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41.
Containerless tube extrusion has been investigated with commerically pure titanium at room temperature and a strain rate of 0.07 s-1 using 20 conical dies of five different strains and four different angles with MoS2 lubricant. Theoretical punch pressures have been calculated using appropriate equations from slab analysis of the process and compared with experimentally determined punch pressures. It is found that there exists an optimum angle at which the punch pressure is the least at a given strain. 相似文献
42.
Yugal Kishore Mohanta Sameer Kumar Singdevsachan Umesh Kumar Parida Sujogya Kumar Panda Tapan Kumar Mohanta Hanhong Bae 《IET nanobiotechnology / IET》2016,10(4):184
In the present study, green synthesis and cost effective approach of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers.) Pat. from Similipal Biosphere Reserve, Odisha, India is reported. The biosynthesised AgNPs were characterised using UV‐visible spectroscopy, particle analyser and scanning electron microscopy studies. It was found by dynamic light scattering analysis, that the average size and charges of the AgNPs were 133.0 ± 0.361 nm and −6.01 ± 5.30 mV, respectively. Moreover, the Fourier transform infrared study was also conducted to identify the biomolecules or functional groups responsible for the reduction of Ag and stabilisation of the AgNPs. The potential biomedical application with reference to antimicrobial activity of the synthesised AgNPs was investigated against some pathogenic microorganisms viz. Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus and Shigella flexneri.Inspec keywords: antibacterial activity, biomedical materials, nanomedicine, nanofabrication, materials preparation, ultraviolet spectra, visible spectra, scanning electron microscopy, Fourier transform infrared spectra, molecular biophysics, reduction (chemical), biochemistry, microorganisms, silver, nanoparticlesOther keywords: green synthesis, antimicrobial activity, silver nanoparticles, wild medicinal mushroom, Ganoderma applanatum Pat, Similipal Biosphere Reserve, Odisha, UV‐visible spectroscopy, particle analyser, scanning electron microscopy, dynamic light scattering analysis, Fourier transform infrared study, biomolecules, functional groups, silver reduction, AgNP stabilisation, biomedical application, pathogenic microorganisms, Escherichia coli, Bacillus subtilis, Staphylococcus epidermidis, Vibrio cholerae, Staphylococcus aureus, Shigella flexneri, Ag
Abbreviations
- AgNPs
- ‐ Silver Nanoparticles
- SPR
- ‐Surface plasmon resonance
- AgNO3
- ‐Silver nitrate
- nm
- ‐ Nanometer
- mm
- ‐Milimetre
43.
Saurabh Kumar Garg Srikumar Venugopal James Broberg Rajkumar Buyya 《Journal of Parallel and Distributed Computing》2013
Meta-schedulers map jobs to computational resources that are part of a Grid, such as clusters, that in turn have their own local job schedulers. Existing Grid meta-schedulers either target system-centric metrics, such as utilisation and throughput, or prioritise jobs based on utility metrics provided by the users. The system-centric approach gives less importance to users’ individual utility, while the user-centric approach may have adverse effects such as poor system performance and unfair treatment of users. Therefore, this paper proposes a novel meta-scheduler, based on the well-known double auction mechanism that aims to satisfy users’ service requirements as well as ensuring balanced utilisation of resources across a Grid. We have designed valuation metrics that commodify both the complex resource requirements of users and the capabilities of available computational resources. Through simulation using real traces, we compare our scheduling mechanism with other common mechanisms widely used by both existing market-based and traditional meta-schedulers. The results show that our meta-scheduling mechanism not only satisfies up to 15% more user requirements than others, but also improves system utilisation through load balancing. 相似文献
44.
A. Paul S. Venugopal J.G.P. Binner B. Vaidhyanathan A.C.J. Heaton P.M. Brown 《Journal of the European Ceramic Society》2013,33(2):423-432
Current generation carbon–carbon (C–C) and carbon–silicon carbide (C–SiC) materials are limited to service temperatures below 1800 °C and materials are sought that can withstand higher temperatures and ablative conditions for aerospace applications. One potential materials solution is carbon fibre-based composites with matrices composed of one or more ultra-high temperature ceramics (UHTCs); the latter are intended to protect the carbon fibres at high temperatures whilst the former provides increased toughness and thermal shock resistance to the system as a whole. Carbon fibre–UHTC powder composites have been prepared via a slurry impregnation and pyrolysis route. Five different UHTC compositions have been used for impregnation, viz. ZrB2, ZrB2–20 vol% SiC, ZrB2–20 vol% SiC–10 vol% LaB6, HfB2 and HfC. Their high-temperature oxidation resistance has been studied using a purpose built oxyacetylene torch test facility at temperatures above 2500 °C and the results are compared with that of a C–C benchmark composite. 相似文献
45.
Y. Kalyana Lakshmi N. Pavan Kumar P. Venugopal Reddy 《Journal of Superconductivity and Novel Magnetism》2013,26(9):2975-2980
The effects of silver doping on the magnetotransport and thermopower of La1?x Ag x MnO3 (0.05≤x≤0.30) have been investigated. For the sample with x=0.05, temperature dependent resistivity exhibits an insulating behavior, while thermopower is found to be large and negative over the measured temperature range. An increase in the Ag doping enhances the conductivity and shifts the metal-insulator transition temperature toward high temperature side. The low temperature thermopower data has been explained in terms of diffusion, magnon drag, and phonon drag effects and found that the magnon drag effect dominates in this region. Finally, the electrical transport in the high temperature region has been analyzed by using adiabatic small polaron hopping mechanism. 相似文献
46.
