全文获取类型
收费全文 | 63294篇 |
免费 | 6660篇 |
国内免费 | 6062篇 |
专业分类
电工技术 | 6665篇 |
技术理论 | 6篇 |
综合类 | 7303篇 |
化学工业 | 3025篇 |
金属工艺 | 786篇 |
机械仪表 | 3904篇 |
建筑科学 | 2545篇 |
矿业工程 | 1196篇 |
能源动力 | 2045篇 |
轻工业 | 1172篇 |
水利工程 | 1212篇 |
石油天然气 | 774篇 |
武器工业 | 690篇 |
无线电 | 4562篇 |
一般工业技术 | 4399篇 |
冶金工业 | 1449篇 |
原子能技术 | 211篇 |
自动化技术 | 34072篇 |
出版年
2024年 | 274篇 |
2023年 | 889篇 |
2022年 | 972篇 |
2021年 | 1286篇 |
2020年 | 1746篇 |
2019年 | 1771篇 |
2018年 | 1695篇 |
2017年 | 2145篇 |
2016年 | 2400篇 |
2015年 | 2340篇 |
2014年 | 3750篇 |
2013年 | 5093篇 |
2012年 | 3722篇 |
2011年 | 4469篇 |
2010年 | 3301篇 |
2009年 | 3919篇 |
2008年 | 4013篇 |
2007年 | 4422篇 |
2006年 | 3878篇 |
2005年 | 3368篇 |
2004年 | 2728篇 |
2003年 | 2496篇 |
2002年 | 2150篇 |
2001年 | 1768篇 |
2000年 | 1670篇 |
1999年 | 1429篇 |
1998年 | 1226篇 |
1997年 | 1006篇 |
1996年 | 882篇 |
1995年 | 763篇 |
1994年 | 657篇 |
1993年 | 590篇 |
1992年 | 453篇 |
1991年 | 415篇 |
1990年 | 322篇 |
1989年 | 278篇 |
1988年 | 219篇 |
1987年 | 183篇 |
1986年 | 142篇 |
1985年 | 184篇 |
1984年 | 192篇 |
1983年 | 177篇 |
1982年 | 151篇 |
1981年 | 99篇 |
1980年 | 74篇 |
1979年 | 86篇 |
1978年 | 62篇 |
1977年 | 70篇 |
1976年 | 21篇 |
1975年 | 13篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
Technology can take many forms from the development of sophisticated electronics to the application of basic procedural principles. Technology transfer can also take several forms, however, in this case, it is the transfer of technological principles between application domains that is of primary interest. This paper presents a framework (the Five ‘M’s framework) that can be used to consider the likely success of technology transfer. The framework is based upon a sociotechnical system approach. The framework is illustrated with an evaluation of the introduction of intelligent cruise control into motor vehicles. It is argued that this is a technological concept first developed as an aerospace application in the form of the autopilot. In this case, it is argued that the transfer of this technology in its current form may potentially compromise safety. 相似文献
92.
A. Aryshev S. Araki P. Karataev T. Naito N. Terunuma J. Urakawa 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2007,580(3):1544-1551
A fast room temperature microwave detection system based on the Schottky Barrier-diode detector was created at the KEK ATF (Accelerator Test Facility). It was tested using Coherent Synchrotron Radiation (CSR) generated by the 1.28 GeV electron beam in the damping ring. The speed performance of the detection system was checked by observing the CSR from a multi-bunch (2.8 ns bunch separation time) beam. The theoretical estimations of CSR power yield from an edge of bending magnet as well as new injection tuning method are presented. A very high sensitivity of CSR power yield to the longitudinal electron distribution in a bunch is discussed. 相似文献
93.
94.
研究了多径信道下OFDM系统的一种新的载波频率跟踪算法,这种算法以判决反馈和接收端的时域信号重构为基础。推导了估计结果的精确解,比较了使用原估计结果和新的估计结果进行频偏补偿时系统跟踪性能的不同。通过对算法的仔细分析,发现除了通常的加性噪声外,信道估计误差、子载波数目和子载波的调制方式也影响频偏的估计结果和跟踪范围,而且子载波的数目和调制方式是决定性的因素。这种频率跟踪方法的优点是即使在很低的信噪比下仍然能获得高的跟踪精度,且实现相对简单。 相似文献
95.
96.
97.
George Weiss 《Mathematics of Control, Signals, and Systems (MCSS)》1991,4(2):193-203
We give an elementary proof of the well-known fact that shift-invariant operators onL
2[0, ∞) are represented by transfer functions which are bounded and analytic on the right open half-plane. We prove a generalization
to Banach space-valuedL
p
-functions, where 1≤p<∞. We show that the result no longer holds forp=∞.
This research was supported partially by the Weizmann Fellowship, and partially by the Air Force Office of Scientific Research
under Contract F49620-86-C-0111. 相似文献
98.
We obtain a necessary and sufficient condition for a discrete-time nonlinear system to be locally state equivalent to the nonlinear observer form. The result looks similar to the continuous counterpart except for the fact that Ad-operation is utilized instead of ad-operation. 相似文献
99.
The objective of this note is to propose a method for stabilization of structurally fixed modes in expansions of LTI dynamic systems in the scope of overlapping decentralized control design based on the expansion/contraction framework, enabling successful design for a broader class of problems than considered so far. The method is based on a judicious choice of complementary matrices in the expanded space. Numerical examples are provided to illustrate simplicity and efficiency of the proposed approach. 相似文献
100.
A constant trend towards more compact mechanical systems with higher power densities and increased thermo-mechanical loads emphasises the importance of the development of new design approaches and novel tribological systems. Ignoring this may cause a significant slow down in technological and industrial development. Tribotronics or active tribology based on adaptive performance is thought of as being critical in the implementation of smart machine concepts. Recognition of the importance of tribotronics, or active control of system loss outputs, such as those through friction and wear will have significant beneficial economic consequences as a result of the associated accelerated rate of technological progress. These smart tribotronic systems can be embedded in a great variety of machines and mechanisms. If this integration is made at the design stage, products that are more flexible, efficient and reliable can be produced. The concept of tribotronics is presented and discussed in this paper. Some illustrative examples that show the feasibility of an “active” approach are given. In addition, various possibilities already reported in literature are discussed. 相似文献