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991.
A validation study using the National Renewable Energy Laboratory (NREL) Phase VI wind turbine is presented. The aerodynamics simulations are performed using the finite element arbitrary Lagrangian–Eulerian–variational multiscale formulation augmented with weakly enforced essential boundary conditions. In all cases, the rotor is assumed to be rigid and its rotation is prescribed. The rotor‐only simulations are performed for a wide range of wind conditions, and the computational results compare favorably with the experimental findings in all cases. The sliding‐interface method is adopted for the simulation of the full wind turbine configuration. The full‐wind‐turbine simulations capture the blade–tower interaction effect, and the results of these simulations are also in good agreement with the experimental data. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
992.
Chih‐Yu Chang Lijian Zuo Hin‐Lap Yip Yongxi Li Chang‐Zhi Li Chain‐Shu Hsu Yen‐Ju Cheng Hongzheng Chen Alex K.‐Y. Jen 《Advanced functional materials》2013,23(40):5084-5090
The versatility of a fluoro‐containing low band‐gap polymer, poly[2,6‐(4,4‐bis(2‐ethylhexyl)‐4H‐cyclopenta[2,1‐b;3,4‐b’]dithiophene)‐alt‐4,7‐(5‐fluoro‐2,1,3‐benzothia‐diazole)] (PCPDTFBT) in organic photovoltaics (OPVs) applications is demonstrated. High boiling point 1,3,5‐trichlorobenzene (TCB) is used as a solvent to manipulate PCPDTFBT:[6,6]‐phenyl‐C71‐butyric acid methyl ester (PC71BM) active layer morphology to obtain high‐performance single‐junction devices. It promotes the crystallization of PCPDTFBT polymer, thus improving the charge‐transport properties of the active layer. By combining the morphological manipulation with interfacial optimization and device engineering, the single‐junction device exhibits both good air stability and high power‐conversion efficiency (PCE, of 6.6%). This represents one of the highest PCE values for cyclopenta[2,1‐b;3,4‐b’]dithiophene (CPDT)‐based OPVs. This polymer is also utilized for constructing semitransparent solar cells and double‐junction tandem solar cells to demonstrate high PCEs of 5.0% and 8.2%, respectively. 相似文献
993.
The effects of dimerumic acid (DMA) on apoptosis prevention and insulin production in the glucose metabolite methylglyoxal (MG)-treated pancreatic RINm5F cells were evaluated. MG was found to induce apoptotic signal molecules mediated by oxidative stress in RINm5F cells, including caspase-3 and caspas-9, resulting in cell death and decreasing insulin production. In addition, DMA elevated insulin synthesis via up-regulating mammalian homologue of avian MafA/L-Maf (Maf-A) and pancreatic-duodenal homeobox-1 (PDX-1) and inhibited MG-mediated CCAAT/enhancer binding proteins-β (C/EBPβ) expression, which is a negative regulator for insulin production. Nuclear factor-erythroid2-related factor 2 (Nrf2) is essential for antioxidant responsive element (ARE)-mediated induction. Results indicated that nuclear translocation of Nrf2 was promoted by DMA in MG-treated RINm5F cells to increase heme oxygenase-1 (HO-1) and glutamate-cysteine ligase (GCL) expressions. We confirmed that DMA protected PDX-1, Maf-A, and insulin production against MG-induced oxidative stress mediating by Nrf2 in Nrf2-knockdown RINm5F cells. These results suggest that DMA exerts antioxidative ability to attenuate MG-induced pancreatic cell damage and elevates insulin level to improve diabetes. 相似文献
994.
995.
Development of a Quantitative Multi-Mycotoxin Method in Rice, Maize, Wheat and Peanut Using UPLC-MS/MS 总被引:2,自引:1,他引:1
Yu Y. Tang Hsu Y. Lin Ying C. Chen Wei T. Su Si C. Wang Lih C. Chiueh Yang C. Shin 《Food Analytical Methods》2013,6(3):727-736
Mycotoxins are secondary metabolites produced by fungi, such as Fusarium, Penicillium, and Aspergillus, which are toxic to humans with high risk factors and pose a significant threat to human health. This study was focused mostly on well-known mycotoxins, such as aflatoxins (AFB1, AFB2, AFG1 and AFG2), fumonisin (FB1, FB2), deoxynivalenol (DON), zearalenone (ZON), ochratoxin A, T-2 and HT-2, in grains. The multi-mycotoxin methods developed in this study utilise an analysis of mycotoxin through liquid chromatography tandem mass spectrometry (LC-MS/MS), which can significantly improve sample analysis efficiency. The Myco6in1? immunoaffinity column was used for purification to reduce interference from the substrate. Gradient separation to obtain the best peak shift was conducted using solvent with 0.1 % formic acid in deionised water and methanol, and gradient separation was performed on an ACQUITY BEH C18 column chromatograph. The recovery rate test for each toxin using substrates such as rice, peanut, wheat and maize mostly indicated good average recovery rates between 70 % and 120 % and the coefficient of variation mostly under 15 %. The limits of quantification (LOQ) identified by this method are less than 5 ng/g in most toxins, except for 20 ng/g in FB1and FB2. This method can rapidly and simultaneously analyse 11 mycotoxins in 9 min. It can be applied for the practical examination of mycotoxins in food to protect public health. 相似文献
996.