Fracture toughness tests were conducted on a Ti-62222 (titanium alloy) sheet being considered for use in high temperature aircraft applications in the as received condition and after exposing the pre-cracked specimens to a sustained stress intensity, K, level between 55 and 60.5 MPa
for 200 h at 350°C. It was concluded that the fracture toughness does not degrade as a result of exposure to high temperature and the K levels in this material. The tensile strength in the exposed condition also remained the same as in the as received condition. 相似文献
47.
Sachin Patil Sameer Sharma Anagha Nimbalkar Atmaram Pawar 《Drug development and industrial pharmacy》2013,39(3):315-326
ABSTRACTThe aim of the present study was to obtain cross-linked calcium-gellan beads containing diclofenac sodium as model drug, using full 33 factorial design. Drug quantity, pH of cross-linking solution, and speed of agitation were selected as variables for factorial design. The resultant beads were evaluated by scanning electron microscopy (SEM), percent yield, entrapment efficiency, micromeritic properties, swelling and drug release studies. The drug-loaded beads were spherical with size range of 0.85–1.8 mm. Percent yield and entrapment efficiency of various batches were in the range of 86.48–98.28% w/w and 72.52–92.74% w/w, respectively. Calcium-gellan beads containing diclofenac sodium showed pH-dependent swelling and drug release properties. Swelling and drug release were significantly higher in pH 7.4 phosphate buffer than 0.1N HCl. The swelling ratio for beads was up to 22 and 3 for phosphate buffer and 0.1N HCl, respectively. Cumulative diclofenac sodium release from calcium-gellan beads was 12–35% in 0.1N HCl within 2 h, whereas complete drug release was observed within 3–4 h in pH 7.4 phosphate buffer. 相似文献
48.
Krishnamoorthy Karthikesan Leelavinothan Pari Venugopal P. Menon 《Journal of Functional Foods》2010,2(2):134-142
The present study was undertaken to investigate the protective effect of tetrahydrocurcumin (THC) and chlorogenic acid (CGA) against streptozotocin (STZ)–nicotinamide (NA)-induced type 2 diabetes in adult Wistar rats. Diabetes was induced in experimental rats weighing 180–220 g, by a single intraperitoneal (i.p.) injection of STZ (45 mg/kg BW), 15 min after the (i.p.) administration of NA (110 mg/kg BW). THC (80 mg/kg BW) and CGA (5 mg/kg BW) were orally administered to diabetic rats for a period of 45 days. Fasting plasma glucose, glycosylated haemoglobin (HbA1C), thiobarbituric acid reactive substances (TBARS) and lipid hydroperoxides (LOOH) were significantly increased, whereas insulin, total haemoglobin (Hb), non-enzymic antioxidants (reduced glutathione (GSH), vitamin C, vitamin E and ceruloplasmin) were decreased significantly in diabetic rats. Though the diabetic rats treated with THC and CGA individual exerts beneficial effects in all the biochemical parameters in (STZ)-induced diabetic rats. The combined treatment with THC and CGA normalized all the above-mentioned biochemical parameters in STZ-induced diabetic rats. Normal pancreatic histological architecture in THC and CGA treated diabetic rats revealed that these phytochemical exert higher degree of protection when administered in combination than single treatment of individual compounds. 相似文献
49.
Precise measurements of shear wave velocities have been made in 20% cold worked and annealed samples of alloy D9 (Ti-modified austenitic stainless steel) to characterize the microstructural changes during annealing. The variation in wave velocity with annealing time exhibited a three stage behaviour. In the first stage, a slight increase in the velocity during recovery regime has been observed. This is followed by a significant increase in the velocity in the recrystallization regime (second stage) and reaching saturation on completion of recrystallization (third stage). Microstructural observations using optical metallography confirmed these three stages. The maximum variation in velocity is observed only when the polarization or the propagation direction of the shear wave is alingned with the cold working direction. Variation in shear wave velocity during annealing process, in general, is just opposite to that of the variation in longitudinal wave velocity. A number of velocity measurements were made by changing the propagation and polarization directions of the shear waves with respect to the cold working direction. Based on these measurements, a suitable velocity ratio parameter is suggested for determining the degree of recrystallization during annealing of cold worked alloy D9. 相似文献
50.
Yuling Yang Sameer R. Paital Narendra B. Dahotre 《Journal of materials science. Materials in medicine》2010,21(9):2511-2521
Silicon (Si) substitution in the crystal structure of calcium phosphate (CaP) ceramics has proved to generate materials with
improved bioactivity than their stoichiometric counterpart. In light of this, in the current work, 100 wt% hydroxyapatite
(HA) precursor and 25 wt% SiO2-HA precursors were used to prepare bioactive coatings on Ti-6Al-4V substrates by a laser cladding technique. The effects
of SiO2 on phase constituents, crystallite size, surface roughness, and surface energy of the CaP coatings were studied. Furthermore,
on the basis of these results, the effects and roles of SiO2 substitution in HA were systematically discussed. X-ray diffraction analysis of the coated samples indicated the presence
of various phases such as CaTiO3, Ca2SiO4, Ca3(PO4)2, TiO2 (Anatase), and TiO2 (Rutile). The addition of SiO2 in the HA precursor resulted in the refinement of grain size. Confocal laser microscopy characterization of the surface morphology
demonstrated an improved surface roughness for samples with 25 wt% SiO2-HA precursor compared to the samples with 100 wt% HA precursor processed at 125 cm/min laser speed. The addition of SiO2 in the HA precursor resulted in the highest surface energy, increased hydrophilicity, and improved biomineralization as compared
to the control (untreated Ti-6Al-4V) and the sample with 100 wt% HA as precursor. The microstructural evolution observed using
a scanning electron microscopy indicated that the addition of SiO2 in the HA precursor resulted in the presence of reduced cracking across the cross-section of the bioceramic coating. 相似文献