全文获取类型
收费全文 | 606篇 |
免费 | 9篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 4篇 |
综合类 | 3篇 |
化学工业 | 69篇 |
金属工艺 | 4篇 |
机械仪表 | 16篇 |
建筑科学 | 25篇 |
能源动力 | 4篇 |
轻工业 | 7篇 |
水利工程 | 1篇 |
石油天然气 | 6篇 |
武器工业 | 1篇 |
无线电 | 97篇 |
一般工业技术 | 81篇 |
冶金工业 | 211篇 |
自动化技术 | 91篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2019年 | 2篇 |
2018年 | 8篇 |
2017年 | 8篇 |
2016年 | 8篇 |
2015年 | 2篇 |
2014年 | 12篇 |
2013年 | 40篇 |
2012年 | 9篇 |
2011年 | 35篇 |
2010年 | 30篇 |
2009年 | 27篇 |
2008年 | 25篇 |
2007年 | 25篇 |
2006年 | 18篇 |
2005年 | 15篇 |
2004年 | 13篇 |
2003年 | 18篇 |
2002年 | 17篇 |
2001年 | 9篇 |
2000年 | 17篇 |
1999年 | 21篇 |
1998年 | 50篇 |
1997年 | 33篇 |
1996年 | 40篇 |
1995年 | 23篇 |
1994年 | 21篇 |
1993年 | 15篇 |
1992年 | 9篇 |
1991年 | 11篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 11篇 |
1987年 | 7篇 |
1986年 | 3篇 |
1985年 | 3篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有620条查询结果,搜索用时 421 毫秒
11.
Physical properties of activated carbons prepared from pinewood at different activation times (0.5, 1.5, 2.7, and 4.0 h) in steam at 900 °C were studied. The adsorption equilibria and kinetics of three dyes and three phenols (phenol, 3-chlorophenol, and o-cresol) from aqueous solutions on such carbons were then examined at 30 °C. The adsorption isotherms of phenols could be well fitted by the Freundlich equation, and those of dyes were adequately described by the Langmuir-Freundlich equation. The effect of microporosity of the carbons on adsorption capacity was explored. Four simplified kinetic models including pseudo-first-order equation, pseudo-second-order equation, intraparticle diffusion model, and the Elovich equation were selected to follow the adsorption processes. The adsorption of all six adsorbates could be best described by the Elovich equation. The kinetic parameters of this best-fit model were calculated and discussed. 相似文献
12.
Three types of pegylated amphiphilic copolymers of poly(δ‐valerolactone) (PVL) were copolymerized with methoxy poly(ethylene glycol) (MePEG) and poly(ethylene glycol) (PEG4000 and PEG10,000), respectively. Pegylation of PVL allowed copolymers possessing amphiphilic property and efficiently self‐assembled to form micelles with a low critical micelle concentration (CMC) in the range of 10?7–10?8M. The average molecular weight of copolymers was in the range of 10,000–20,000 Da, and the polydispersity of copolymers was about 1.7–1.8. Higher mobility of low molecular weight PEG (i.e., MePEG and PEG4000) than high molecular weight PEG10,000 allowed valerolactone ring opening more efficient in terms of PVL/MePEG and PVL/PEG4000 copolymers possessing longer chain length in hydrophobic domain. Pegylated PVL with low CMC and triblock structure was preferred to encapsulate drug during micelle formation. Although all of these amphiphilic copolymers exhibited controlled release character, the micelles formed by triblock copolymer possessed a more stable core‐shell conformation than that by diblock copolymer, and resulted in the release of drug from triblock micelles slower than that from diblock micelles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 1836–1841, 2006 相似文献
13.
