全文获取类型
收费全文 | 8416篇 |
免费 | 86篇 |
国内免费 | 133篇 |
专业分类
电工技术 | 88篇 |
综合类 | 48篇 |
化学工业 | 872篇 |
金属工艺 | 180篇 |
机械仪表 | 426篇 |
建筑科学 | 530篇 |
矿业工程 | 212篇 |
能源动力 | 45篇 |
轻工业 | 2070篇 |
水利工程 | 127篇 |
石油天然气 | 118篇 |
武器工业 | 32篇 |
无线电 | 362篇 |
一般工业技术 | 2882篇 |
冶金工业 | 114篇 |
原子能技术 | 103篇 |
自动化技术 | 426篇 |
出版年
2023年 | 13篇 |
2022年 | 14篇 |
2021年 | 26篇 |
2020年 | 17篇 |
2019年 | 17篇 |
2018年 | 19篇 |
2017年 | 13篇 |
2016年 | 13篇 |
2015年 | 25篇 |
2014年 | 42篇 |
2013年 | 40篇 |
2012年 | 811篇 |
2011年 | 1140篇 |
2010年 | 223篇 |
2009年 | 107篇 |
2008年 | 771篇 |
2007年 | 754篇 |
2006年 | 625篇 |
2005年 | 603篇 |
2004年 | 494篇 |
2003年 | 422篇 |
2002年 | 362篇 |
2001年 | 283篇 |
2000年 | 289篇 |
1999年 | 162篇 |
1998年 | 96篇 |
1997年 | 91篇 |
1996年 | 81篇 |
1995年 | 70篇 |
1994年 | 75篇 |
1993年 | 59篇 |
1992年 | 75篇 |
1991年 | 56篇 |
1990年 | 67篇 |
1989年 | 66篇 |
1988年 | 41篇 |
1987年 | 56篇 |
1986年 | 49篇 |
1985年 | 71篇 |
1984年 | 55篇 |
1983年 | 75篇 |
1982年 | 50篇 |
1981年 | 36篇 |
1980年 | 40篇 |
1979年 | 41篇 |
1978年 | 14篇 |
1977年 | 8篇 |
1976年 | 10篇 |
1966年 | 8篇 |
1965年 | 7篇 |
排序方式: 共有8635条查询结果,搜索用时 301 毫秒
21.
22.
del Campo I Basterretxea K Echanobe J Bosque G Doctor F 《IEEE transactions on systems, man, and cybernetics. Part B, Cybernetics》2012,42(2):501-512
This paper presents the development of a neuro-fuzzy agent for ambient-intelligence environments. The agent has been implemented as a system-on-chip (SoC) on a reconfigurable device, i.e., a field-programmable gate array. It is a hardware/software (HW/SW) architecture developed around a MicroBlaze processor (SW partition) and a set of parallel intellectual property cores for neuro-fuzzy modeling (HW partition). The SoC is an autonomous electronic device able to perform real-time control of the environment in a personalized and adaptive way, anticipating the desires and needs of its inhabitants. The scheme used to model the intelligent agent is a particular class of an adaptive neuro-fuzzy inference system with piecewise multilinear behavior. The main characteristics of our model are computational efficiency, scalability, and universal approximation capability. Several online experiments have been performed with data obtained in a real ubiquitous computing environment test bed. Results obtained show that the SoC is able to provide high-performance control and adaptation in a life-long mode while retaining the modeling capabilities of similar agent-based approaches implemented on larger computing machines. 相似文献
23.
San-Vicente G Aguinaga I Tomás Celigüeta J 《IEEE transactions on visualization and computer graphics》2012,18(2):228-241
Mass-Spring Models (MSMs) are used to simulate the mechanical behavior of deformable bodies such as soft tissues in medical applications. Although they are fast to compute, they lack accuracy and their design remains still a great challenge. The major difficulties in building realistic MSMs lie on the spring stiffness estimation and the topology identification. In this work, the mechanical behavior of MSMs under tensile loads is analyzed before studying the spring stiffness estimation. In particular, the performed qualitative and quantitative analysis of the behavior of cubical MSMs shows that they have a nonlinear response similar to hyperelastic material models. According to this behavior, a new method for spring stiffness estimation valid for linear and nonlinear material models is proposed. This method adjusts the stress-strain and compressibility curves to a given reference behavior. The accuracy of the MSMs designed with this method is tested taking as reference some soft-tissue simulations based on nonlinear Finite Element Method (FEM). The obtained results show that MSMs can be designed to realistically model the behavior of hyperelastic materials such as soft tissues and can become an interesting alternative to other approaches such as nonlinear FEM. 相似文献
24.
