全文获取类型
收费全文 | 1347篇 |
免费 | 67篇 |
国内免费 | 2篇 |
专业分类
电工技术 | 41篇 |
化学工业 | 397篇 |
金属工艺 | 12篇 |
机械仪表 | 30篇 |
建筑科学 | 41篇 |
矿业工程 | 3篇 |
能源动力 | 74篇 |
轻工业 | 154篇 |
石油天然气 | 2篇 |
无线电 | 111篇 |
一般工业技术 | 292篇 |
冶金工业 | 33篇 |
原子能技术 | 10篇 |
自动化技术 | 216篇 |
出版年
2023年 | 10篇 |
2022年 | 46篇 |
2021年 | 85篇 |
2020年 | 37篇 |
2019年 | 37篇 |
2018年 | 46篇 |
2017年 | 27篇 |
2016年 | 48篇 |
2015年 | 47篇 |
2014年 | 53篇 |
2013年 | 110篇 |
2012年 | 91篇 |
2011年 | 105篇 |
2010年 | 94篇 |
2009年 | 63篇 |
2008年 | 71篇 |
2007年 | 53篇 |
2006年 | 56篇 |
2005年 | 43篇 |
2004年 | 43篇 |
2003年 | 32篇 |
2002年 | 35篇 |
2001年 | 14篇 |
2000年 | 20篇 |
1999年 | 15篇 |
1998年 | 23篇 |
1997年 | 14篇 |
1996年 | 13篇 |
1995年 | 15篇 |
1994年 | 9篇 |
1993年 | 10篇 |
1992年 | 8篇 |
1991年 | 7篇 |
1990年 | 3篇 |
1989年 | 4篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1976年 | 1篇 |
1975年 | 1篇 |
1973年 | 1篇 |
1972年 | 3篇 |
1965年 | 1篇 |
排序方式: 共有1416条查询结果,搜索用时 15 毫秒
161.
The article presents the inverse dynamics model of a novel translating parallel machine and proposes the structure of a force controller for the execution of tasks characterised by interaction with the environment. The task space model of machine’s dynamics is obtained in an efficient and compact form by means of the principle of virtual work. A virtual prototyping environment has been set up to test by computer simulation the potential of such kinematic architecture: the resulting dynamics is rather poor, mainly due to the high moving masses, but it is shown that hybrid position/force control schemes should be able to provide good performances, including the case of rather difficult operations, such as the peg-in-hole assembly. 相似文献
162.
Simone Orcioni Giorgio Biagetti Massimo Conti 《Analog Integrated Circuits and Signal Processing》2004,38(2-3):215-231
A mixed analog-digital fuzzy logic inference processor chip, designed in a 0.35-μm CMOS technology, is presented. The analog fuzzy engine is based on a novel current-mode CMOS circuit used for the implementation of fuzzy partition membership functions. The architecture consists of a 3 inputs—1 output analog fuzzy engine, internal digital registers to store the parameters of the fuzzy controller, and a digital subsystem that allows the programmability of the fuzzy controller via an I 2 C interface. The architecture, circuits, and some Cadence Spectre simulations are presented. 相似文献
163.
Massimo La Deda Mauro Ghedini Iolinda Aiello Irene De Franco 《Inorganic chemistry communications》2004,7(12):1273-1276
This communication reports the synthesis of polymetallic species formed by a zinc-tetraphenolporphyrinate core (ZnTPP(OH)4, 1) and peripheral gallium-quinaldinate fragments. The photophysical analysis of 1 and of the model compound , R, shows an appreciable overlap between the absorption spectra of 1 and the emission spectra of R, suggesting the presence of a donor–acceptor energy-transfer process. Contrarily, the obtained results indicated that energy transfer does not occur, hence these polymetallic complexes work as double emitting species, for which the colour of luminescence depends on the excitation energy. 相似文献
164.
A set of quantitative data about signal processing effects on the evaluation of amplitude, duration, and peak-velocity of single saccadic eye movements, as well as on the evaluation of the coefficients of amplitude-peak velocity and amplitude-duration characteristics of a family of saccades, is given. The following aspects of signal processing are theoretically discussed, experimentally supported, and summarized by normative graphs: 1) the analog low-pass filtering applied to the recorded eye movement; 2) its sampling and digitization; 3) the low-pass filtering applied to the digitized signal; 4) the algorithm used to compute the eye velocity; 5) the criteria adopted to determine the beginning and the ending points of the saccades; and 6) the laws used to fit the saccadic characteristics. According to the theoretical and experimental results obtained, some general operating rules and optimal setups for each of the most common experimental situations are proposed, with the aim of standardizing saccade analysis for both researchers and clinicians. 相似文献
165.
