全文获取类型
收费全文 | 171800篇 |
免费 | 14848篇 |
国内免费 | 11216篇 |
专业分类
电工技术 | 29385篇 |
技术理论 | 7篇 |
综合类 | 16241篇 |
化学工业 | 9032篇 |
金属工艺 | 6585篇 |
机械仪表 | 15983篇 |
建筑科学 | 14895篇 |
矿业工程 | 6905篇 |
能源动力 | 4674篇 |
轻工业 | 4518篇 |
水利工程 | 5427篇 |
石油天然气 | 5584篇 |
武器工业 | 2641篇 |
无线电 | 12894篇 |
一般工业技术 | 7895篇 |
冶金工业 | 7472篇 |
原子能技术 | 1192篇 |
自动化技术 | 46534篇 |
出版年
2024年 | 572篇 |
2023年 | 1836篇 |
2022年 | 3064篇 |
2021年 | 3849篇 |
2020年 | 4600篇 |
2019年 | 3608篇 |
2018年 | 3209篇 |
2017年 | 4790篇 |
2016年 | 5361篇 |
2015年 | 5973篇 |
2014年 | 11496篇 |
2013年 | 9876篇 |
2012年 | 12531篇 |
2011年 | 13458篇 |
2010年 | 10176篇 |
2009年 | 10466篇 |
2008年 | 10445篇 |
2007年 | 12885篇 |
2006年 | 11545篇 |
2005年 | 10096篇 |
2004年 | 8363篇 |
2003年 | 7388篇 |
2002年 | 5918篇 |
2001年 | 4909篇 |
2000年 | 4232篇 |
1999年 | 3403篇 |
1998年 | 2593篇 |
1997年 | 2299篇 |
1996年 | 1820篇 |
1995年 | 1477篇 |
1994年 | 1257篇 |
1993年 | 903篇 |
1992年 | 726篇 |
1991年 | 546篇 |
1990年 | 416篇 |
1989年 | 367篇 |
1988年 | 258篇 |
1987年 | 152篇 |
1986年 | 111篇 |
1985年 | 109篇 |
1984年 | 154篇 |
1983年 | 118篇 |
1982年 | 115篇 |
1981年 | 79篇 |
1980年 | 53篇 |
1979年 | 64篇 |
1978年 | 48篇 |
1977年 | 48篇 |
1964年 | 13篇 |
1959年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
941.
介绍了6000空分制氧设备中大型透平式压缩机的检修过程中应着重注意的几个问题,主要检修项目的质量控制,以及检修技巧。 相似文献
942.
Gabriele Pannocchia Author Vitae Author Vitae Stephen J. Wright Author Vitae 《Automatica》2007,43(5):852-860
Partial enumeration (PE) is presented as a method for treating large, linear model predictive control applications that are out of reach with available MPC methods. PE uses both a table storage method and online optimization to achieve this goal. Versions of PE are shown to be closed-loop stable. PE is applied to an industrial example with more than 250 states, 32 inputs, and a 25-sample control horizon. The performance is less than 0.01% suboptimal, with average speedup factors in the range of 80-220, and worst-case speedups in the range of 4.9-39.2, compared to an existing MPC method. Small tables with only 25-200 entries were used to obtain this performance, while full enumeration is intractable for this example. 相似文献
943.
944.
Repetitive control is useful if periodic disturbances or setpoints act on a control system. Perfect (asymptotic) disturbance rejection is achieved if the period time is exactly known. The improved disturbance rejection at the periodic frequency and its harmonics is achieved at the expense of a degraded system sensitivity at intermediate frequencies. A convex optimization problem is defined for the design of high-order repetitive controllers, where a trade-off can be made between robustness for changes in the period time and for reduction of the error spectrum in-between the harmonic frequencies. The high-order repetitive control algorithms are successfully applied in experiments with the tracking control of a CD-player system. 相似文献
945.
946.
A pseudohyperbolic problem of optimal control of intratumoral drug distribution is formulated. It takes into account the heterogeneity
of tumor tissues and effects of convection diffusion in a fissured porous medium. A mathematical model constructed and the
corresponding optimal control problem are shown to be correct.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 6, pp. 147–154, November–December 2007. 相似文献
947.
Alireza Karimi Author VitaeAuthor Vitae 《Automatica》2007,43(8):1395-1402
Robust control synthesis of linear time-invariant SISO polytopic systems is investigated using the polynomial approach. A convex set of all stabilizing controllers for a polytopic system is given over an infinite-dimensional space. A finite-dimensional approximation of this set is obtained using the orthonormal basis functions and represented by a set of LMIs thanks to the KYP lemma. Then, an LMI based convex optimization problem for robust pole placement with sensitivity function shaping in two- and infinity-norm is proposed. The simulation results show the effectiveness of the proposed method. 相似文献
948.
A. K. Hansen A. C. Boxer J. L. Ellsworth D. T. Garnier I. Karim J. Kesner M. E. Mauel E. E. Ortiz 《Journal of Fusion Energy》2007,26(1-2):57-60
Plasmas in the Levitated Dipole Experiment (LDX) are formed and sustained currently via two electron cyclotron resonance heating
(ECRH) sources: 2.5 kW at 2.45 GHz and 2.5 kW at 6.4 GHz. An important topic being investigated is how varying the ECRH affects
the confinement and stability of the plasma. We report the results of using different operational combinations of our RF sources,
such as varying the power composition, changing the power levels, and sequencing of the onset time. 相似文献
949.
压力容器材料质量控制的几个重要环节 总被引:2,自引:0,他引:2
针对压力容器材料方面存在的问题,从设计、采购、检验、制造等环节进行了分析,根据实际情况确定材料的质量控制要点。材料使用前要通过各种检测手段,判断材料的真实性,确保所用材料合格;并应从设计、选材、采购、计划、填报内容和选择可靠的供应方等方面加以控制,确保材料的正确使用,为压力容器产品的材料控制提供借鉴。 相似文献
950.
A model of a diversified ecological economic system with lags is proposed and investigated using sufficient optimality conditions.
A turnpike solution of the problem, boundary trajectories, and control switchpoints are found.
__________
Translated from Kibernetika i Sistemnyi Analiz, No. 2, pp. 114–122, March–April 2007. 相似文献