全文获取类型
收费全文 | 1064篇 |
免费 | 3篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 18篇 |
化学工业 | 46篇 |
金属工艺 | 7篇 |
机械仪表 | 2篇 |
建筑科学 | 3篇 |
能源动力 | 4篇 |
轻工业 | 19篇 |
水利工程 | 1篇 |
无线电 | 53篇 |
一般工业技术 | 45篇 |
冶金工业 | 861篇 |
原子能技术 | 1篇 |
自动化技术 | 11篇 |
出版年
2022年 | 2篇 |
2021年 | 4篇 |
2020年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 5篇 |
2016年 | 2篇 |
2015年 | 2篇 |
2014年 | 6篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 9篇 |
2010年 | 12篇 |
2009年 | 7篇 |
2008年 | 14篇 |
2007年 | 12篇 |
2006年 | 6篇 |
2005年 | 9篇 |
2004年 | 7篇 |
2003年 | 19篇 |
2002年 | 5篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 27篇 |
1998年 | 263篇 |
1997年 | 172篇 |
1996年 | 117篇 |
1995年 | 53篇 |
1994年 | 47篇 |
1993年 | 40篇 |
1992年 | 9篇 |
1991年 | 12篇 |
1990年 | 11篇 |
1989年 | 13篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 8篇 |
1984年 | 2篇 |
1983年 | 3篇 |
1982年 | 8篇 |
1981年 | 7篇 |
1980年 | 11篇 |
1978年 | 5篇 |
1977年 | 29篇 |
1976年 | 58篇 |
1975年 | 2篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1955年 | 1篇 |
排序方式: 共有1071条查询结果,搜索用时 15 毫秒
51.
The role of prostacyclin and thromboxane A2 in the pathogenesis of Bartter's syndrome was investigated by measurement of the urinary excretion of 6-keto-PGF1 alpha and thromboxane B2, respectively, in five patients. The prostaglandin metabolites were extracted from urine by a reproducible method and measured by specific radioimmunoassays. The patients with Bartter's syndrome excreted about four-times as much 6-keto-PGF1 alpha as the normal controls. In contrast, there was no significant difference in the urinary excretion of thromboxane B2 between the patients and the controls. In a second part of the study, three patients were treated with indomethacin (150 mg/day for four days), an inhibitor of prostaglandin synthesis. This regimen suppressed urinary excretion of 6-keto-PGF1 alpha by 43% and that of thromboxane B2 by 46%. It is suggested that the increase in prostacyclin production is responsible for both the hyperreninemia and and the other endocrine derangements as well as the hyporesponsiveness of blood pressure to intravenous infusion of vasopressors in patients with Bartter's syndrome. 相似文献
52.
53.
54.
55.
56.
Composite metacarpophalangeal joint reconstruction using the toe proximal phalanx and the metacarpal head, with a capsular repair, is an option during free toe transfer procedures for absent fingers. Eleven composite metacarpophalangeal finger joint reconstructions were performed in four patients concurrent with combined second and third toe-to-hand transfer. The average follow-up period was 5 years. Postoperative assessment included range of motion, stability, radiographic changes, and pain. The average range of motion was 52 degrees, average ulnar stress deviation was 14 degrees. No patients complained of pain. Composite metacarpophalangeal joint reconstruction should be considered in free toe-to-hand procedures when metacarpal head articular cartilage is preserved. 相似文献
57.
Toshiyuki Sawa Yasuo Sato Mitsuo Tsurugai Tsukasa Onishi 《Electrical Engineering in Japan》2011,175(1):25-34
We have developed an innovative power generation scheduling method using quadratic programming (QP). The advantage of using our method is that it simultaneously solves unit commitment and economic load dispatch. We relax the binary variables of the unit state into continuous variables to apply QP to this problem. We also add a penalty term to converge the value of those variables to 0 or 1 to the objective function: the sum of the fuel costs and the start‐up costs. This penalty term depends on the per‐unit fuel cost. The possibility of its variable converging to zero increases as the cost increases. This method was applied to a test system of daily generation scheduling that consisted of 29 thermal units, two pumped‐storage units, four cascaded hydro units, and one transmission. The schedule satisfied all constraints, that is, load‐power balance, operation reserve, power flow, minimum up/down‐times, and fuel consumption. This result shows that the proposed method is effective. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 175(1): 25–34, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21014 相似文献
58.
59.
1,2‐Propanediol–cellulose–acrylamide graft copolymers (PCACs) were developed for enhanced oil recovery. They were prepared with acrylamide and 1,2‐propanediol (PDO)–cellulose, which was formed through the addition of glycols to cellulose by the Shotten–Baumann reaction between 3‐chloro‐1,2‐propanediol and cellulose. The graft copolymerization was initiated with a redox system between Ce4+ and glycols in cellulose. The infrared spectrum of PDO–cellulose had some characteristic absorption bands around 2960 (νC? H) and 1050 cm?1 (νC? O) that also appeared for the PDO group and pyranose ring of cellulose, respectively. The rate of Ce4+ consumption by PDO–cellulose was investigated through the calculation of the overall kinetic constant from the slopes of ln(D ? DR) versus time (where D is the absorbance and DR is the absorbance of the original polysaccharide solution) The results showed that PDO–cellulose had high reactivity and that there were two mechanisms of oxidation by Ce4+ with PDO–cellulose. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 92: 3022–3029, 2004 相似文献
60.