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31.
B. Marí K.C. Singh Paula Cembrero-Coca Ishwar Singh Devender Singh Subhash Chand 《Displays》2013,34(4):346-351
Ca (or Sr)TiO3:Eu3+, M (Li+ or Na+ or K+) and CaTiO3:Pr3+, M (Li+ or Na+ or Ag+ or K+ or Gd3+ or La3+) powders were prepared by combustion synthesis method and the samples were further heated to ~1000 °C to improve the crystallinity. The structure and morphology of materials were examined by X-ray diffraction (XRD) and a scanning electron microscopy (SEM). The morphologies of SrTiO3:Eu3+, CaTiO3:Eu3+ or CaTiO3:Pr3+ powders co-doped with other metal ions were very similar. Small and coagulated particles of nearly cubical shapes with small size distribution having smooth and regular surface were formed. Photo-luminescence spectra of CaTiO3:Pr3+ and co-doped either with Li+, Na+, K+, Ag+, La3+ or Gd3+ ions showed red emissions at 613 nm due to the 1D2 → 3H4 transition of Pr3+. The variation of intensity of emission peak with different co-doping follows the order: K+ > Ag+ > Na+ > Li+ > La3+ > Gd3+. The characteristic emissions of CaTiO3:Eu3+ lattices had strong emission at 614 and 620 nm for 5D0 → 7F2 with other weak transitions observed at 580, 592, 654, 705 nm for 5D0 → 7Fn transitions where n = 0, 1, 3, 4 respectively in all host lattices. Photoluminescence intensity in SrTiO3:Eu3+ is more than CaTiO3:Eu3+ lattices. A remarkable increase of photoluminescence intensity (in 5D0 → 7F2 transition) was observed if co-doped with Li+ ions in CaTiO3:Eu3+ and SrTiO3:Eu3+. 相似文献
32.
Chinmay Mallik Shyam Lal Manish Naja Duli Chand S. Venkataramani Hema Joshi 《International journal of remote sensing》2013,34(8):2749-2762
The combustion of fossil fuels (coal and petroleum products) constitutes a source of continuous release of anthropogenic SO2 into the atmosphere. Furthermore, natural sources such as volcanoes can inject large amounts of SO2 directly into the troposphere and sometimes even into the stratosphere. These event-based volcanic eruptions provide solitary opportunities to study the transport and transformation of atmospheric constituents. In this study, we present an episode of high SO2 concentration over northern India as a result of long-range transport from Africa using multiple satellite observations. Monthly averaged column SO2 values over the Indo-Gangetic Plain (IGP) were observed in the range of 0.6–0.9 Dobson units (DU) during November 2008 using observations from the Ozone Monitoring Instrument (OMI). These concentrations were conspicuously higher than the background concentrations (<0.3 DU) observed during 2005–2010 over this region. The columnar SO2 loadings were highest on 6 November over most of the IGP region and even exceeded 6 DU, a factor of 10–20 higher than background levels in some places. These enhanced SO2 levels were not reciprocated in satellite-derived NO2 or CO columns, indicating transport from a non-anthropogenic SO2 source. As most of the local aerosols over the IGP region occur below 3 km, a well-separated layer at 4–5 km was observed from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. Wind fields and back-trajectory analysis revealed a strong flow originating from the Dalaffilla volcanic eruption in Ethiopia during 4–6 November 2008. Although volcanic SO2 plumes have been extensively studied over many parts of Asia, Europe, and the USA, analysis of such events for the IGP region is being reported for the first time in this study. 相似文献
33.
The combined effect of magnetic field and rotation on thermosolutal instability of a compressible fluid in porous medium is considered. The system is found to be stable for (Cp/g)β < 1 where Cp, β, and g stand for specific heat at constant pressure, uniform adverse temperature gradient, and acceleration due to gravity, respectively. The stable solute gradient, magnetic field, and rotation introduce oscillatory modes in the system for (Cp/g)β > 1, which were nonexistent in their absence. For stationary convection, the stable solute gradient and rotation have a stabilizing effect on the system for (Cp/g)β > 1. In the presence of rotation, the magnetic field has a stabilizing (or destabilizing) effect, and the medium permeability has a destabilizing (or stabilizing) effect under certain condition, whereas in the absence of rotation, the magnetic field and rotation have stabilizing and destabilizing effects for (Cp/g)β > 1, respectively, on the system. The sufficient conditions for the existence of overs-lability are obtained. 相似文献
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36.
Harish Kumar Sharma Jaspal Singh Bhavesh Chand Sarkar Barinderjit Singh Monica Premi 《LWT》2012,47(1):208-212
The glucose is considered to affect the quality of the dried egg products; therefore the statistical optimization of desugarization process parameters of Liquid whole egg (LWE) was carried out in this study. The fermentation of Liquid whole egg (LWE) was done using compressed baker’s yeast. A polynomial model was regressed between reducing sugar & desugarization conditions. The coefficient of determination (R2) of 0.998 (P < 0.0001) for the regressed model indicated about the adequacy of the model, which implies the model was significant to predict reducing sugar content at different fermentation conditions. Optimum conditions for complete desugarization of Liquid whole egg (LWE) were found to be time 6.49 h, temperature 28 °C, pH 6.40 and yeast concentration 3.8 g/L and confirmed by conducting actual experiments at these conditions. 相似文献
37.
Samir Saraswati Praveen Kumar Agarwal Satish Chand 《Expert systems with applications》2011,38(6):6916-6925
In SI engines, spark advance (SA) needs to be controlled to get Maximum Brake Torque (MBT) timing. Spark advance can be controlled either by open loop or by closed loop controller. The open loop controller requires extensive testing and calibration of engine, to develop look up tables. In closed loop controller, empirical rules relating variables deduced from cylinder pressure are used. One of such empirical rules is to fix location of peak pressure (LPP) at a desired value of the crank angle. In the present work, a combined neural network and fuzzy logic-based control scheme is designed for SA control to get MBT timing. The fuzzy logic controller is designed to maintain LPP of SI engine close to 16° ATDC. The controller works in conjunction with Recurrent Neural Network model for cylinder pressure identification. LPP is estimated from cylinder pressure curve reconstructed using neural network model and is used as feedback signal to fuzzy logic controller. The simulations have been carried out to test the performance of the combined neural network and fuzzy logic-based control strategy. The simulation results show that the proposed strategy can quite satisfactorily control LPP to its desired value. 相似文献
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39.
The present paper considers a time-dependent queueing model having a finite number of parallel channels each having a different service rate. The probabilities of the exact number of arrivals and departures by a given time and marginal probabilities of the exact number of arrivals are obtained. 相似文献
40.
Shami Abdallah Assi Chadi Habib I. Ali M. A. Ghani N. 《Photonic Network Communications》2003,6(1):25-32
This paper investigates and compares the performance of two GMPLS-based distributed control and management protocols for dynamic lightpath provisioning in future IP networks. The first protocol is a global information-based link state approach that consists of both an integrated RWA algorithm and a signaling algorithm. Two triggering mechanisms for the LSAs update procedures are considered; one is periodic-based and the other is threshold-based. The second protocol is a local-information based fixed alternate link routing approach where the signaling protocol is closely integrated with the RWA protocols. 相似文献