全文获取类型
收费全文 | 498篇 |
免费 | 16篇 |
专业分类
电工技术 | 12篇 |
综合类 | 1篇 |
化学工业 | 113篇 |
金属工艺 | 13篇 |
机械仪表 | 10篇 |
建筑科学 | 8篇 |
能源动力 | 25篇 |
轻工业 | 17篇 |
水利工程 | 1篇 |
石油天然气 | 2篇 |
无线电 | 56篇 |
一般工业技术 | 86篇 |
冶金工业 | 103篇 |
原子能技术 | 10篇 |
自动化技术 | 57篇 |
出版年
2022年 | 14篇 |
2021年 | 9篇 |
2020年 | 4篇 |
2019年 | 4篇 |
2017年 | 9篇 |
2016年 | 13篇 |
2015年 | 12篇 |
2014年 | 23篇 |
2013年 | 23篇 |
2012年 | 15篇 |
2011年 | 27篇 |
2010年 | 20篇 |
2009年 | 20篇 |
2008年 | 15篇 |
2007年 | 21篇 |
2006年 | 23篇 |
2005年 | 15篇 |
2004年 | 12篇 |
2003年 | 8篇 |
2002年 | 14篇 |
2001年 | 5篇 |
2000年 | 7篇 |
1999年 | 8篇 |
1998年 | 38篇 |
1997年 | 32篇 |
1996年 | 13篇 |
1995年 | 9篇 |
1994年 | 10篇 |
1993年 | 7篇 |
1992年 | 4篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 5篇 |
1987年 | 4篇 |
1986年 | 7篇 |
1985年 | 9篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 3篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 5篇 |
1977年 | 2篇 |
1976年 | 5篇 |
1975年 | 2篇 |
1973年 | 3篇 |
1972年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有514条查询结果,搜索用时 15 毫秒
61.
M Tatsuta H Iishi M Baba H Yano H Uehara A Nakaizumi 《Canadian Metallurgical Quarterly》1996,17(2):293-296
The effects of baclofen, a gamma-amino-n-butyric acid receptor B agonist, on gastric carcinogenesis induced by N-methyl-N'-nitro-N-nitrosoguanidine and how its effects are influenced by selective (M1) and non-selective (M1 and M2) pharmacological blockade of muscarinic receptors were investigated in inbred Wistar rats. Rats were given s.c. injections of 8 mg/kg body wt baclofen with and without 0.5 mg/kg body wt atropine (non-selective M1 and M2 muscarinic receptor antagonist) or 1.0 mg/kg body wt pirenzepine (selective M1 muscarinic receptor antagonist) every other day after a 25 week carcinogen treatment. At week 52 baclofen significantly decreased the incidence of gastric cancers. Concomitant treatment with atropine significantly attenuated the inhibition by baclofen of gastric carcinogenesis, but combined use with pirenzepine had no significant effect on the inhibition by baclofen of gastric carcinogenesis. Baclofen also significantly decreased the labeling index of the antral mucosa. Baclofen plus atropine attenuated the decrease in the labeling index of the antral mucosa due to baclofen, but baclofen plus pirenzepine had no significant effect on the labeling index. These results suggest that the inhibition of gastric carcinogenesis by baclofen is mediated through muscarinic receptors and M2 receptors, but not M1 receptors, are involved in this response. 相似文献
62.
Susumu Onaka Satoshi Soeta Masaharu Kato Ryohei Tanaka 《Journal of Materials Science》1988,23(2):577-582
Bicrystals of CU-SiO2 dispersion-hardened alloys and of pure copper were tensile tested at various temperatures between 450 and 1050 K at a strain rate of 1.5 x 10–4 sec–1. In the case of pure copper bicrystals, elongation to fracture did not depend significantly on temperature and the fracture mode was invariably transgranular up to 850 K. On the other hand, the ductility of CU-SiO2 bicrystals decreased with increase in temperature and the transition in the fracture mode from transgranular to intergranular occurred at around 450 K. SiO2 particles on grain boundaries play an important role on intergranular fracture by suppressing grain-boundary sliding and also on the retardation of recrystallization during deformation. Two types of Cu-SiO2 bicrystals having different crystal orientation relationships show quite different deformation and fracture behaviour. This can be explained in terms of the contribution of lattice dislocations to the grain-boundary sliding. 相似文献
63.
