全文获取类型
收费全文 | 100944篇 |
免费 | 10958篇 |
国内免费 | 6505篇 |
专业分类
电工技术 | 7902篇 |
技术理论 | 7篇 |
综合类 | 8385篇 |
化学工业 | 14585篇 |
金属工艺 | 5504篇 |
机械仪表 | 6633篇 |
建筑科学 | 8294篇 |
矿业工程 | 3209篇 |
能源动力 | 2795篇 |
轻工业 | 8613篇 |
水利工程 | 2426篇 |
石油天然气 | 4672篇 |
武器工业 | 1154篇 |
无线电 | 12511篇 |
一般工业技术 | 10168篇 |
冶金工业 | 3871篇 |
原子能技术 | 1347篇 |
自动化技术 | 16331篇 |
出版年
2024年 | 595篇 |
2023年 | 1809篇 |
2022年 | 3709篇 |
2021年 | 5098篇 |
2020年 | 3877篇 |
2019年 | 2902篇 |
2018年 | 3291篇 |
2017年 | 3666篇 |
2016年 | 3232篇 |
2015年 | 4880篇 |
2014年 | 6212篇 |
2013年 | 7141篇 |
2012年 | 8441篇 |
2011年 | 8764篇 |
2010年 | 7978篇 |
2009年 | 7370篇 |
2008年 | 7158篇 |
2007年 | 6527篇 |
2006年 | 5589篇 |
2005年 | 4568篇 |
2004年 | 3094篇 |
2003年 | 2176篇 |
2002年 | 2072篇 |
2001年 | 1618篇 |
2000年 | 1376篇 |
1999年 | 1153篇 |
1998年 | 796篇 |
1997年 | 643篇 |
1996年 | 550篇 |
1995年 | 481篇 |
1994年 | 375篇 |
1993年 | 283篇 |
1992年 | 201篇 |
1991年 | 185篇 |
1990年 | 133篇 |
1989年 | 106篇 |
1988年 | 82篇 |
1987年 | 52篇 |
1986年 | 37篇 |
1985年 | 21篇 |
1984年 | 15篇 |
1982年 | 14篇 |
1981年 | 16篇 |
1980年 | 27篇 |
1979年 | 19篇 |
1976年 | 9篇 |
1974年 | 5篇 |
1973年 | 5篇 |
1959年 | 15篇 |
1951年 | 15篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
32.
33.
34.
为了保证广角摄像机在现代机器人视觉定位应用中的准确性,以广角摄像机像素坐标的反畸变过程为研究对象,提出一种在畸变对应表的基础上使用中心迭代法以及区域插值法确定物体实际位置的方法。通过实验证明了该方法能够测量物体的位置,其精度能够满足工业使用要求。 相似文献
36.
Donggang Yao Pratapkumar Nagarajan Lei Li Allen Y. Yi 《Polymer Engineering and Science》2007,47(4):530-539
An embossing strategy involving a hot station and a cold station for sequentially heating and cooling the embossing tool was investigated to reduce cycle times in hot embossing polymer microstructures. Experimental studies showed that aluminum stamps with a thickness of 1.4 mm can be rapidly heated from room temperature to 200°C in 3 s using contact heating against a hot station at 250°C. Microchannels and microlenses were successfully embossed onto high‐density polyethylene and acrylonitrile–butadiene–styrene substrates using a heating time less than 3 s and a total cycle time around 10 s. The two‐station embossing process for the microlens was also numerically studied. The simulated filling behavior agreed with the experimental observation and the predicted thermal and deformation history of the polymer offered a good explanation on the experimentally observed process characteristics. POLYM. ENG. SCI., 47:530–539, 2007. © 2007 Society of Plastics Engineers. 相似文献
37.
38.
NISHI Michihiro 《中国科学:信息科学(英文版)》2010,(1)
A novel double suction shaft-less mini pump was developed for heat control of small energy systems in this study.The mini pump impeller with an exit diameter of 40 mm was combined with the motor rotor supported by the hybrid dynamic bearing.The specific speed of the pump was 125 min-1 m3 min-1 m.The hydraulic performance of the pump was investigated experimen-tally under four rotational speeds.From the test results,it was recognized that the pump could provide a flow discharge of 5 L/min and head of 1.5 m,w... 相似文献
39.
40.
Concrete structures in main coal cleaning plants have been rebuilt and reinforced in the coal mines of the Shanghai Da-tun Energy Sources Co. Ltd., the first colliery of the Pingdingshan Coal Co. Ltd. and the Sanhejian mine of the Xuzhou Mining Group Co. Ltd. In these projects, the operating environment and reliability of concrete structures in the main plants of the three companies were investigated and the safety of the structures inspected. Qualitative and quantitative analyses were made on the spe-cial natural, technological and mechanical environments around the structures. On the basis of these analyses, we discuss the long-term, combined actions of the harsh natural (corrosive gases, liquids and solids) and mechanical environments on concrete structures and further investigated the damage and deteriorating mechanisms and curing techniques of concrete structures in the main coal cleaning plants. Our study can provide a theoretical basis for ensuring the reliability of concrete structures in main coal cleaning plants. 相似文献