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81.

The energy-efficient deployment of small cells helps to reduce environmental pollution in an ultra-dense network. In contrast, demand for massive connectivity and higher data rate are the promise of the present cellular system and small cell networks. Hence, energy consumption is reduced if base stations are optimally used. One way to improve the energy efficiency is by shutting down the redundant BSs while sustaining the Quality of Service for each user. This paper proposes an efficient cell modeling (ECM) algorithm for small cell formation, and binary particle swarm optimization-based small cell deployment (BPSD) to optimize the deployment of small base stations in the small cell network. The small base stations (s-BSs) exist in two modes: active and sleep which is decided by the proposed algorithm without compromising the network performance. The proposed ECM and BPSD algorithms are implemented and evaluated in MATLAB. The results demonstrate that the proposed approaches improve the energy efficiency and connectivity in the ultra-dense small cell network.

  相似文献   
82.
Objective: The study was aimed to improve the dissolution and bioavailability of developed stable amorphous solid dispersions (SDs) of pioglitazone hydrochloride (PGH), a poorly water-soluble drug.

Significance: Poor aqueous solubility of PGH was overcome by the design of SDs. Level A correlation demonstrated between in vitro release and bioavailability of PGH, suggest its biowaiver potential.

Methods: The effects of semicrystalline copolymers (poloxamer 407 and gelucire 50/13) and methods of preparations on dissolution behavior, in vivo performance, and stability of PGH SDs were investigated. All the SDs were characterized by FTIR, TGA, DSC, XRD, and SEM.

Results: FTIR and TGA showed the compatibility with the polymers. The significant change in melting pattern of the PGH observed in the DSC thermograms supported by XRD patterns & SEM indicated a change from a crystalline to an amorphous state. Gelucire 50/13 was observed to have greater ability to form SDs than poloxamer 407 in solvent evaporation method (SM). Prevention of recrystallization during storage suggested stability of the formulation. Gelucire 50/13 based SD, prepared by SM remarkably increased the dissolution within 15?min (87.27?±?2.25%) and was supported by dissolution parameters (Q15, IDR, RDR, % DE, f1, f2). These SDs showed pH-dependent solubility. In vivo test showed significantly (p?<?.05) higher AUC0–t and Cmax, which were about 3.17 and 4.34 times that of the pure drug respectively.

Conclusion: Gelucire 50/13 was found to be a suitable carrier for SM for preparation of SDs of PGH as evident from increased dissolution and bioavailability.  相似文献   

83.
The fault diagnosis in wireless sensor networks is one of the most important topics in the recent years of research work. The problem of fault diagnosis in wireless sensor network can be resembled with artificial immune system in many different ways. In this paper, a detection algorithm has been proposed to identify faulty sensor nodes using clonal selection principle of artificial immune system, and then the faults are classified into permanent, intermittent, and transient fault using the probabilistic neural network approach. After the actual fault status is detected, the faulty nodes are isolated in the isolation phase. The performance metrics such as detection accuracy, false alarm rate, false‐positive rate, fault classification accuracy, false classification rate, diagnosis latency, and energy consumption are used to evaluate the performance of the proposed algorithm. The simulation results show that the proposed algorithm gives superior results as compared with existing algorithms in terms of the performance metrics. The fault classification performance is measured by fault classification accuracy and false classification rate. It has also seen that the proposed algorithm provides less diagnosis latency and consumes less energy than that of the existing algorithms proposed by Mohapatra et al, Panda et al, and Elhadef et al for wireless sensor network.  相似文献   
84.
This paper deals with the problem of designing a controller for a class of discrete-time nonlinear systems which is represented by discrete-time polynomial fuzzy model. Most of the existing control design methods for discrete-time fuzzy polynomial systems cannot guarantee their Lyapunov function to be a radially unbounded polynomial function, hence the global stability cannot be assured. The proposed control design in this paper guarantees a radially unbounded polynomial Lyapunov functions which ensures global stability. In the proposed design, state feedback structure is considered and non-convexity problem is solved by incorporating an integrator into the controller. Sufficient conditions of stability are derived in terms of polynomial matrix inequalities which are solved via SOSTOOLS in MATLAB. A numerical example is presented to illustrate the effectiveness of the proposed controller.  相似文献   
85.
Temporal variation of ‘surface energy balance’ was quantified on tropical lowland rice for 4 years (2013–2016). High response (10 Hz) eddy covariance system was used to estimate real time data on net radiation (NR), sensible heat (Hs), latent heat (LE), air and soil temperature. Annual, monthly, diurnal as well as phenological crop stage wise variation were analysed. Majority of radiation received from sun was partitioned into latent heat (LE, 44–73%) followed by soil heat (G, 13–42%) and sensible heat (Hs 3–16%) in dry cropping season. This was primarily due to presence of stagnant water in this ecology throughout the cropping period except few days during harvesting. Average Hs was negative in the month of April because of higher evapotranspiration during full grown crop at its reproductive stage as well as stagnant water in field. LE was the major contributor of energy balance and consistently increased from active tillering to grain filling stages then gradually decreased in harvesting. Hs contributing more at the initial stages of rice. Diurnal variation showed maximum Hs during 12:00 to 13:00 hours, whereas, highest LE and G were noticed during 13:00 and 11:30–12:00 hours, respectively. LE and G regressed well than Hs with air temperature and NR.  相似文献   
86.
Wireless Personal Communications - Worldwide interoperability for Microwave Access (WiMAX) is an advanced wireless broadband access technology for delivering high speed voice, video and multimedia...  相似文献   
87.