Su‐Hsia Lin Hsiang‐Chien Kao Shih‐Hung Huang Ruey‐Shin Juang 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2002,77(2):168-174
The equilibrium and kinetics of solvent extraction of Cu2+ from aqueous solutions containing equimolar EDTA with Aliquat 336 in n‐decanol and kerosene at 298 K were investigated. The concentrations of Cu2+ (8–50 mol m?3), Cl? (5–60 mol m?3), and Aliquat 336 (20–100 mol m?3) were varied. A semi‐empirical model with three parameters was proposed to describe the equilibrium behavior, in which the non‐idealities in both aqueous and organic phases were considered. Over the ranges studied, the model agreed reasonably well with the experimental data (standard deviation, 15%). The forward and backward reaction rate constants were determined as (5.31 ± 0.16)×10?6 m9/4 mol?3/4 s?1 and (2.62 ± 0.09)×10?7 s?1, respectively, at 298 K. An interfacial reaction mechanism was proposed, which revealed that the reaction between the chelated anions and trimeric amine molecules at the interface was rate limiting. The derived rate laws were consistent with the experimental results. © 2002 Society of Chemical Industry 相似文献
14.
Sez Atamturktur Zhifeng Liu Scott Cogan Hsein Juang 《Structural and Multidisciplinary Optimization》2015,51(3):659-671
Traditionally, model calibration is formulated as a single objective problem, where fidelity to measurements is maximized by adjusting model parameters. In such a formulation however, the model with best fidelity merely represents an optimum compromise between various forms of errors and uncertainties and thus, multiple calibrated models can be found to demonstrate comparable fidelity producing non-unique solutions. To alleviate this problem, the authors formulate model calibration as a multi-objective problem with two distinct objectives: fidelity and robustness. Herein, robustness is defined as the maximum allowable uncertainty in calibrating model parameters with which the model continues to yield acceptable agreement with measurements. The proposed approach is demonstrated through the calibration of a finite element model of a steel moment resisting frame. 相似文献
15.
Design of variable structure control for fuzzy nonlinear systems 总被引:1,自引:0,他引:1
In this paper, the variable structure control problem is presented for Takagi–Sugeno fuzzy systems with uncertainties and external disturbances. The sliding surfaces for the T–S fuzzy system are proposed by using a Lyapunov function and a fuzzy Lyapunov function, respectively. And we design the variable structure controllers such that the global T–S fuzzy system confined on the sliding surfaces is asymptotically stable. Two examples are given to illustrate the effectiveness of our proposed methods. 相似文献
16.
Chia-Feng Juang Ren-Bo Huang Yang-Yin Lin 《Fuzzy Systems, IEEE Transactions on》2009,17(5):1092-1105
This paper proposes a recurrent self-evolving interval type-2 fuzzy neural network (RSEIT2FNN) for dynamic system processing. An RSEIT2FNN incorporates type-2 fuzzy sets in a recurrent neural fuzzy system in order to increase the noise resistance of a system. The antecedent parts in each recurrent fuzzy rule in the RSEIT2FNN are interval type-2 fuzzy sets, and the consequent part is of the Takagi-Sugeno-Kang (TSK) type with interval weights. The antecedent part of RSEIT2FNN forms a local internal feedback loop by feeding the rule firing strength of each rule back to itself. The TSK-type consequent part is a linear model of exogenous inputs. The RSEIT2FNN initially contains no rules; all rules are learned online via structure and parameter learning. The structure learning uses online type-2 fuzzy clustering. For the parameter learning, the consequent part parameters are tuned by a rule-ordered Kalman filter algorithm to improve learning performance. The antecedent type-2 fuzzy sets and internal feedback loop weights are learned by a gradient descent algorithm. The RSEIT2FNN is applied to simulations of dynamic system identifications and chaotic signal prediction under both noise-free and noisy conditions. Comparisons with type-1 recurrent fuzzy neural networks validate the performance of the RSEIT2FNN. 相似文献
17.
