全文获取类型
收费全文 | 11382篇 |
免费 | 702篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 162篇 |
综合类 | 42篇 |
化学工业 | 2195篇 |
金属工艺 | 320篇 |
机械仪表 | 241篇 |
建筑科学 | 596篇 |
矿业工程 | 56篇 |
能源动力 | 140篇 |
轻工业 | 1710篇 |
水利工程 | 79篇 |
石油天然气 | 14篇 |
无线电 | 759篇 |
一般工业技术 | 2854篇 |
冶金工业 | 1348篇 |
原子能技术 | 89篇 |
自动化技术 | 1481篇 |
出版年
2023年 | 131篇 |
2022年 | 77篇 |
2021年 | 209篇 |
2020年 | 168篇 |
2019年 | 161篇 |
2018年 | 348篇 |
2017年 | 367篇 |
2016年 | 406篇 |
2015年 | 309篇 |
2014年 | 393篇 |
2013年 | 696篇 |
2012年 | 527篇 |
2011年 | 623篇 |
2010年 | 490篇 |
2009年 | 488篇 |
2008年 | 571篇 |
2007年 | 505篇 |
2006年 | 396篇 |
2005年 | 311篇 |
2004年 | 270篇 |
2003年 | 268篇 |
2002年 | 244篇 |
2001年 | 225篇 |
2000年 | 174篇 |
1999年 | 177篇 |
1998年 | 469篇 |
1997年 | 296篇 |
1996年 | 258篇 |
1995年 | 158篇 |
1994年 | 161篇 |
1993年 | 136篇 |
1992年 | 67篇 |
1991年 | 88篇 |
1990年 | 54篇 |
1989年 | 87篇 |
1988年 | 50篇 |
1987年 | 70篇 |
1986年 | 82篇 |
1985年 | 131篇 |
1984年 | 88篇 |
1983年 | 76篇 |
1982年 | 79篇 |
1981年 | 59篇 |
1980年 | 59篇 |
1979年 | 59篇 |
1978年 | 55篇 |
1977年 | 54篇 |
1976年 | 104篇 |
1975年 | 42篇 |
1973年 | 44篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
82.
Wan-Yu Wu Jyh-Ming Ting Hayo Zutz Dominika Lyzwa Inga Gerhards Carsten Ronning Hans Hofsäss 《Diamond and Related Materials》2008,17(7-10):1494-1497
While experimenting with the growth of metal-containing amorphous carbon (a-c:Me) thin films using two different growth processes, self-assembled multilayered structures were observed. One of the processes is a reactive magnetron sputter deposition process. The other process is a mass selective ion beam deposition process. Despite of the differences in the growth method and the growth condition, self-assembled multilayered thin films, consisting of alternating dark layer and bright layer, were obtained in both processes. Based on the consideration of energy for atomic diffusion in the thin films, the growth mechanism is discussed. 相似文献
83.
84.
85.
86.
M Kester RJ Nowinski H Holth?fer PA Marsden MJ Dunn 《Canadian Metallurgical Quarterly》1994,46(5):1404-1412
Platelet-activating factor synthesis in two transformed lines of glomerular endothelial cells was characterized and contrasted with platelet-activating factor production in macrovascular-derived endothelial cells as well as with glomerular cells of mesenchymal origin. Platelet-activating factor synthesis was assessed in intact cells and in cell-free preparations. Glomerular endothelial cells constitutively synthesize bio-active alkyl-PAF, and this basal activity can be chronically augmented by various inflammatory and thrombotic agents. In contrast, thrombin-mediated platelet-activating factor formation in bovine pulmonary aortic endothelial cells as well as in glomerular mesangial cells is acute and transient. The potential role of anti-inflammatory prostanoids to function as negative feedback modulators of thrombin- or endothelin-mediated platelet-activating factor synthesis was also investigated, as the synthesis of platelet-activating factor is often associated with the formation of these prostanoids. Indomethacin augmented receptor-mediated platelet-activating factor synthesis while prostanoids of the E and I series reduced agonist-stimulated PAF synthesis. In summary, the unique capacity of glomerular endothelial cells to respond to inflammatory stimuli with sustained platelet-activating factor synthesis is a clear indication of this cell's pivotal role in augmenting the inflammatory response in the limited environment of the glomerulus. 相似文献
87.
88.
89.
90.
S. Salar Behzadi Silvester Ölzant Reinhard Länger Christian Koban Frank M. Unger Helmut Viernstein 《European Food Research and Technology》2006,223(2):238-245
Inversion of sucrose is a stability problem particularly of candies with acidic taste that contain sucrose and small amounts of organic acids such as citric acid, since the free d-fructose produced by hydrolysis is hygroscopic. The following possibilities were investigated for preventing the hydrolysis of sucrose in tablets containing sucrose and citric acid: Adding various amounts of tri-sodium citrate to the formulation to neutralize the citric acid, (Hot) melt coating of citric acid and tri-sodium citrate with a vegetable fat at different coating ratios, variation of the ratio of coated citric acid and tri-sodium citrate in formulations, and compressing the formulations with different compression forces. After tablet processing and storage of tablets, the concentration of d-fructose was determined on the basis of enzymatic reactions. A response surface central composite design was used. The above-mentioned variations were chosen as independent variables and the amount of d-fructose was chosen as response variable. The lowest rates of inversion could be achieved by increasing the content of tri-sodium citrate and the ratio of coating material and decreasing the ratio of coated citric acid and tri-sodium citrate in the tablet formulations. The compression force had no significant effect on the inversion of sucrose. 相似文献