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991.
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993.
In this paper, a true-direction flux reconstruction of the second-order quiet direct simulation (QDS-2N) Smith et al. (2009) [3] as an equivalent Euler equation solver, called QDS-N2, is proposed. Because of the true-directional nature of QDS, where volume-to-volume (true-direction) fluxes are computed, as opposed to fluxes at cell interfaces as employed by traditional finite volume schemes, a volumetric reconstruction is required to reach a totally true-direction scheme. The conserved quantities are permitted to vary (according to a polynomial expression) across all simulated dimensions. Prior to the flux computation, QDS particles are introduced using properties based on weighted moments taken over the polynomial reconstruction of the conserved quantity fields. The resulting flux expressions are shown to exactly reproduce the existing second-order extension for a one-dimensional flow, while providing a means for true multi-dimensional reconstruction. The new reconstruction is demonstrated in several verification studies. These include a shock–bubble interaction problem, an Euler-four-shock interaction problem, and the advection of a vortical disturbance. These results are presented, and the increased computation time and the effect of higher-order extension are discussed in this paper. The results show that the proposed multi-dimensional reconstruction provides a significant increase in the accuracy of the solution. We show that, despite the increase in the computational expense, the computational speed of the proposed QDS-N2 method is several times higher than that of the previously proposed QDS-2N scheme for a fixed degree of numerical accuracy, at least, for the test problem of the advection of vertical disturbances. 相似文献
994.
Chinho Lin Ming-Lung Hsu David C. Yen Ping-Jung Hsieh Hua-Ling Tsai Tsung-Hsien Kuo 《Information Systems Frontiers》2013,15(3):497-509
Core capabilities are critical abilities that enhance and sustain an organization’s competitive advantage in extremely competitive environments. In today’s complex and dynamic business environment, companies are often prevented from effectively and efficiently evaluating relevant factors necessary for developing their core capability strategic systems. These systems, with inherent human decision-making processes, should be fully considered when creating a method for determining a firm’s suitable or required core capabilities. It is helpful to implement IT-based group decision support systems (GDSS) with soft computing algorithms to assist managers in determining the appropriate core capabilities for the firm. Therefore, this study develops a holistic group decision support system in which similarity measures, fuzzy set theory, and fuzzy mathematics programming are implemented to facilitate managers in making decisions. Through evaluations done in actual cases, we have found that this system creates a flexible and user-friendly environment that aids top management and other relevant staff members in evaluating all relevant factors related to core capabilities. 相似文献
995.
Abstract In this paper, the salt effect of lithium bromide (LiBr) on the dimethyl formamid (DMF) solution polymerization of acrylonitrile was studied. From the experimental data, we proposed a possible mechanism and derived its rate expression to determine the kinetic parameters for this system. The results show that the values of kv/ktr (1.984~79.365) and kt/k2 tr (3.311×l02~3.156×l05 sec·mole/1) of the DMF‐LiBr solution polymerization of acrylonitrile are larger than those of the DMF‐LiCl solution polymerization of acrylonitrile shown by Bamford and others. These results can be explained by the basicity of salt and the dissociation of polyacrylonitrile in the DMF‐LiBr solution. 相似文献
996.
Chien Y. Su M.C. Tom Kuo Kang F. Liang Chun Y. Lin 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2010,85(12):1604-1615
BACKGROUND: While overall removal of trichloroethylene (TCE) can be estimated from in situ pilot studies of aerobic cometabolism, no quantitative information on the relative importance of the biodegradation and sorption processes is currently available. This paper presents a quantitative method to evaluate the dynamics and the individual removal efficiencies of cometabolic biodegradation and sorption processes using model simulations for in situ aerobic cometabolism. RESULTS: The first‐order rate constant of TCE cometabolism by aerobic toluene‐utilizing bacteria was around 0.2 to 0.3 L mg?1 day?1. The TCE partition coefficient of sorption was determined at 16.4 L kg?1. The sorption process diminished as the sorption capacity of the aquifer solids became saturated. The sustainable TCE removal efficiency due to cometabolic biodegradation for the in situ pilot was determined at 25.8%, 51.8%, and 75.2% for residence times of 0.14 day, 0.57 day, and 1.16 day, respectively, after establishing an indigenous toluene‐degrading consortium. CONCLUSION: The agreement between model simulations and pilot results demonstrates the validity of a model that incorporates fundamental microbial and transport processes of advection, dispersion, and sorption onto the aquifer solids. The mathematical model aids the understanding of both the dynamics and the individual removal efficiencies of sorption and biodegradation processes of in situ bioremediation. Copyright © 2010 Society of Chemical Industry 相似文献
997.
Shou‐Kuo Hsu Yun‐Chin Chung Chen‐Tien Chang Hsien‐Yi Sung 《International Journal of Food Science & Technology》2012,47(9):1872-1881
Three isoforms of peroxidase (POD) were isolated from the sheaths of bamboo shoots by chromatofocusing on Polybuffer exchanger PBE 94. POD‐A was partially purified, and POD‐B and POD‐C were purified and characterised. POD‐A was a basic peroxidase, whereas POD‐B and POD‐C were acidic peroxidases with different isoelectric points. Using o‐phenylenediamine (OPD) as a hydrogen‐donor, the optimum temperatures for function of POD‐B and POD‐C were 55 and 45–55 °C, respectively, while both had the same optimum pH of 4.5. Both isoforms were stable between 30 and 60 °C and between pH 4.5 and 10. The activities of the POD isoforms towards hydrogen‐donors were both pH and concentration dependent. Under optimal conditions, POD‐B and POD‐C catalysed the oxidation of catechol, pyrogallol, and OPD at higher rates than guaiacol, o‐dianisidine and 2, 2’‐azino‐bis‐ (3‐ethylbenzothiazoline‐6‐sulphonic acid). Both isoforms were almost completely inhibited by chemical modification reagent diethyl pyrocarbonate (4.5 mM). 相似文献
998.
999.
Chih‐Hong Lin Kuo‐Tsai Chang 《International Journal of Adaptive Control and Signal Processing》2019,33(5):802-828
Due to air‐gap field harmonic, cogging torque, stator's current time harmonic, and the influence of flux saturation, a six‐phase copper rotor induction motor (SCRIM) drive system has highly nonlinear uncertainties. Thus, the linear control method for the SCRIM drive system is difficult to achieved good performance under the nonlinear uncertainty action. To obtain better control performance, the adaptive backstepping control system using switching function is firstly proposed for controlling the SCRIM drive system to overcome the uncertainty influence. With the proposed control system, the SCRIM drive system holds in robustness to these uncertainties for the tracking of periodic reference trajectories. To enhance the robustness of the SCRIM drive system, the adaptive backstepping control system using adaptive law is proposed for estimating the required lumped uncertainty to reduce chattering phenomenon. When the inertia of the counterweight is varying, this proposed method can perform well in general situations but cannot get a satisfactory performance. The adaptive backstepping control system using mended recurrent Romanovski polynomials neural network with reformed particle swarm optimization (PSO) is thus proposed to estimate the lumped uncertainty and to compensate estimated error for obtaining better control performance. Furthermore, two variable learning rates of the weights in the mended recurrent Romanovski polynomials neural network are adopted by using reformed PSO to speed up parameter's convergence. Finally, some experimental results with comparative control performances are demonstrated, and then, the effectiveness of proposed control system with better control performance is verified for the position tracking of periodic reference inputs. 相似文献
1000.
Microsystem Technologies - Blood separation is an essential first step when performing blood tests for clinical diagnosis purposes. Such tests are increasingly performed using microfluidic systems... 相似文献