A recent trend among physicians is the categorisation of lung scans as normal [excludes pulmonary embolism (PE)], high probability (confirms PE) and non-diagnostic (no judgement on PE risk). The low probability scan is therefore being eliminated as a functional category. This occasional survey contends that such an approach is misguided. Correction of the original PIOPED data with certain assumptions provides a more reproducible, albeit restricted, low probability scan category which excludes PE in 97% of cases in the low pre-test clinical category. Patients with a low probability scan with risk factors for PE (i.e. medium clinical risk) will require further investigation. More important, the very low probability scan category excludes PE in 98% of patients with low and more than 92% of patients with medium pre-test clinical likelihood. The demise of "low probability" is premature. 相似文献
18.
Yi-Bo Wu Juang Wang Chun-Ping Yan Sheng-Ping Mao Cong-Chun Zhang Hong Wang Gui-Fu Ding 《Microsystem Technologies》2010,16(11):1869-1879
Bistable micro mechanisms are gaining great attention in MEMS applications. This paper presents the mechanical modeling and
experimental characterization of a bistable torsion/cantilever micro latching mechanism for performing low power bistable
relay applications. The bistable micro mechanism consists of two cantilevers which form symmetrical rocker levers. The free–free
cantilever is suspended by a diamond skeleton which in turn is attached to a torsion cantilever. A permanent magnet is placed
beside for holding the closed state with a permalloy soft magnetic circuit. The special diamond support is designed to enhance
the stiffness of the overhang beams. In order to deduce the spring stiffness of system, a mechanical modeling of the leveraged
torsion/cantilever system was performed by Castigliano’s theorem. Meanwhile, the magnetostatic latching force was also deduced
by the Maxwell electromagnetism theory. Then the device has been prepared by a laminated copper sacrificial layer process.
This process can facilitate the fabrication complexities of traditional magnetic device with coil structures. Finally, mechanical
performance was characterized by an atomic force microscopy, combined with finite element simulation using ANSYS™ package and analysis model as well. Two stable states of the micro mechanism were hold successfully with no power consumption
by interferoscope profilometry of WYKO optical profiling system. 相似文献
19.
Wen-Shenq Juang Author Vitae Jing-Lin Wu Author Vitae 《Computers & Electrical Engineering》2009,35(1):33-40
Recently, Parks et al. proposed an authentication and key agreement protocol for low-power PDAs in public wireless LANs using two factors including a password and a token, e.g. a smart card. They claimed that their proposed scheme provided mutual authentication, identity privacy, half-forward secrecy and low computation cost for a client including just one symmetric key encryption and five hash operations. In this paper, we point out that Park et al.’s protocol is vulnerable to the dictionary attack upon identity privacy. We propose two schemes with mutual authentication, half-forward secrecy, lower computation cost and less exchanged messages than Park et al.’s protocol. In additional to these properties, identity privacy, which is not satisfied by Park et al.’s protocol, is also provided by our second scheme. 相似文献
20.
Jieh-Ren Chang Hung-Chi Juang You-Shyang Chen Cheng-Ming Chang 《Multimedia Tools and Applications》2017,76(18):18339-18359
Mining web facial images on the internet has become as a profitable and important paradigm towards auto face annotation technique. The unsupervised label refinement (ULR) is an effective method that can fix weakly labeled facial images data which are collected from the internet and included some images with wrong label. In order to improve the correction accuracy of ULR, particle swarm optimization (PSO) and binary particle swarm optimization (BPSO) are used for solving binary constraint optimization task in this study. A novel method named safe binary particle swam optimization (SBPSO) is also proposed to improve BPSO which has the probability over range problem for using the ULR. In addition, SBPSO is also employed for an enhanced ULR (EULR) objective function which is created by modifying the original formula of ULR to improve the accuracy of labeled facial image. An experimental database is queried from IMDb website which collected the actors who were bored in 1950 to 1990. Some error flags are randomly added in the database for the correction tests by different methods. The results showed that the SBPSO Algorithm for the EULR in automatic face annotation have the better label correction rate and convergence effect. 相似文献