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71.
设计一种时分降低滤波器用来进行运载体惯导系统的动态对准和传递对准,假定运载体惯导系统已标定的。在运载体水平直线运动的短时间内,两个二阶滤波以时分工作方式估计平台水平失调角,在消除水平失调角后,运载体在垂直与当地垂线的水平面内机动,此时用一个三阶(或四阶)滤波器来估计方位失调角,另外,在本文中给出该滤波器的数据压缩算法,来提高估计精度。  相似文献   
72.
本文介绍了计算机电信集成技术及其进展,特别详尽分析了它的三种实现形式:点对点形式、交换机-计算机形式、客户/服务器形式。  相似文献   
73.
In industry continuous or impulse noise does not occur exclusively; rather it is a combination of both. If low-level continuous noise or impulse noise (below 120 dB) is added to an already existing high-level continuous noise this often numerically causes no essential increase in the rating level. Yet, it cannot be expected that also aural strain of these exposures is always negligible. Therefore, in a cross-over test series, ten male subjects (Ss) were exposed to white noise of 94 dB(A) for 1 h (TS I), energy-equivalent to an 8 h-rating level LArd of 85 dB(A). In a second test series (TS II) the same exposure was combined with 900 energetically negligible 5-ms impulses with a noise level of 113 dB(A) which increased the rating level by only 0.4 dB. The noise exposure of TS I and TS II was followed by an idealized resting phase in a soundproof cabin. In a third test series (TS III) the continuous noise of 94 dB(A) / 1 h was followed by 3 h of white noise at 70 dB(A). Such an additional load increases the LArd by merely 0.1 dB to 85.1 dB(A). In all three test series, the noise-induced temporary threshold shift (TTS2) and its restitution were measured. The continuous noise exposure of 94 dB(A) for 1 h was associated with a TTS2 of around 20 dB which disappeared completely after about 2 h. The additional impulse noise caused a small increase in the TTS2 and a prolongation of the restitution time. The maximum mean temporary threshold shift for the group increased only slightly (from 22.5 to 25.9 dB, which nevertheless can be statistically proven at a significance level of p 0.99). Yet, more importantly, the restitution time increased from 126 to 175 min, i. e. 3 h, which can be statistically proven at a significance level of p0.95. The TTS2-values of TS III did not differ significantly from those resulting from TS I. That was expected as the conditions up to that point in time were identical. But due to the additional subsequent exposure, the mean restitution time increased considerably from 126 min up to 240 min (4 h). The mean total physiological cost represented by the integrated restitution temporary threshold shift (IRTTS) increased in TS II by approximately 40% and in TS III even by 140%.

Relevance to industry

The results of the study show that levels of noise which have no influence on the rating level which traditionally is calculated according to the energy-equivalence principle are often of great importance, as they can lead to considerably prolonged restitution times. Therefore, the purely energy-equivalent determination of the rating level of both impulse noise and low sound levels can lead to an underestimation of latent problems so that over time a reversible TTS can evolve into a permanent threshold shift. The results are also of importance for the acoustic design of break rooms for noise-exposed workers. There should be conditions that allow an undisturbed restitution of hearing.  相似文献   

74.
A.  J. A.  I.  J.  J.  J.  C. 《Sensors and actuators. A, Physical》2004,110(1-3):395-400
The fabrication and characterization of an optical accelerometer based on silicon technology and using BESOI wafers is presented. Instead of the standard total internal reflection (TIR) waveguides, AntiResonant Reflecting Optical Waveguides (ARROW) have been used. On the basis of a quad beam accelerometer design, a sensing waveguide has been placed on the seismic mass. Its misalignment with the waveguides located at the frame allows measuring the acceleration. The mechanical structure has been designed so as to have a span of 2 μm, that should provide with a sensitivity of 4.6 dB/g. Reference waveguides measured by end-fire coupling have low radiation and insertion losses (0.3 and 2.5 dB, respectively). High insertion losses are observed due to imperfections in polishing when V-grooves with glass anodic bonding are used. This fact causes the reduction of its sensibility to 2.3 dB/g.  相似文献   
75.
Flood control management system for reservoirs   总被引:1,自引:0,他引:1  
Flood disaster is one of the most damaging natural disasters in China, with annual average losses more than 200 billion yuan in recent years. After 1995 floods in the Liaohe River and 1998 floods in the Yangtze River, the governments from national to local have realized that the flood control operation of reservoirs can play a major role in alleviating flood losses but there are some problems in flood control management for reservoirs. Most of the existing flood control management systems for reservoir were established for special purposes and are lack of data share and communication with governments, it is very difficult for decision-making departments to get real-time information in short time. Thus, a national programming about flood control management system for reservoirs is presented. The paper is a summary of the outcome of national programming about the flood control management system for reservoirs in China. The background, objectives, main challenges and main contents of the programming are introduced. The main focus is on the issues of the software integration flood control management system for reservoirs. Emphasis is concentrated on the flowchart design of the system and its core components. The current system can be applied to a river control center or a single reservoir because of using the national standard databases and easily integrated into the national flood control system in the future. An application system is briefly introduced in order to understand the system.  相似文献   
76.
Functional tolerancing is classically based onto dimension chains to respect functional requirements. Tolerance synthesis deals with dimensions optimization in order to maximize tolerances. This method is classically used taking into account only geometrical defaults. Mechanisms concerned with significant variation of temperature in different stages of functioning, require taking into account thermal expansion. This expansion has a direct impact onto clearances and dimensions of the mechanism. The purpose of this paper is to consider thermal expansion of parts integrated within functional tolerancing. In particular, this paper will compare the effects of tolerancing, thermal expansion and uncertainties of temperature in order to know if uncertainties must be included in the tolerance chain or can be neglected as second order. A basic experimental mechanism is used to show this method and the differences between the two approaches.  相似文献   
77.
基于多代理的分布式可集成MES框架研究   总被引:2,自引:0,他引:2  
分析了敏捷制造模式下对MES的要求,给出了支持敏捷制造的基于多代理的分布式可集成MES框架,框架由三层组成,MES核心层完成通用的MES功能,外部系统抽象层是与MES交互的外部系统的抽象,适配器层完成了框架与外部系统的连接,详细地描述各层中代理的功能以及它们之间的交互,并给出了基于JADE的系统实现。  相似文献   
78.
针对集成温度传感器AD590应用中存在的非线性问题,介绍了AD590的特点、工作原理及非线性误差产生的原因,重点讨论了实际应用中AD590在环境温度采集时温度补偿的几种方法,实验结果表明这些方法成本低、误差小、精度高。  相似文献   
79.
利用积分多谱给出了一种平稳时间序列的高斯性检验方法,并通过仿真实验进行了验证。  相似文献   
80.
基于标准0.18μm CMOS工艺和低功耗设计方法设计了集成温度传感器所需的3个重要电流产生电路,即与温度成正比的电流,与温度成反比的电流和稳定的、不随温度及电源电压变化的电流产生电路。采用低功耗设计方法解决了自然效应对温度传感器的影响。采用TSMC所提供的BSIM3V3模型进行仿真,电路在-40~120℃具有高线性度、高稳定度。同时电路具有低压、低功耗的优点,并且有良好的移植性,可使用于更多更广泛的吻合。  相似文献   
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