇 |
1997年 | 12篇 |
1996年 | 13篇 |
1995年 | 6篇 |
1993年 | 11篇 |
1992年 | 6篇 |
1991年 | 7篇 |
1990年 | 8篇 |
1989年 | 7篇 |
1987年 | 10篇 |
1986年 | 9篇 |
1985年 | 7篇 |
1983年 | 7篇 |
1981年 | 6篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 8篇 |
1977年 | 8篇 |
1976年 | 17篇 |
1975年 | 6篇 |
1974年 | 6篇 |
1972年 | 5篇 |
1971年 | 7篇 |
1970年 | 10篇 |
1969年 | 9篇 |
1967年 | 6篇 |
1966年 | 6篇 |
排序方式: 共有695条查询结果,搜索用时 15 毫秒
111.
112.
The isoenzyme composition of lactate dehydrogenase of soleus and plantaris muscles of rats flown for 20.5 d aboard the biosatellite Cosmos-690 and irradiated with a dose of 800 rad was investigated. The muscles exposed to weightlessness per se and weightlessness combined with radiation showed similar changes in their carbohydrate metabolism. On return to 1 G, readaptation of irradiated rats developed less rapidly than of animals exposed to weightlessness alone. 相似文献
113.
VG Petrova 《Canadian Metallurgical Quarterly》1976,71(8):57-65
A comparative study of the cytological characteristics of the epithelial lining of the nephron and collecting tubules was performed in 9 species of reptiles, 19 species of birds and 12 species of mammals. Representatives of each class of higher vertebrates were shown to have certain specific features of the epithelial lining of different parts of the nephron. Differentiation of various areas of the proximal part of the nephron proceded in phylogeny with different intensity and the maximum specialization was characteristic of the most proximal portion of this part of the nephron. In the cells of the proximal parts of nephrons of some reptiles there were phenomena of apocrine secretion. Evolution of the distal part of the nephron developed to form a loop and differentiation of the distal convoluted segment. The higher differentiation of the epithelial lining of the nephron distal part in birds and mammals, unlike in reptiles, seems to be associated with a more considerable functional specilization of this part. In the cytochemical characteristics of the epithelium of the uriniferous and collecting tubules of kidneys of higher vertebrate animals there are common regularities in the distribution of RNA, proteins and some enzymes. The polysaccharide content is maximum in the epithelial cells of kidneys of reptiles. 相似文献
114.
115.
Conclusions At present the Soviet instrument designers have an extensive available range of torsion suspensions for measuring instruments made according to GOST 9444-60 of four materials with any required values of restoring torque, in the range of 0.01 to 20 mg-wt·cm/90° and a length of 100 mm.These torsion suspensions have physical and mechanical properties which meet various requirements raised by modern electrical instrument-making techniques.On the basis of experiments conducted by us we can recommend for high precision, vibration- and shockproof instruments with a large angle of twist, operating in tropical conditions or corrosive media, torsion suspensions types PtAg20 and Co40NiCrMoV, which are extremely strong, elastic and corrosionproof.However, suspensions types PtAg20 cannot be used if a small thermal emf is required between it and copper, and those of type Co40NiCrMoV cannot be used when a high electrical conductivity is required.In electrostatic instruments where suspensions are heated up considerably by the capacitative current it is advisable to use beryllium torsion suspensions.These suspensions cannot be used, however, in precision instruments, since they have a high elastic fatigue after twisting.Torsion suspensions made of BrSnZn4-3 can be widely used in high precision instruments of the most varied types, provided they are not required to be very strong mechanically and highly resistant to oxidation and corrosion. 相似文献
116.
117.
118.
119.
120.