全文获取类型
收费全文 | 5356篇 |
免费 | 83篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 66篇 |
综合类 | 13篇 |
化学工业 | 476篇 |
金属工艺 | 62篇 |
机械仪表 | 55篇 |
建筑科学 | 350篇 |
矿业工程 | 2篇 |
能源动力 | 99篇 |
轻工业 | 525篇 |
水利工程 | 28篇 |
石油天然气 | 3篇 |
无线电 | 227篇 |
一般工业技术 | 457篇 |
冶金工业 | 2660篇 |
原子能技术 | 54篇 |
自动化技术 | 363篇 |
出版年
2022年 | 34篇 |
2021年 | 67篇 |
2020年 | 28篇 |
2019年 | 38篇 |
2018年 | 53篇 |
2017年 | 45篇 |
2016年 | 61篇 |
2015年 | 50篇 |
2014年 | 66篇 |
2013年 | 95篇 |
2012年 | 121篇 |
2011年 | 172篇 |
2010年 | 121篇 |
2009年 | 113篇 |
2008年 | 127篇 |
2007年 | 271篇 |
2006年 | 87篇 |
2005年 | 88篇 |
2004年 | 83篇 |
2003年 | 90篇 |
2002年 | 79篇 |
2001年 | 61篇 |
2000年 | 71篇 |
1999年 | 122篇 |
1998年 | 846篇 |
1997年 | 500篇 |
1996年 | 319篇 |
1995年 | 205篇 |
1994年 | 155篇 |
1993年 | 167篇 |
1992年 | 42篇 |
1991年 | 65篇 |
1990年 | 59篇 |
1989年 | 57篇 |
1988年 | 45篇 |
1987年 | 55篇 |
1986年 | 41篇 |
1985年 | 47篇 |
1984年 | 25篇 |
1983年 | 19篇 |
1982年 | 28篇 |
1981年 | 45篇 |
1980年 | 38篇 |
1979年 | 38篇 |
1978年 | 20篇 |
1977年 | 60篇 |
1976年 | 128篇 |
1975年 | 17篇 |
1974年 | 17篇 |
1973年 | 24篇 |
排序方式: 共有5440条查询结果,搜索用时 0 毫秒
31.
Summary ESCA is used to characterize ion beam irradiated P(p-ClPhMA)-samples. The results show a chlorine abstraction. The experimental
findings are in accordance with a recently proposed model for a crosslinking mechanism of halogenated aromatic polymers. 相似文献
32.
Cho Younghee; Luce R. Duncan; von Winterfeldt Detlof 《Canadian Metallurgical Quarterly》1994,20(5):931
A rank- and sign-dependent utility theory is based on an operation of joint receipt of 2 independent gambles and 3 assumptions regarding the operation (R. D. Luce, 1992). The authors tested these 3 assumptions (i.e., segregation, duplex decomposition, and the additivity of certainty equivalents over joint receipt) using both judged and choice certainty equivalents (CEs). Median choice CEs provided support for both segregation and duplex decomposition but little support for additivity in gains or in losses, whereas median judged CEs also failed to support segregation. The latter failure appears to result from some Ss misunderstanding the instructions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
33.
34.
SB Guze 《Canadian Metallurgical Quarterly》1993,181(10):593-594
35.
36.
Cell recognition, signal induction, and symmetrical gene activation at the dorsal-ventral boundary of the developing Drosophila wing 总被引:2,自引:0,他引:2
Appendage formation in insects and vertebrates depends upon signals from both the anterior-posterior and dorsal-ventral (DV) axes. In Drosophila, wing formation is organized symmetrically around the DV boundary of the growing wing imaginal disc and requires interactions between dorsal and ventral cells. Compartmentalization of the wing disc, dorsal cell behavior, and the expression of two dorsally expressed putative signaling molecules, fringe (fng) and Serrate (Ser), are regulated by the apterous selector gene. Here, we demonstrate that fng and Ser have distinct roles in a novel cell recognition and signal induction process. fng serves as a boundary-determining molecule such that Ser is induced wherever cells expressing fng and cells not expressing fng are juxtaposed. Ser in turn triggers the expression of genes involved in wing growth and patterning on both sides of the DV boundary. 相似文献
37.
38.
I. Sevostianov N. K. Sookay C. J. von Klemperer V. E. Verijenko 《Composite Structures》2003,62(3-4):417-421
Attempts to model the degradation of polymer composites have been restricted to modelling the effects of selected degradation mechanisms. No comprehensive model has yet been accepted to predict the effect of the natural environment on the strength of polymer composites. From a review of available literature, it appears that the matrix of a polymer composite is most affected by exposure to the natural environment. Further, the damage appears to progress from the surface into the interior of the laminate. An approach has been developed to determine the properties of the damaged layer and combine the properties of the damaged and undamaged layer to obtain bulk material properties of the laminate. 相似文献
39.
40.