Intergranular stress corrosion cracking(ISCC) of α-brass in neutral Mattsson's solutionwas found to be controlled by an unusual"W"-shaped galvanic cell whose cathode is thegrain boundary oxide film (G.B.0. film) andsurface film and the anode is fresh metal atthe cracked tip on both sides of the G.B.0.film. Redox reactions involved in the cellhave been proposed here. According to thismdel, initidtion of ISCC is caused by therupturing of surface film along grain boundaries,thus forming a galvanic cell. Propagation ofISCC resulted from alternate advances of G.B.0.film and dissolution on both sides of G.B.0.film caused by the effect of electrochemicalreaction. This work developed an effective approachto investigate the embrittlement process atthe tip of the crack, by increasing the lengthof the embrittlement region through constantstrain test and distinguishing the morphologyand the nature of the corrosion products byoptical microscopy and scanning electronmicroscopy (SEH). 相似文献
25.
A technique is described for monitoring and analysis of the angular displacement of the human torso. The technique is based on the use of miniature electromechanical inclinometers and video recording. The system was developed for continuous measurement of the angular displacement of spinal segments in the sagittal plane during all stages of lifting. Angular displacements of the cervical, thoracic and lumbar regions were obtained from a dynamic lifting case study using a digital processing system. The geometrical changes of the torso during five prescribed stages were measured. The system revealed good accuracy with high correlation coefficient scores for a wide range of lifting tasks in a comparative laboratory study. This paper describes the monitoring technique; the system's advantages, disadvantages and measuring accuracy are discussed. 相似文献
26.
The ability of Lactobacillus jensenii and Streptococcus 17SB to inbhibit Escherichia coli was demonstrated. The practical application of the inhibition was examined. Possible roles for several factors in the mechanism of inhibition by Lactobacillus jensenii and Streptococcus 17SB are briefly discussed. The effects of pH reached and acids produced by starters on the growth of Escherichia coli are described. 相似文献
27.
Claesson I Salomonsson G 《IEEE transactions on ultrasonics, ferroelectrics, and frequency control》1988,35(5):582-592
The resolution in ultrasonic images decreases with depth when using traditional time-gain compensation (TGC) of the received signal. To reduce this effect, both frequency-dependent and depth-dependent compensation is introduced. A time-varying digital filtering method is presented for this purpose, which is based on Wiener filtering. Images obtained from a simulated tissue equivalent are presented and the frequency-compensated images are compared to conventional TGC-compensated images. It is shown that the improvement in resolution using frequency-dependent compensation is considerable when the signal-to-noise ratio in the received signal is high. 相似文献
28.
The number of aerobic bacteria on the skin of pork carcasses was measured at seven different points on the slaughtering line in order to study the hygienic effect of pre-scalding brushing on the contamination level of carcasses. Eighty carcasses were investigated, of which 40 were brushed before scalding and 40 served as controls. Samples were excised from three sites: back, abdomen and ham. The total number of samples was 1368. The cleaning monitoring of the pre-scalding brushing machine and the blackscraping machine was done at the same time. After singeing and blackscraping there were significant differences (P<0·05) between brushed and non-brushed ham sites. After singeing, brushed ham sites had a contamination level of 2·11 (log(10) cm(-2)) and non-brushed ham sites a level of 1·57. After blackscraping the contamination of brushed ham sites was 3·45 (log(10) cm(-2)) and that of non-brushed ham sites 3·26. At the end of the slaughtering line brushed carcasses were more contaminated than those not brushed, although this difference was not significant. 相似文献
29.
30.