全文获取类型
收费全文 | 2879篇 |
免费 | 492篇 |
国内免费 | 220篇 |
专业分类
电工技术 | 298篇 |
综合类 | 407篇 |
化学工业 | 179篇 |
金属工艺 | 124篇 |
机械仪表 | 407篇 |
建筑科学 | 102篇 |
矿业工程 | 77篇 |
能源动力 | 107篇 |
轻工业 | 102篇 |
水利工程 | 159篇 |
石油天然气 | 42篇 |
武器工业 | 39篇 |
无线电 | 534篇 |
一般工业技术 | 265篇 |
冶金工业 | 64篇 |
原子能技术 | 26篇 |
自动化技术 | 659篇 |
出版年
2024年 | 28篇 |
2023年 | 83篇 |
2022年 | 123篇 |
2021年 | 133篇 |
2020年 | 159篇 |
2019年 | 139篇 |
2018年 | 120篇 |
2017年 | 140篇 |
2016年 | 123篇 |
2015年 | 123篇 |
2014年 | 176篇 |
2013年 | 163篇 |
2012年 | 222篇 |
2011年 | 245篇 |
2010年 | 162篇 |
2009年 | 182篇 |
2008年 | 138篇 |
2007年 | 161篇 |
2006年 | 166篇 |
2005年 | 124篇 |
2004年 | 102篇 |
2003年 | 89篇 |
2002年 | 67篇 |
2001年 | 60篇 |
2000年 | 75篇 |
1999年 | 42篇 |
1998年 | 36篇 |
1997年 | 33篇 |
1996年 | 41篇 |
1995年 | 33篇 |
1994年 | 20篇 |
1993年 | 12篇 |
1992年 | 12篇 |
1991年 | 13篇 |
1990年 | 6篇 |
1989年 | 6篇 |
1988年 | 11篇 |
1987年 | 3篇 |
1986年 | 8篇 |
1985年 | 5篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1979年 | 1篇 |
1975年 | 1篇 |
1964年 | 1篇 |
排序方式: 共有3591条查询结果,搜索用时 0 毫秒
101.
针对实测的元胞负荷数据中存在随机波动现象而使空间负荷预测精度降低的问题,提出一种利用互补集合经验模态分解(CEEMD)和游程检验技术确定元胞负荷合理最大值的方法。该方法通过互补集合经验模态分解技术将各Ⅰ类元胞负荷序列分别进行分解,每个Ⅰ类元胞得到一组本征模态函数,采用游程检验技术对每个本征模态函数进行随机性检验,建立识别其中高频分量的判据,剔除刻画元胞负荷随机波动性的高频本征模态函数,对余下表征元胞负荷规律性与趋势性的本征模态函数进行重构得到主体分量,将其中最大值作为Ⅰ类元胞负荷合理最大值,最后利用该合理最大值进行基于Ⅰ类元胞和Ⅱ类元胞的空间负荷预测。工程实例表明了该方法正确有效。 相似文献
102.
103.
LUBRICATION FILM FORMATION MECHANISM OF SLIPPER PAIRS IN LOW SPEED HIGH TORQUE HYDRAULIC MOTORS 总被引:2,自引:0,他引:2
LI Yong SHI Guanglin CHEN Zhaoneng Research Institute of Mechatronics Shanghai Jiaotong University Shanghai China 《机械工程学报(英文版)》2007,20(1):31-35
Pressure-flow analytical formulas of lubrication film of slipper pairs on camshaft connect- ing rod type low speed high torque (LSHT) hydraulic motors are put forward. The bottom surface of slipper pairs is rectangle, and the effect of squeeze flow and pressure differential flow is considered. The dynamic process of lubrication film formation through squeezing is numerically studied by com- puter simulation. Effects of supply pressure, initial lubrication film thickness, velocity damping coef- ficient, loading impact and gravity, etc are studied. Advantages of novel slipper pairs with large oil cavity area are pointed out. 相似文献
104.
105.
利用0.35μm工艺条件实现了性能优良的小尺寸全耗尽的器件硅绝缘体技术(SOI)互补金属氧化物半导体(FD SOI CMOS)器件,器件制作采用双多晶硅栅工艺、低掺杂浓度源/漏(LDD)结构以及突起的源漏区。这种结构的器件防止漏的击穿,减小短沟道效应(SCE)和漏感应势垒降低效应(DIBL);突起的源漏区增加了源漏区的厚度并减小源漏区的串联电阻,增强了器件的电流驱动能力。设计了101级环形振荡器电路,并对该电路进行测试与分析。根据在3V工作电压下环形振荡器电路的振荡波形图,计算出其单级门延迟时间为45ps,远小于体硅CMOS的单级门延迟时间。 相似文献
106.
不对称数字用户线(ADSL) 总被引:8,自引:3,他引:8
本文对不对称数字用户线(ADSL)的基本概念,所能提供的宽带业务、技术性能、系统组成作了和说明,并指出利用ADSL,把宽带信息沿普通电话线(铜线)送到千家万户,是数十年时间内过渡到光纤到家(FTTH)的有效传输手段。 相似文献
107.
108.
《Digital Communications & Networks》2023,9(1):3-13
There are many problems in Social Internet of Things(IoTs), such as complex topology information, different degree of association between nodes and overlapping communities. The idea of set pair information grain computing and clustering is introduced to solve the above problems so as to accurately describe the similarity between nodes and fully explore the multi-community structure. A Set Pair Three-Way Overlapping Community Discovery Algorithm for Weighted Social Internet of Things (WSIoT-SPTOCD) is proposed. In the local network structure, which fully considers the topological information between nodes, the set pair connection degree is used to analyze the identity, difference and reverse of neighbor nodes. The similarity degree of different neighbor nodes is defined from network edge weight and node degree, and the similarity measurement method of set pair between nodes based on the local information structure is proposed. According to the number of nodes' neighbors and the connection degree of adjacent edges, the clustering intensity of nodes is defined, and an improved algorithm for initial value selection of k-means is proposed. The nodes are allocated according to the set pair similarity between nodes and different communities. Three-way community structures composed of a positive domain, boundary domain and negative domain are generated iteratively. Next, the overlapping node set is generated according to the calculation results of community node membership. Finally, experiments are carried out on artificial networks and real networks. The results show that WSIoT-SPTOCD performs well in terms of standardized mutual information, overlapping community modularity and F1. 相似文献
109.
110.
Lin Yang Shiwei Ye Zhibo Wang Zhipei Huang Jiankang Wu Yongmei Kong Li Zhang 《半导体学报》2017,38(10):105004-8
A wearable micro-sensor motion capture system with 16 IMUs and an error-compensatory complementary filter algorithm for real-time motion estimation has been developed to acquire accurate 3D orientation and displacement in real life activities. In the proposed filter algorithm, the gyroscope bias error, orientation error and magnetic disturbance error are estimated and compensated, significantly reducing the orientation estimation error due to sensor noise and drift. Displacement estimation, especially for activities such as jumping, has been the challenge in micro-sensor motion capture. An adaptive gait phase detection algorithm has been developed to accommodate accurate displacement estimation in different types of activities. The performance of this system is benchmarked with respect to the results of VICON optical capture system. The experimental results have demonstrated effectiveness of the system in daily activities tracking, with estimation error 0.16 ±0.06 m for normal walking and 0.13 ±0.11 m for jumping motions. 相似文献