全文获取类型
收费全文 | 911篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 7篇 |
综合类 | 1篇 |
化学工业 | 169篇 |
金属工艺 | 17篇 |
机械仪表 | 15篇 |
建筑科学 | 62篇 |
矿业工程 | 5篇 |
能源动力 | 39篇 |
轻工业 | 63篇 |
水利工程 | 7篇 |
石油天然气 | 1篇 |
无线电 | 50篇 |
一般工业技术 | 161篇 |
冶金工业 | 240篇 |
原子能技术 | 7篇 |
自动化技术 | 108篇 |
出版年
2023年 | 8篇 |
2022年 | 11篇 |
2021年 | 9篇 |
2020年 | 9篇 |
2019年 | 12篇 |
2018年 | 27篇 |
2017年 | 27篇 |
2016年 | 18篇 |
2015年 | 11篇 |
2014年 | 24篇 |
2013年 | 49篇 |
2012年 | 27篇 |
2011年 | 44篇 |
2010年 | 40篇 |
2009年 | 38篇 |
2008年 | 51篇 |
2007年 | 32篇 |
2006年 | 35篇 |
2005年 | 32篇 |
2004年 | 26篇 |
2003年 | 24篇 |
2002年 | 24篇 |
2001年 | 21篇 |
2000年 | 12篇 |
1999年 | 14篇 |
1998年 | 66篇 |
1997年 | 36篇 |
1996年 | 32篇 |
1995年 | 11篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 4篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1983年 | 8篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 6篇 |
1979年 | 7篇 |
1978年 | 10篇 |
1977年 | 8篇 |
1976年 | 5篇 |
1975年 | 7篇 |
1974年 | 7篇 |
1973年 | 5篇 |
排序方式: 共有952条查询结果,搜索用时 31 毫秒
1.
2.
A. A. Salem S. R. Kalidindi R. D. Doherty S. L. Semiatin 《Metallurgical and Materials Transactions A》2006,37(1):259-268
Novel experiments were conducted to elucidate the effect of deformation twinning on the mechanical response of high-purity
α-titanium deformed at room temperature. Orientation-imaging microscopy (OIM), microhardness, and nanohardness evaluations
were employed in conjunction with optical microscopy and quasi-static compression testing to obtain insight into the deformation
mechanisms. Hardness measurements revealed that the newly formed deformation twins were harder than the matrix. This observation
is perhaps the first experimental evidence for the Basinski mechanism for hardening associated with twinning, arising from
the transition of glissile dislocations to a sessile configuration upon the lattice reorientation by twinning shear. This
work also provided direct evidence for two competing effects of deformation twinning on the overall stress-strain response:
(1) hardening via both a reduction of the effective slip length (Hall-Petch effect) and an increase in the hardness of twinned regions (Basinski
mechanism) and (2) softening due to the lattice reorientation of the twinned regions. 相似文献
3.
O Doherty M Booth N Waran C Salthouse D Cuddeford 《Canadian Metallurgical Quarterly》1997,141(23):589-592
The energy expenditure and heart rate of five Shetland ponies were measured during transport and compared with the values recorded while they were at rest and walking. Secondary aims of the study were to investigate whether there was any correlation between heart rate and energy expenditure and whether different orientations affected the values to different degrees. The measurements were recorded at one-minute intervals while the ponies were at rest, walking and being transported in four different orientations, on journeys lasting 30 minutes. There were significant increases (P < 0.001) in both heart rate and energy expenditure during transport which were similar to those associated with walking, and there was a strong correlation between the two measurements. There was no conclusive evidence that orientation affected the measurements, but it appeared that rear facing transport might have had the least effect. 相似文献
4.
5.
Isolated rat hearts were subjected to 15, 45, or 60 minutes of global ischaemia and then fixed by perfusion at 37°C with glutaraldehyde containing various amounts of oxygen. This either had been bubbled with 100% oxygen (PO2 620 mm Hg) or with 100% nitrogen (PO2 40 mm Hg) immediately before use, or it had been routinely prepared and stored exposed to atmospheric oxygen (PO2 245 mm Hg). The ultrastructure of myocytes and endothelial cells subjected to 15 minutes of ischaemia was not affected by the treatment of the fixative. However, when the tissue subjected to longer periods of ischaemia was fixed with routinely prepared or oxygen-bubbled glutaraldehyde, ultrastructural changes characteristic of reoxygenation damage were uniformly evident in both the microvasculature and myocytes. These qualitatively distinct changes included mitochondrial swelling, cell swelling, endothelial bleb formation, and narrowing of capillary lumina. These abnormalities were not observed in tissue fixed with nitrogen-bubbled glutaraldehyde. These findings indicate that deliberate steps should be taken to reduce or eliminate dissolved oxygen from the fixatives used to study ischaemic tissues. Otherwise artefactual reoxygenation damage in vitro may occur and make valid ultrastructural interpretation difficult or impossible. 相似文献
6.
7.
Doherty M.F. Bjorklund C.M. Peterson W.K. Collin H.L. 《Geoscience and Remote Sensing, IEEE Transactions on》1993,31(2):407-416
A processing algorithm for automatically detecting a specific type of ion distribution (called the ion conic distribution) in data obtained from a space-based mass spectrometer has been devised. Automation of this task is necessary due to the sparseness of conic events within the very large databases typical of space plasma instruments. The algorithm used to perform this automated analysis and the methods used to verify the algorithm are described. Initial results on the characterization of the near-Earth space plasma are summarized 相似文献
8.
Daniel WinnMichael F. Doherty 《Chemical engineering science》2002,57(10):1805-1813
A method for predicting the shape of organic crystals grown from polar solvents is presented. The model is an improvement of the recent method developed by Winn and Doherty (A.I.Ch.E. Journal 44 (1998) 2501) for predicting the shape of organic crystals grown from solvents in which the energy of adhesion at the interfaces is dominated by dispersive forces (e.g., non-polar solvents). The principal characteristic of the new method is that it can account for the role of hydrogen donor and hydrogen acceptor atoms in forming strong bonds at the interface. This technique is a first step towards predicting the shapes of organic crystals grown from polar solvents, and has been applied successfully to predict the shape of adipic acid grown from water, and succinic acid grown from water and from propanol. 相似文献
9.
10.