全文获取类型
收费全文 | 475篇 |
免费 | 31篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 13篇 |
综合类 | 1篇 |
化学工业 | 113篇 |
金属工艺 | 11篇 |
机械仪表 | 11篇 |
建筑科学 | 13篇 |
矿业工程 | 2篇 |
能源动力 | 14篇 |
轻工业 | 53篇 |
水利工程 | 2篇 |
石油天然气 | 3篇 |
无线电 | 68篇 |
一般工业技术 | 90篇 |
冶金工业 | 40篇 |
原子能技术 | 4篇 |
自动化技术 | 73篇 |
出版年
2023年 | 5篇 |
2022年 | 5篇 |
2021年 | 11篇 |
2020年 | 10篇 |
2019年 | 19篇 |
2018年 | 11篇 |
2017年 | 10篇 |
2016年 | 16篇 |
2015年 | 10篇 |
2014年 | 14篇 |
2013年 | 29篇 |
2012年 | 26篇 |
2011年 | 28篇 |
2010年 | 22篇 |
2009年 | 19篇 |
2008年 | 16篇 |
2007年 | 31篇 |
2006年 | 22篇 |
2005年 | 13篇 |
2004年 | 10篇 |
2003年 | 5篇 |
2002年 | 11篇 |
2001年 | 11篇 |
2000年 | 4篇 |
1999年 | 8篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 13篇 |
1995年 | 13篇 |
1994年 | 6篇 |
1993年 | 8篇 |
1991年 | 6篇 |
1990年 | 5篇 |
1989年 | 3篇 |
1988年 | 5篇 |
1987年 | 6篇 |
1986年 | 5篇 |
1985年 | 7篇 |
1984年 | 5篇 |
1983年 | 8篇 |
1982年 | 4篇 |
1981年 | 8篇 |
1977年 | 5篇 |
1976年 | 5篇 |
1975年 | 4篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 2篇 |
1965年 | 1篇 |
1958年 | 1篇 |
排序方式: 共有511条查询结果,搜索用时 31 毫秒
1.
Francois P.-L. Monerie M. Vassallo C. Durteste Y. Alard F.R. 《Lightwave Technology, Journal of》1989,7(3):500-513
Depending on the spectal width of the source illuminating an interferometer, measurement procedures can utilize either the whole interferogram, or only the fringe envelope, or only the fringe quick oscillations. With an ultraband spectrum source, a simplified adaptation of the methods of Fourier transform spectroscopy yields the variations of the test-fiber propagation constant over the whole wavelength-interval of the source. Chromatic dispersion can then be computed from a single interferogram. With narrower spectrum sources, only the fringe envelopes are utilized and yield measurements of mode delay, with application to chromatic and polarization mode dispersion. In this case, however, interferograms at several wavelengths are necessary. With even narrower spectrum sources, the fringe quick oscillations provide measurements of phase shifts, related to changes in the mode propagation constant, when outside perturbations are applied to the test fiber. A direct method for measuring the third-order nonlinear susceptibilities is discussed. In this case the outside perturbation is an intense pump laser field 相似文献
2.
3.
Francois Pellissier 《Journal of chemical ecology》1993,19(10):2105-2114
The aim of this investigation was to determine the impact ofp-hydroxyacetophenone,p-hydroxybenzoic acid, catechol, and protocatechuic acid on respiration of two spruce mycorrhizal fungi:Laccaria laccata andCenococcum graniforme. These phenols are produced byVaccinium myrtillus,Athyrium filixfemina, andPicea abies, predominant species of spruce forests in the Alps, and they are also present in humic solutions at 10–10 M or 10–5 M. Respiration of the two fungi was inhibited by the four phenolic acids, even at concentrations ranging from 10–5 M to 10–7 M. These data show phenolic acids from humic solutions have biological activity at extremely low concentrations, suggesting a contribution ofV. myrtillus, A. filixfemina, andP. abies to allelopathic inhibition of mycorrhizal fungi. 相似文献
4.
