全文获取类型
收费全文 | 2961篇 |
免费 | 3篇 |
专业分类
化学工业 | 38篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 12篇 |
能源动力 | 3篇 |
轻工业 | 16篇 |
水利工程 | 1篇 |
石油天然气 | 3篇 |
无线电 | 24篇 |
一般工业技术 | 87篇 |
冶金工业 | 2726篇 |
原子能技术 | 4篇 |
自动化技术 | 47篇 |
出版年
2021年 | 2篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 4篇 |
2013年 | 3篇 |
2012年 | 9篇 |
2011年 | 4篇 |
2010年 | 6篇 |
2009年 | 8篇 |
2008年 | 5篇 |
2007年 | 10篇 |
2006年 | 9篇 |
2005年 | 9篇 |
2004年 | 6篇 |
2003年 | 7篇 |
2002年 | 3篇 |
2001年 | 8篇 |
2000年 | 5篇 |
1999年 | 84篇 |
1998年 | 824篇 |
1997年 | 482篇 |
1996年 | 300篇 |
1995年 | 162篇 |
1994年 | 151篇 |
1993年 | 182篇 |
1992年 | 30篇 |
1991年 | 39篇 |
1990年 | 49篇 |
1989年 | 48篇 |
1988年 | 42篇 |
1987年 | 40篇 |
1986年 | 33篇 |
1985年 | 26篇 |
1984年 | 4篇 |
1983年 | 12篇 |
1982年 | 7篇 |
1981年 | 15篇 |
1980年 | 32篇 |
1979年 | 4篇 |
1978年 | 5篇 |
1977年 | 73篇 |
1976年 | 187篇 |
1975年 | 6篇 |
1972年 | 3篇 |
1969年 | 2篇 |
1956年 | 2篇 |
1955年 | 2篇 |
1943年 | 1篇 |
排序方式: 共有2964条查询结果,搜索用时 46 毫秒
41.
42.
43.
EM Prvulovich JB Bomanji WA Waddington P Rudrasingham AM Verbruggen PJ Ell 《Canadian Metallurgical Quarterly》1997,38(5):809-814
1. Effects of feeding condition from birth were examined on the sensitivity of neuromuscular transmission to d-tubocurarine (dTc) in vitro in male mice of the ddY strain. 2. Mice were trained to climb two separated cylindrical steel-wire tubes for feeding and drinking, respectively, from 16 days of age. Some mice were conventionally fed, from 99 days of age. Nerve-muscle preparations were made from the left phrenic nerve diaphragm muscle (DPH), the sciatic nerve soleus muscle (SOL), and the sciatic nerve extensor digitorum longus muscle (EDL) of 99-day-old and 155-day-old mice. The nerve trunk was electrically activated with trains of four pulses and tetanic pulses. 3. The sensitivity to the effects of dTc decreased in the order EDL, SOL, and DPH. This result held true in all mice tested. 4. This sensitivity was significantly potentiated by the compulsory movement. 5. The supersensitivity remained even when mice were conventionally fed after 99 days of age. 6. The compulsion rendered EDL antifatigable on tetanic stimulation. This property was also retained after a return to conventional feeding. 7. These results suggest that the effects of feeding condition from birth might remain on neuromuscular functions after termination of the conditioning. 相似文献
44.
Peel strengths at room temperature and under superplastic forming conditions at 530 °C were measured for diffusion-bonded joints in Al-Li 8090 alloy sheet. The bonds were made in the solid state, or via a transient liquid phase using interlayers. The effect of strain rate, sheet thickness and heat treatment were investigated. The significance of these results for the testing of DB joints and for their use in DB/SPF structures is discussed. 相似文献
45.
JB Kornfeld 《Canadian Metallurgical Quarterly》1997,32(6):45-6, 51-2
46.
47.
48.
49.
50.
BBN has an illustrious history of contributions to data networking, and has made repeated contributions in the development of networking protocols, network operations, router design, and wireless and satellite networks. Because so much of BBN's early Arpanet work has been documented elsewhere, this history focuses on post-Arpanet contributions that led to the Internet. Arpanet was a continuing source of inspiration, frustration, and innovation, both as a stand-alone network and then as the core of the Internet. 相似文献