Every year thousands of urban and industrial fires occur, which leads to the destruction of infrastructure, buildings, and loss of lives. One of the reasons behind this is the delayed transmission of information to the fire station and the nearer hospitals for ambulance service as the transmission of information is dependent on observer at the location where the fire is caught and cellular network. This paper proposed an automated routing protocol for the urban vehicular ad-hoc network to send the information from the location where the fire is caught to the nearest fire stations and hospitals with optimum service time. This transmission of information involves Road Side Unit (RSU) at the junction and the vehicles present in the transmission path. Selection of route to transmit faulty vehicle information from the RSU to the required faulty vehicle is based on a parameter called path value. The computation of path value is done by the attributes such as expected End To End (E2E) delay, the shortest distance to destination, the density of vehicle between the junctions, and attenuation. From the current junction, the selection of the next junction is based on minimum path value. The proposed routing protocol considers the performance parameters such as E2E delay, total service time (TST), number of network fragments or network gaps, number of hops, and attenuation for the propagation path for the evaluation of the proposed methodology. The proposed routing algorithm is implemented through OmNet++ and SUMO. Results obtained for the proposed routing protocol is compared with three existing VANET protocols (GSR, A-STAR, and ARP) in terms of End To End delay, number of hops, number of vehicular gaps, and Total Service Time (TST).

  相似文献   
88.

Most of the researches on error rate analysis of direct sequence spread spectrum (DSSS-CDMA) systems assume that the synchronization is perfect. However, in practice, the synchronization is often imperfect due to various effects of channel parameters such as noise and fading. The degree of imperfection further increases due to jamming attacks. The present study, therefore, derives new expressions to compute the probability of error in DSSS-CDMA systems under imperfect synchronisation. It is assumed that the channel is wideband and is subjected to various jamming attacks. A new parameter, called as probability of successful synchronization, was introduced which includes the effects of both the probability of false alarm and detection under fast and slow jammers. Monte Carlo simulations were conducted in MATLAB to establish the validity of the derived mathematical expressions.

  相似文献   
89.
A range of carbon coatings with different hardness and modulus was compared for wear and frictional behaviours using one-side-carbon-coated Ti-6Al-4V alloy couples tested under conditions of combined impact and sliding contact. Carbon films with hardness over 10 GPa were found to cause far greater volume loss of the uncoated counterpart, and the volume loss was approximately proportional to the extent of hardness deviation above 10 GPa. The coefficient of friction was shown to correlate positively with coating hardness. The tendency of a softer coating to possess a greater sp2 or graphite-like content provides more effective solid lubrication in a wet environment, hence minimising both wear and friction. The corresponding low film modulus also provides an optimal structural integrity of the composite system by minimising the elastic modulus mismatch between the film and the underlying substrate.  相似文献   
90.
The separation of Y(III) from Eu(III) using a hollow fiber-supported liquid membrane with 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (EHPNA) as an extractant was studied. The effects of HCl and metal concentrations in the feed solution, the EHPNA concentration in the membrane, and the HCl concentration in the stripping solution on the initial fluxes of the two metals and the separation factor were investigated. The optimum conditions for selective recovery of Y(III) from an equimolar solution of Y(III) and Eu(III) chlorides (0.001?mol?L?1 each) were as follows: HCl concentration in the feed solution, 0.1?mol?L?1; EHPNA dimer concentration in the organic phase in the membrane, 0.1?mol?L?1; and HCl concentration in the stripping solution, 4?mol?L?1. Under these conditions, complete Y(III) extraction was achieved after 1 ks of operation, and the Y(III) purity in the stripping solution was 84%.  相似文献   
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