This paper presents two low power UWB LNAs with common source topology. The power reduction is achieved by the current-reused technique. The gain and noise enhancement of the proposed circuit is based on an output buffer which is used by a common source amplifier with shunt–shunt feedback. Chip1 is an adopted T-match input network of 50 Ω matching in the required band. Measurements show that the S11 and S22 are less than −10 dB, and the maximum amplifier gain S21 gives 9.7 dB, and the noise figure is 4.2 dB, the IIP3 is −8.5 dBm, and the power consumption is 11 mW from 1.1 V supply voltage. The input matching of chip2 is adopted from a LC high pass filter and source degenerated inductor. The output buffer with the RC-feedback topology can improve the gain, increase the IIP3, restrain the noise, improve the noise figure and decrease the DC power dissipation. Measurements show 13.2 dB of power gain, 3.33 dB of noise figure, and the IIP3 is −3.3 dBm. It consumes 9.3 mW from 1.5 V supply voltage. These two chips are implemented in a 0.18 μm TSMC CMOS process. 相似文献
997.
Shia-Chung Chen Hai-Mei Li Pe-Ming Hsu Hsin-Shu Peng 《Polymer-Plastics Technology and Engineering》2013,52(3):276-281
This study explores how ultra high-speed processing parameters affect the melt flow length and tensile strength of thin-wall injection molded parts. A spiral shaped mold with a specimen thickness of 0.4 mm and a width of 6 mm was first constructed to test the melt flow length as an index of process capability for ultra high-speed injection molding. It was observed that the flow length increases with increasing injection speed. High-density polyethylene (HDPE) tensile test specimens with different thicknesses (0.6 mm and 2 mm) were also molded for tensile tests. Both single gate and double gates were used to form parts without and with weldlines. Injection molding trials were executed by systematically adjusting related parameters setting including mold temperature, melt temperature, and injection speed. The parts’ tensile strengths were measured experimentally. It was found that tensile strengths of 0.6 mm thick parts both with and without weldlines were higher than those of 2 mm thick parts. The tensile strength of 0.6 mm thick specimens increases with increasing mold temperature, melt temperature and injection speed, whereas tensile strength in 2 mm thick specimens was only weakly dependent on the corresponding processing parameters. Furthermore, 0.6 mm thick specimens with weldlines had tensile strengths lowered about 9.6% compared to parts without weldlines. For 2 mm thick part the corresponding reduction is 4.3%. 相似文献
998.
Abstract The basic mechanism for an one transistor memory device has been studied. Many ferroelectric materials such PbZrxTi1?xO3 (PZT), SrBi2Ta2O9 (SBT), Pb5Ge3O11 (PGO) etc. were analyzed for this application. Because of its low remanent polarization and low dielectric constant, the c-oriented Pb5Ge3O11 thin film was selected for one-transistor memory applications. Pb5Ge3O11 thin films have been prepared using MOCVD and RTP (Rapid Thermal Process) post-annealing. Lead bis-tetramethylheptadione [Pb(thd)2] and germanium ethoxide [Ge(OC2H5)4] were used as the precursors. The Pb5Ge3O11thin films were deposited onto Ir/Ti/SiO2/Si wafers to measure their compositions, phase formation, microstructure and ferroelectric properties. The extremely highly c-oriented Pb5Ge3O11 thin films showed good ferroelectric and electrical properties. A 300 nm thick PGO thin film exhibited a square and saturated hysteresis loop with 2Pr of 3.98 μC/cm2, 2Ec of 128 KV/cm at an applied voltage 5V, leakage current of 5.1×10?7 A/cm2 at 100 KV/cm, and dielectric constant of close to 36. The c-axis oriented Pb5Ge3O11 thin film also exhibited very good retention properties. The experimental results showed that a Pb5Ge3O11 MFMOS gate stack is suitable for one-transistor memory applications. 相似文献
999.
A mixed lubrication/friction model for extrusion process is developed in the present research. The model combines a rigid-plasticity finite element code to simulate the interface condition between the tooling and workpiece in the extrusion operation. The influence of surface roughness on lubricant flow is treated by using the average Reynolds equation. The active lubrication regime and appropriate friction factor were determined from the current local values of interface variables such as mean lubricant film thickness and workpiece and tooling roughness, in addition to the more traditional external variables such as interface pressure, node sliding velocity and strain rate of the workpiece. Numerical results using the coupled code include friction stress and normal pressure under different lubrication conditions are compared with experimental investigation. The discrepancy is very small and the proposed model proved to be very efficient in predicting interface friction condition in the extrusion processes. 相似文献
1000.
A ball-on-three-flat (BTF) wear tester was used to investigate the boundary lubricating characteristics of oxygenates on a commercial silicon nitride. A wide variety of oxygen-containing compounds were tested neat and/or at 1% by weight in a paraffin oil. Compounds containing hydroxyl functional groups were more effective compared to a base case of neat paraffin oil. Decreases of up to 58% in friction coefficient, and 95% in wear were obtained. In most cases, films were observed in and around the wear scar, suggesting chemical reactions had taken place in the contact. Additional wear tests, conducted using neat shorter-chain linear primary alcohols, i.e., 6–10 carbons, demonstrated boundary lubrication protection, with longer chain length providing better antiwear performance. A study of several C8 compounds with specific oxygen-containing functional groups (primary alcohol, secondary alcohols, acid, aldehyde, and ketone) demonstrated that the primary alcohol had the strongest boundary lubricating effect. Varying the amount of water in the alcohols had little effect on friction and wear, suggesting that the boundary lubrication effects observed were not merely due to dissolved water in these fluids, but some characteristic chemical interaction with the hydroxyl functional group of the alcohols and acids. 相似文献