全文获取类型
收费全文 | 6675篇 |
免费 | 78篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 36篇 |
综合类 | 4篇 |
化学工业 | 686篇 |
金属工艺 | 83篇 |
机械仪表 | 51篇 |
建筑科学 | 189篇 |
矿业工程 | 12篇 |
能源动力 | 134篇 |
轻工业 | 352篇 |
水利工程 | 24篇 |
石油天然气 | 9篇 |
无线电 | 315篇 |
一般工业技术 | 497篇 |
冶金工业 | 3930篇 |
原子能技术 | 36篇 |
自动化技术 | 399篇 |
出版年
2020年 | 24篇 |
2019年 | 36篇 |
2018年 | 30篇 |
2017年 | 41篇 |
2016年 | 50篇 |
2015年 | 38篇 |
2014年 | 47篇 |
2013年 | 175篇 |
2012年 | 95篇 |
2011年 | 132篇 |
2010年 | 107篇 |
2009年 | 111篇 |
2008年 | 122篇 |
2007年 | 115篇 |
2006年 | 105篇 |
2005年 | 120篇 |
2004年 | 93篇 |
2003年 | 93篇 |
2002年 | 99篇 |
2001年 | 65篇 |
2000年 | 72篇 |
1999年 | 163篇 |
1998年 | 1117篇 |
1997年 | 657篇 |
1996年 | 438篇 |
1995年 | 273篇 |
1994年 | 242篇 |
1993年 | 233篇 |
1992年 | 74篇 |
1991年 | 97篇 |
1990年 | 90篇 |
1989年 | 83篇 |
1988年 | 87篇 |
1987年 | 84篇 |
1986年 | 91篇 |
1985年 | 83篇 |
1984年 | 71篇 |
1983年 | 52篇 |
1982年 | 64篇 |
1981年 | 81篇 |
1980年 | 67篇 |
1979年 | 44篇 |
1978年 | 37篇 |
1977年 | 125篇 |
1976年 | 215篇 |
1975年 | 66篇 |
1974年 | 33篇 |
1973年 | 42篇 |
1972年 | 42篇 |
1970年 | 32篇 |
排序方式: 共有6757条查询结果,搜索用时 156 毫秒
1.
2.
3.
4.
Removal of gold from basic solutions containing [Au(CN)2]? has been demonstrated using the inherently conducting polymer polypyrrole. Polymers containing sulfonated aromatic dopants have been found to display a significant ability to remove gold from such solutions. Experiments performed in solutions containing both gold and copper cyanide complexes indicate that the recovery process is not highly selective. However, the polypyrroles used display significantly faster rates of gold recovery than activated carbon. © 2003 Society of Chemical Industry 相似文献
5.
A semiconductor laser rate equation theory is presented that describes sideband injection locking under both weak optical injection and current modulation. By simultaneous optical injection and current modulation, control of both the phase and the frequency of a semiconductor laser is demonstrated. The phase-locked semiconductor laser operates at a different frequency to the optical injection source, with a frequency-difference given by the current modulation frequency. This method can be used to produce broadband sources, such as those producing ultrashort pulses and those required for coherent control, or to create high-frequency electronic oscillator sources with phase control by interference beating 相似文献
6.
FJ Overdyk PM Gramling-Babb JR Handy NI Faller MJ Miller 《Canadian Metallurgical Quarterly》1997,84(1):213-215
Robertsonian translocations, although relatively common as a constitutional genetic aberration, are rarely encountered in leukaemia. We report a case of acute myeloid leukaemia which showed an acquired Robertsonian translocation in the form of der(14;21) by cytogenetic analysis of leukaemic cells. This was confirmed by the PHA-stimulated culture of peripheral blood lymphocytes. A review of the literature identifies only eight reported cases of acquired Robertsonian translocations in leukaemia. In the majority of cases the Robertsonian translocation occurs as a secondary change in a complex abnormal clone, whereas in two out of nine patients reported, including ours, it is found as a sole karyotypic abnormality. 相似文献
7.
John C. Hart Gordon W. Lescinsky Daniel J. Sandin Thomas A. DeFanti Louis H. Kauffman 《The Visual computer》1993,9(7):346-355
The pipelined architecture and parallel organization of the AT&T Pixel Machine image computer are described and demonstrated with applications for the visualization of multidimensional fractals, particularly linear fractals and quaternion/ stacked Julia sets. Techniques for pushing the Pixel Machine to its peak abilities are described and apply to more recent parallel image computers as well. 相似文献
8.
Twenty-six patients with an intracardiac myxoma underwent surgical resection at our institution from 1977 through 1992. Left atrial myxoma was diagnosed in 22 patients, left ventricular in 1, right atrial in 2, and right ventricular in 1. Six patients were asymptomatic; preoperative symptoms included dyspnea, arrhythmias, embolic episodes, and syncope. The diagnosis was established with transthoracic echocardiography in all cases but one. Surgery was performed in all cases with the aid of cardiopulmonary bypass with moderate hypothermia and cold crystalloid cardioplegia. One patient with a left ventricular myxoma died in a comatose state during the immediate postoperative period. Long-term clinical and echocardiographic evaluation was performed in 19 patients; results were excellent (all the patients were in New York Heart Association functional class I or II), and no recurrences were documented. The clinical characteristics, diagnostic methods, and surgical approach are presented and discussed. 相似文献
9.
10.