Massimo Corcione 《International Journal of Heat and Mass Transfer》2005,48(17):3660-3673
Steady laminar free convection from flat vertical arrays of equally-spaced, horizontal isothermal cylinders set in free air, is studied numerically. A specifically developed computer-code based on the SIMPLE-C algorithm is used for the solution of the mass, momentum and energy transfer governing equations. Simulations are performed for arrays of 2-6 circular cylinders, for center-to-center separation distances from 2 up to more than 50 cylinder-diameters, and for values of the Rayleigh number based on the cylinder-diameter in the range between 5 × 102 and 5 × 105. It is found that the heat transfer rate at the bottom cylinder remains the same as a single cylinder. In contrast, the downstream cylinders may exhibit either enhanced or reduced Nusselt numbers depending on their location in the array and on the geometry of the array. Heat transfer dimensionless correlating equations are proposed both for any individual cylinder in the array and for the whole tube-array. New correlation-equations for the calculation of the heat transfer rate from a single cylinder to the surrounding air are also proposed and compared to those available in the open literature. 相似文献
166.
Lead and the Pb-Bi eutectic (Pb 55.9 at.%) have been modeled by a n-body potential derived from a second moment approximation of a tight binding Hamiltonian. The thermal behavior of the two systems in the liquid phase has been reproduced and relevant structural parameters have been evaluated and compared with experimental data. The diffusion coefficients and the activation energy for diffusion have been also evaluated. 相似文献
167.
Pietro Benetti Massimo Genoni Alessandra Tomaselli 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》1988,270(2-3):411-415
The influence of photon peak arrival in the laser-optical fibers timing system of a large array of plastic scintillators has been studied for different types of photomultipliers. The obtained results, helpful in properly designing the system are presented and discussed. 相似文献
168.
The problem of isothermal diffusion-reaction in a slab catalyst with bimolecular Langmuir—Hinshelwood kinetics is studied. Analytic solutions for the concentration profile and the catalytic effectiveness factor are reported for the full range of Thiele modulus values, in the limit of large adsorption inhibition constant. In this limit, connections with negative first-order kinetics are shown, and rather good explicit estimates of the region of multiple steady states are provided. Comparisons with numerical calculations are also made. 相似文献
169.
Hydrolysis of tannery wastes to protein meal for animal feedstuffs: A process and product evaluation
Enzo Montoneri Giovanni Rizzi Arnaldo Rizzi Archimede Mordenti Adriano Bauli Massimo Riolfatti Laura Pellegrini 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(1):91-99
Hydrolysis of protein solid wastes from tanneries to yield protein meal for animal nutrition has been performed in a pilot assembly designed to process 400 kg h?1 of disposal material under optimum energy consumption and product yield conditions. Evaluation of the significance of amino acid degradation caused by the process, in relation to the product cost and quality in animal nutrition, was the purpose. A nutrition bioassay was carried out to study the incidence of dietary substitution of the above protein meal for soybean meal on growth performance by early weaned piglets. The results show that degradation of serine, proline, arginine and threonine occurs during collagen hydrolysis, and that only the threonine concentration in the product falls below the dietary requirement. However, integration of protein meal diets with the necessary amino acid content may be accomplished cheaply. Compared with other vegetable and animal commercial protein meals, the cost of the product obtained from tanned hides appears competitive. Processing of other tannery disposal material is not recommended, due to the low protein content of the starting material. 相似文献
170.
It is well known that mathematical models which simulate comminution processes represent a useful tool in several fields of academic and industrial research, with particular emphasis on nano-material and pharmaceutical production. In the present work a mathematical model which is able to quantitatively describe comminution processes in a ball milling system (i.e., Spex-Mixer/Mill) has been developed. The proposed approach takes into account three different contributions: dynamics of the vial, dynamics of spheres motion and simulation of the comminution process. The vial dynamics has been modelled by taking advantage of an appropriate roto-translation matrix. Model results have been successfully compared with literature experimental data. The spheres motion within the Spex Mixer/Mill has been simulated using a 3D dynamic model based on classical mechanics as well as the so-called discrete element method, which is widely adopted to quantitatively describe multi-body collision behaviour. In particular, existing models of impact with dissipation as well as the classical Hertz impact theory have been taken into account. This part of the global model allows one to obtain, for different operating conditions, the impact specific energy and impact velocity as a function of time. The latter ones represent input parameters for the simulation of comminution processes that is performed through suitable population balances, where different breakage functions as well as appropriate breakage probabilities have been considered. Model results are reported in terms of granulometric distribution of powders within the mixer-mill as a function of time, minimal grain size obtainable and time needed to complete the comminution process for various operating conditions (i.e., mill frequency and charge ratio). 相似文献