64.
65.
66.
In order to investigate the optimum transmission bit-rate for teletext signals in the 525-line television system, laboratory and field tests were carried out using binary NRZ digital data signals of several bit-rates to 5.73 Mbit/s ( 364fH, 8/5fsc). In these tests, the bit-errors and eye-openings of PN signals were measured and subjective evaluation of teletext signals was also made under various receiving conditions. The results have indicated that a digital data signal of 5.73 Mbit/s could be utilized for teletext in the 525-line television system. The Japanese teletext system now being developed employs this bit-rate for transmitting and displaying the signals. 相似文献
67.
68.
69.
Ethanol and lactic acid production using sap squeezed from old oil palm trunks felled for replanting
Akihiko Kosugi Ryohei Tanaka Kengo Magara Yoshinori Murata Takamitsu Arai Othman Sulaiman Rokiah Hashim Zubaidah Aimi Abdul Hamid Mohd Khairul Azri Yahya Mohd Nor Mohd Yusof Wan Asma Ibrahim Yutaka Mori 《Journal of Bioscience and Bioengineering》2010,110(3):322-325
Old oil palm trunks that had been felled for replanting were found to contain large quantities of high glucose content sap. Notably, the sap in the inner part of the trunk accounted for more than 80% of the whole trunk weight. The glucose concentration of the sap from the inner part was 85.2 g/L and decreased towards the outer part. Other sugars found in relatively low concentrations were sucrose, fructose, galactose, xylose, and rhamnose. In addition, oil palm sap was found to be rich in various kinds of amino acids, organic acids, minerals and vitamins. Based on these findings, we fermented the sap to produce ethanol using the sake brewing yeast strain, Saccharomyces cerevisiae Kyokai no.7. Ethanol was produced from the sap without the addition of nutrients, at a comparable rate and yield to the reference fermentation on YPD medium with glucose as a carbon source. Likewise, we produced lactic acid, a promising material for bio-plastics, poly-lactate, from the sap using the homolactic acid bacterium Lactobacillus lactis ATCC19435. We confirmed that sugars contained in the sap were readily converted to lactic acid with almost the same efficiency as the reference fermentation on MSR medium with glucose as a substrate. These results indicate that oil palm trunks felled for replanting are a significant resource for the production of fuel ethanol and lactic acid in palm oil-producing countries such as Malaysia and Indonesia. 相似文献
70.
Go Kagiya Ryohei Ogawa John A. Cook Rajani Choudhuri Masanori Hatashita Yoshikazu Tanaka Bill G. DeGraff James B. Mitchell 《Journal of Bioscience and Bioengineering》2010,110(1):118-123
A promoter that augments gene expression in response to stimulation of ionizing radiation would be a desired tool for radiogenetic therapy, a combination of radiotherapy and gene therapy. Although various promoters occurring naturally or artificially have been used for researches, one showing higher reactivity to ionizing radiation is desirable. In the present study, we attempted to improve a radiation-responsive promoter of the p21 through a technique called DNA shuffling. A library of DNA fragments was constructed by re-ligation of randomly digested promoter fragments and improved promoters were chosen out of the library. We repeated this process twice to obtain a promoter showing 2.6-fold better reactivity to ionizing radiation compared with its parent, p21 promoter after 10 Gy γ-ray irradiation. Nucleotide sequence analyses revealed that the obtained promoter was densely packed with some of the cis-acting elements including binding sites for p53, NF-κB, NRF-2, AP-1 and NF-Y more than p21 promoter. In addition, it was shown that its induction by ionizing radiation was dependent upon p53 status of a cell line, suggesting that the promoter retained properties of the p21 promoter. This technique is simple and efficient to improve a promoter responsive to other stimulus of interest besides IR. 相似文献