全文获取类型
收费全文 | 3756篇 |
免费 | 3篇 |
专业分类
化学工业 | 10篇 |
轻工业 | 2篇 |
石油天然气 | 2篇 |
无线电 | 4篇 |
一般工业技术 | 3篇 |
冶金工业 | 3734篇 |
自动化技术 | 4篇 |
出版年
2024年 | 1篇 |
2021年 | 1篇 |
2016年 | 2篇 |
2015年 | 1篇 |
2005年 | 1篇 |
2004年 | 4篇 |
2003年 | 7篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 100篇 |
1998年 | 1055篇 |
1997年 | 584篇 |
1996年 | 440篇 |
1995年 | 231篇 |
1994年 | 187篇 |
1993年 | 239篇 |
1992年 | 33篇 |
1991年 | 57篇 |
1990年 | 67篇 |
1989年 | 92篇 |
1988年 | 46篇 |
1987年 | 73篇 |
1986年 | 48篇 |
1985年 | 63篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 21篇 |
1981年 | 16篇 |
1980年 | 35篇 |
1979年 | 2篇 |
1978年 | 7篇 |
1977年 | 88篇 |
1976年 | 237篇 |
1975年 | 7篇 |
1969年 | 1篇 |
1965年 | 1篇 |
1955年 | 3篇 |
排序方式: 共有3759条查询结果,搜索用时 15 毫秒
201.
202.
203.
The degeneration of the substantia nigra that characterises Parkinson's disease may cause an alteration in sensitivity of striatal dopamine receptors. The development of denervation supersensitivity has been held to be responsible for some of the effects of chronic levodopa therapy. The rotating rodent is an animal model commonly used to study the phenomenon of striatal dopamine receptor supersensitivity, and to investigate drugs which may prove to be beneficial in the treatment of Parkinson's disease. We have investigated as to whether long-term oral administration of levodopa to mice with unilateral destruction of striatal dopaminergic nerve terminals influences dopaminergic receptor denervation supersensitivity as judged by the circling response following systemically administered levodopa. It does not do so and the relevance of these findings to the treatment of Parkinson's disease is discussed. 相似文献
204.
205.
DG Lambie JW Paxon RN Nanda RH Johnson JG Ratcliffee ID Melville GD Morrice 《Canadian Metallurgical Quarterly》1976,21(2):93-94
Using Wistar stain male rats, it has been shown that 2 atmospheric pressures associated with oxygen saturation, together or singly for 90 minutes daily for successive 46 days, resulted in no significant change on the ratio of testes to body weight. No significant change was observed in the incorporation of 3H-thymidine into testes and pituitary glands between the pressure-treated groups and the control group. 相似文献
206.
207.
Effects of leukotriene D on the airways in asthma 总被引:2,自引:0,他引:2
M Griffin JW Weiss AG Leitch ER McFadden EJ Corey KF Austen JM Drazen 《Canadian Metallurgical Quarterly》1983,308(8):436-439
208.
We have modified a snare technique originally described for transcolonoscopic removal of colonic polyps for the retrieval of intravascular foreign bodies. The key difference from other snare techniques is the employment of a wire snare with a crimp in its midportion that enables the formation of a loop in a plane perpendicular to the axial direction of the guiding catheter. With this technique we have quickly removed a variety of objects from the right heart and pulmonary arteries in four patients. 相似文献
209.
210.