The cooling power of aqueous solutions of ethylene oxide-propylene oxide copolymers are studied with a silver standard sample by using two apparatuses quench with injection and quench with agitation. For temperature T>400°C, the viscosity plays the predominant role; for T<400°C, the cooling is controlled by the polymer precipitation and the cooling rate decreases by lowering the cloud point of the polymer solution. This work demonstrates the possibility of adjusting the cooling curves by taking into account the thermodynamical properties of the polymer. 相似文献
5.
Yogesh Singh Chauhan Renaud Gillon Benoit Bakeroot Francois Krummenacher Michel Declercq Adrian Mihai Ionescu 《Solid-state electronics》2007,51(11-12):1581
An EKV-based high voltage MOSFET model is presented. The intrinsic channel model is derived based on the charge based EKV-formalism. An improved mobility model is used for the modeling of the intrinsic channel to improve the DC characteristics. The model uses second order dependence on the gate bias and an extra parameter for the smoothening of the saturation voltage of the intrinsic drain. An improved drift model [Chauhan YS, Anghel C, Krummenacher F, Ionescu AM, Declercq M, Gillon R, et al. A highly scalable high voltage MOSFET model. In: IEEE European solid-state device research conference (ESSDERC), September 2006. p. 270–3; Chauhan YS, Anghel C, Krummenacher F, Maier C, Gillon R, Bakeroot B, et al. Scalable general high voltage MOSFET model including quasi-saturation and self-heating effect. Solid State Electron 2006;50(11–12):1801–13] is used for the modeling of the drift region, which gives smoother transition on output characteristics and also models well the quasi-saturation region of high voltage MOSFETs. First, the model is validated on the numerical device simulation of the VDMOS transistor and then, on the measured characteristics of the SOI-LDMOS transistor. The accuracy of the model is better than our previous model [Chauhan YS, Anghel C, Krummenacher F, Maier C, Gillon R, Bakeroot B, et al. Scalable general high voltage MOSFET model including quasi-saturation and self-heating effect. Solid State Electron 2006;50(11–12):1801–13] especially in the quasi-saturation region of output characteristics. 相似文献
6.
Electrical conductivity, thermoelectrical power and thermal conductivity measurements on boron carbide samples show that the electrical conductivity follows the small polaron hopping theory and that thermal conductivity occurs by phonon diffusion. The evolution of these properties with carbon content illustrates the particular role played by the 13.3 at% C compound in the phase homogeneity range B10.5C to B4C. The value of the figure of merit (0.85×10–3 K at 1250 K) proves that this particular boron carbide compound could be a very interesting candidate material for high-temperature thermoelectrical conversion. 相似文献
7.
Issam El Gmati Pierre Francois Calmon Ali Boukabache Patrick Pons Hatem Boussetta Mouhamed Adel Kallala Kamel Besbes 《Microsystem Technologies》2014,20(6):1085-1091
In this work, RF MEMS continuous reversible variable inductor has been fabricated by using microelectronic technology and lamination process. We review, evaluate and compare this variable inductor with other work. The proposed inductor is a dual circular coil and has an inductance of few nH. The fundamental idea is to place a liquid droplet between the metal turns of a coil in order to modify the capacitive/resistive coupling between metal tracks and hence to change the stored magnetic energy. The SU-8 resin was used to realize the microfluidic channels and Au as metallic tracks. To prove the reversibility of the inductor, two cases were studied: filling and emptying of channels. The tuning range of the inductance is approximately 107 % at 1.6 GHz, making these devices very suitable as building blocks in many RF applications. 相似文献
8.
The concept of volume averaging is used to theoretically study the mechanisms of mass dispersion, adsorption, and dead-space volume. These mechanisms are important to the understanding of miscible surfactant flooding. After simpiffication based on order-of-magnitude scaling, a linear core model is solved using state variable finite-difference techniques. Mass dispersion and adsorption are shown to be important model parameters while dead-space volume is a rather insensitive model parameter. 相似文献
9.
子午线轮胎出现不久,就采用钢丝带束层代替了纤维带束层,这对于实现子午线轮胎提高使用寿命和改善操纵性能的潜能是必要的。 相似文献
10.
Intelligent Service Robotics - Multi-robot path finding and coordination is one of the key performance-affecting subsystems of the overall robotic order fulfilment process for use in warehouse... 相似文献