全文获取类型
收费全文 | 22318篇 |
免费 | 2810篇 |
国内免费 | 2158篇 |
专业分类
电工技术 | 5635篇 |
技术理论 | 1篇 |
综合类 | 2268篇 |
化学工业 | 451篇 |
金属工艺 | 828篇 |
机械仪表 | 2344篇 |
建筑科学 | 495篇 |
矿业工程 | 464篇 |
能源动力 | 386篇 |
轻工业 | 183篇 |
水利工程 | 442篇 |
石油天然气 | 233篇 |
武器工业 | 281篇 |
无线电 | 4286篇 |
一般工业技术 | 977篇 |
冶金工业 | 674篇 |
原子能技术 | 208篇 |
自动化技术 | 7130篇 |
出版年
2024年 | 110篇 |
2023年 | 323篇 |
2022年 | 439篇 |
2021年 | 560篇 |
2020年 | 632篇 |
2019年 | 551篇 |
2018年 | 591篇 |
2017年 | 816篇 |
2016年 | 957篇 |
2015年 | 1075篇 |
2014年 | 1466篇 |
2013年 | 1529篇 |
2012年 | 1741篇 |
2011年 | 1911篇 |
2010年 | 1456篇 |
2009年 | 1549篇 |
2008年 | 1489篇 |
2007年 | 1763篇 |
2006年 | 1451篇 |
2005年 | 1218篇 |
2004年 | 941篇 |
2003年 | 835篇 |
2002年 | 647篇 |
2001年 | 573篇 |
2000年 | 497篇 |
1999年 | 403篇 |
1998年 | 299篇 |
1997年 | 259篇 |
1996年 | 222篇 |
1995年 | 165篇 |
1994年 | 161篇 |
1993年 | 145篇 |
1992年 | 102篇 |
1991年 | 87篇 |
1990年 | 76篇 |
1989年 | 46篇 |
1988年 | 28篇 |
1987年 | 24篇 |
1986年 | 13篇 |
1985年 | 18篇 |
1984年 | 19篇 |
1983年 | 24篇 |
1982年 | 13篇 |
1981年 | 9篇 |
1980年 | 9篇 |
1979年 | 6篇 |
1978年 | 4篇 |
1976年 | 4篇 |
1964年 | 6篇 |
1958年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
1.
The load applied to a machine tool feed drive changes during the machining process as material is removed. This load change alters the Coulomb friction of the feed drive. Because Coulomb friction accounts for a large part of the total friction the friction compensation control accuracy of the feed drives is limited if this nonlinear change in the applied load is not considered. This paper presents a new friction compensation method that estimates the machine tool load in real time and considers its effect on friction characteristics. A friction observer based on a Kalman filter with load estimation is proposed for friction compensation control considering the applied load change. A specially designed feed drive testbed that enables the applied load to be modified easily was constructed for experimental verification. Control performance and friction estimation accuracy are demonstrated experimentally using the testbed. 相似文献
2.
段潇乐 《湖南工业职业技术学院学报》2015,(1):82-84
本研究检测了直接和间接两种修正性反馈与国内高职理科学生写作水平的关系。本实验持续五周,将150名学习者分为直接反馈组、间接反馈组及控制组,共安排了一次预先测试,,一次即时后测和一次延时后测,并分别对各组进行考察,结果显示两个实验组进步显著,且直接反馈效果最明显。 相似文献
3.
The paper considers the problem of stabilization of systems possessing a multiple zero eigenvalue at the origin. The controller that we propose, uses multiple delayed measurements instead of derivative terms. Doing so, we increase the performances of the closed loop in presence of system uncertainties and/or noisy measurements. The problem formulation and the analysis is presented through a classical engineering problem which is the stabilization of an inverted pendulum on a cart moving horizontally. On one hand, we perform a nonlinear analysis of the center dynamics described by a three dimensional system of ordinary differential equations with a codimension-three triple zero bifurcation. On the other hand, we present the complementary stability analysis of the corresponding linear time invariant system with two delays describing the behavior around the equilibrium. The aim of this analysis is to characterize the possible local bifurcations. Finally, the proposed control scheme is numerically illustrated and discussed. 相似文献
4.
论精神损害的国家赔偿责任 总被引:1,自引:0,他引:1
姚曙明 《湖南冶金职业技术学院学报》2006,6(3):313-316
国家的侵权行为造成相对人的精神损害应当承担赔偿责任是当今世界国家赔偿制度的发展潮流与趋势.确立精神损害的国家赔偿责任对社会公平正义的实现、人权的保护及促使国家公职人员依法行使职权具有重大的意义,因而应在基于我国国情的基础上,构建我国的精神损害国家赔偿制度. 相似文献
5.
根据某面板堆石坝施工期、蓄水初期以及几年来的沉降观测资料,对坝体填筑材料计算参数进行反馈分析,得出了能够反映坝体实际变形的弹塑性应力变形计算参数,有利于今后建立大坝变形预报模型,更准确地把握大坝实时运行状态。 相似文献
6.
Kruk Menno R.; Halász József; Meelis Wout; Haller József 《Canadian Metallurgical Quarterly》2004,118(5):1062
Aggressive behavior induces an adrenocortical stress response, and sudden stressors often precipitate violent behavior. Experiments in rats revealed a fast, mutual, positive feedback between the adrenocortical stress response and a brain mechanism controlling aggression. Stimulation of the aggressive area in the hypothalamus rapidly activated the adrenocortical response, even in the absence of an opponent and fighting. Hypothalamic aggression, in turn, was rapidly facilitated by a corticosterone injection in rats in which the natural adrenocortical stress response was prevented by adrenalectomy. The rapidity of both effects points to a fast, mutual, positive feedback of the controlling mechanisms within the time frame of a single conflict. Such a mutual facilitation may contribute to the precipitation and escalation of violent behavior under stressful conditions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
7.
8.
本文提出励磁电流可自动控制的他励式双高调速系统设计方案。系统在提升特别是在下放重物时,具有较硬的机械性;在负载10-100%的变化范围内,可实现最大偏差Δnmax/nmin100%≤10%,调速范围D≥10;在满载运行条件下,可节约电能80%以上。 相似文献
9.
A serious problem in motion control is the occurrence of torque ripple. Since a direct drive (DD) motor with a magnet rotor uses a rare-earth magnet, the torque ripple is more serious than that of conventional servomotors. This paper presents an auto-compensation of torque ripple using a software-implemented torque observer. The frequency and amplitude of torque ripple can be obtained in the controller by using the estimated torque from an observer, and the autonomous generation of a compensating current component for a torque ripple is possible. The proposed algorithm has been verified by experiments. 相似文献
10.