全文获取类型
收费全文 | 6491篇 |
免费 | 2篇 |
专业分类
电工技术 | 2篇 |
化学工业 | 13篇 |
建筑科学 | 2篇 |
轻工业 | 4篇 |
水利工程 | 1篇 |
石油天然气 | 1篇 |
无线电 | 4篇 |
一般工业技术 | 3篇 |
冶金工业 | 6454篇 |
自动化技术 | 9篇 |
出版年
2023年 | 1篇 |
2019年 | 2篇 |
2015年 | 1篇 |
2014年 | 1篇 |
2007年 | 2篇 |
2006年 | 1篇 |
2005年 | 2篇 |
2003年 | 9篇 |
2001年 | 3篇 |
2000年 | 3篇 |
1999年 | 158篇 |
1998年 | 1920篇 |
1997年 | 1132篇 |
1996年 | 755篇 |
1995年 | 386篇 |
1994年 | 344篇 |
1993年 | 386篇 |
1992年 | 49篇 |
1991年 | 101篇 |
1990年 | 104篇 |
1989年 | 89篇 |
1988年 | 101篇 |
1987年 | 87篇 |
1986年 | 76篇 |
1985年 | 59篇 |
1983年 | 12篇 |
1982年 | 32篇 |
1981年 | 47篇 |
1980年 | 57篇 |
1978年 | 26篇 |
1977年 | 180篇 |
1976年 | 350篇 |
1975年 | 10篇 |
1955年 | 4篇 |
1954年 | 3篇 |
排序方式: 共有6493条查询结果,搜索用时 11 毫秒
81.
JP Davidson 《Canadian Metallurgical Quarterly》1976,(27):VIII3-VIII15
An area detector for thermal neutrons based on image intensification techniques has been described. Some capabilities and limitations of the detection system have been discussed. Among the former are high spatial resolution, high instantaneous counting rate, electronic zoom, time-gating, and integration. The detector is limited in that the maximum counting rate for a resolution element is 60 regularly spaced counts per second. Also, the nonuniformity of response over the detector puts a limit on the useful size and necessitates point-by-point calibration. In addition, a higher efficiency for neutron detection would be desirable. Some typical applications of the system are crystal inspection, neutron magnetic diffraction topography, and searches for temperature-induced changes in diffraction patterns. The future application of solid-state television sensors and microchannel-plate intensifiers to improve the system were briefly mentioned. 相似文献
82.
83.
84.
85.
86.
87.
JP Miguet C Monange JP Carbillet F Bernard G Pageaut G Camelot M Gillet P Carayon H Gisselbrecht 《Canadian Metallurgical Quarterly》1976,65(1):23-32
A three-factor factorial experiment was performed to assess the efficiency of lipid extraction from the back of human volunteers. Chloroform-methanol (2:1 v/v) proved substantially superior to acetone or diethyl ether. The latter two solvents were also significantly more efficient than n-hexane. The implication of the findings is discussed with regard to the isolation and characterization of fungistatic and bacteriostatic agents on the surface of the skin. 相似文献
88.
89.
90.