全文获取类型
收费全文 | 56938篇 |
免费 | 6498篇 |
国内免费 | 3016篇 |
专业分类
电工技术 | 4184篇 |
技术理论 | 2篇 |
综合类 | 4465篇 |
化学工业 | 8864篇 |
金属工艺 | 3205篇 |
机械仪表 | 3728篇 |
建筑科学 | 4716篇 |
矿业工程 | 1672篇 |
能源动力 | 1683篇 |
轻工业 | 4722篇 |
水利工程 | 1035篇 |
石油天然气 | 2947篇 |
武器工业 | 549篇 |
无线电 | 6905篇 |
一般工业技术 | 5990篇 |
冶金工业 | 2430篇 |
原子能技术 | 1118篇 |
自动化技术 | 8237篇 |
出版年
2025年 | 4篇 |
2024年 | 882篇 |
2023年 | 1203篇 |
2022年 | 2206篇 |
2021年 | 2760篇 |
2020年 | 2194篇 |
2019年 | 1730篇 |
2018年 | 1916篇 |
2017年 | 2069篇 |
2016年 | 1888篇 |
2015年 | 2452篇 |
2014年 | 3037篇 |
2013年 | 3331篇 |
2012年 | 3701篇 |
2011年 | 3936篇 |
2010年 | 3567篇 |
2009年 | 3425篇 |
2008年 | 3397篇 |
2007年 | 3198篇 |
2006年 | 3179篇 |
2005年 | 2708篇 |
2004年 | 1831篇 |
2003年 | 1650篇 |
2002年 | 1754篇 |
2001年 | 1560篇 |
2000年 | 1363篇 |
1999年 | 1163篇 |
1998年 | 751篇 |
1997年 | 707篇 |
1996年 | 657篇 |
1995年 | 456篇 |
1994年 | 416篇 |
1993年 | 296篇 |
1992年 | 266篇 |
1991年 | 185篇 |
1990年 | 122篇 |
1989年 | 119篇 |
1988年 | 96篇 |
1987年 | 62篇 |
1986年 | 59篇 |
1985年 | 29篇 |
1984年 | 27篇 |
1983年 | 25篇 |
1982年 | 21篇 |
1981年 | 14篇 |
1980年 | 17篇 |
1979年 | 6篇 |
1976年 | 2篇 |
1959年 | 9篇 |
1951年 | 2篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
Easy and hard magnetization curves of Nd_2Co_(14)B compound have been measured withextracting-sample-magnetometer(μ_0H_(max)=6T)at 10~300 K.Magnetic anisotropy constants K_1 and K_2have been determined by fitting the hard magnetization curves,in which only K_1 ,K_2 and misalignment anglehave been taken as fitting parameters.The values of K_1 and K_2 at 4.2 K were derived by extrapolation.Anisotropy coefficients,x_2~° and x_4~°were derived from the anisotropy constants.The anisotropy constant K_2increases rapidly with increasing temperature when TT_(sr).The temperature depen-dence of the magnetic anisotropy coefficient x_2~° was fitted with the formula.The anisotropy coefficients x_2~°can be well described by the tenth-power law from 4.2 K to T_(sr)and by the sixth-power law from T_(sr_ to 300 K. 相似文献
42.
43.
44.
45.
Sibang Liu Shuzhi Sam Ge Zhongliang Tang 《International Journal of Control, Automation and Systems》2016,14(4):924-938
This paper presents a modular designed autonomous bolt tightening shaft system with an adaptive fuzzy backstepping control approach developed for it. The bolt tightening shaft is designed for the autonomous bolt tightening operation, which has huge potential for industry application. Due to the inherent nonlinear and uncertain properties, the bolt tightening shaft and the bolt tightening process are mathematically modeled as an uncertain strict feedback system. With the adaptive backstepping and approximation property of fuzzy logic system, the controller is recursively designed. Based on the Lyapunov stability theorem, all signals in the closed-loop system are proved to be uniformly ultimately bounded and the torque tracking error exponentially converges to a small residue. And the effectiveness and performance of the proposed autonomous system are verified by the simulation and experiment results on the bolt tightening shaft system. 相似文献
46.
Wenhai Qi Xianwen Gao 《International Journal of Control, Automation and Systems》2016,14(6):1413-1420
The paper is concerned with the problem of positive L 1-gain filter design for positive continuous-time Markovian jump systems with partly known transition rates. Our aim is to design a positive full-order filter such that the corresponding filtering error system is positive and stochastically stable with L 1-gain performance. By applying a linear co-positive Lyapunov function and free-connection weighting vectors, the desired positive L 1-gain filter is provided. The obtained theoretical results are demonstrated by numerical examples. 相似文献
47.
48.
介绍了驱动开发技术背景及应用,讲述SSDTHOOK方法,实现监控NtCreateProcessEx系统服务。RING3应用程序和驱动程序的交互,RING3应用程序和驱动程序的同步实现基于驱动的进程创建监控。 相似文献
49.
祁鑫 《计算机工程与科学》2011,33(Z1)
针对当今社会对软件工程专业人才培养提出的新需求,以校企联合培养班"订单式"培养为契机,以市场为导向,从设置柔性课程体系入手,全面实施教学改革,探索创新人才培养模式。 相似文献
50.
On the basis of the available thermodynamic parameters, the atomic mobilities of Nb and Zr in bcc Nb–Zr alloys are critically assessed as functions of temperatures and compositions by the CALPHAD method, where self-diffusion coefficients, impurity diffusion coefficients, tracer diffusion coefficients, interdiffusion coefficients and concentration curves are simultaneously optimized. Comparisons between the calculated and experimentally measured diffusion coefficients are made, where good agreement is evident. In addition, the obtained mobility parameters can reproduce a reasonable concentration profile for the Nb/Zr diffusion couple annealed at 1868 K for 5400 s. 相似文献