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901.
In this letter, isolated Si nanocrystal has been formed by dewetting process with a thin silicon dioxide layer on top. Scanning
capacitance microscopy and spectroscopy were used to study the memory properties and charge effect in the Si nanocrystal in
ambient temperature. The retention time of trapped charges injected by different direct current (DC) bias were evaluated and
compared. By ramp process, strong hysteresis window was observed. The DC spectra curve shift direction and distance was observed
differently for quantitative measurements. Holes or electrons can be separately injected into these Si-ncs and the capacitance
changes caused by these trapped charges can be easily detected by scanning capacitance microscopy/spectroscopy at the nanometer
scale. This study is very useful for nanocrystal charge trap memory application. 相似文献
902.
A procedure for the selective extinction of the scattered light based on "null ellipsometry" [R. M. A. Azzam and N. M. Bashara, Ellipsometry and Polarized Light (North-Holland, 1977)] is presented. The technique allows scattering measurement from individual layers of a multilayer component by extinguishing the scattered light from the other layer interfaces. The technique is easily applicable to multilayer components with nearly identical surface profiles at every interface and little significant bulk scattering. Analysis is provided to determine the conditions required to extinguish the light from the excluded interfaces isolating the scattered light from the desired interface. An analysis of sensitivity of the extinction conditions to experimental parameters and to layer optical thickness is also provided. Experimental data collected using the technique are compared with measurements made using a white-light optical surface profilometry. 相似文献
903.
Vibration and noise aspects play a relevant role in the lifetime and comfort of urban areas and their resi-dents.Among the different sources,the one coming from... 相似文献
904.
905.
ABSTRACT: A comparative photoluminescence analysis of as-prepared and chemically modified (by alkyl chains -C18H37) silicon and carbon nanoparticles dispersed in low-polar liquids is reported. Influence of the low-polar liquid nature and ambient temperature on photoluminescence of the nanoparticles has been investigated from the point of view of their possible application as thermal nanoprobes. 相似文献
906.
Laurent F Bignon A Goldnadel J Chevalier J Fantozzi G Viguier E Roger T Boivin G Hartmann D 《Journal of materials science. Materials in medicine》2008,19(2):947-951
Infections and their consequences are a considerable problem in orthopaedic surgery. Despite intravenous prophylactic antibiotic
administration, infection rates can reach in some occasions more than 1%. Indeed, the concentration in bone tissues is very
low with the majority of antibiotics. Because high local dose can be obtained, the local release of gentamicin from acrylic
bone cements has been shown to be efficient in preventing infections. However, for surgical procedures other than cemented
prostheses no other local antibiotic releasing device is clinically available. The purpose of this study was to validate the
concept of a gentamicin loaded bone substitute. About 125 mg of gentamicin were introduced into a HAP/TCP bone substitute
for prophylactic purpose, to enhance the efficiency of systemic antibiotic treatments. The release rate of gentamicin from
the bone substitute was investigated in vitro, in 0.9% sodium chloride solution. The rate appeared to be related to the bone
substitute volume. All the gentamicin was released in less than 48 h. This release rate corresponds to the recommendations
for the prophylactic use of antibiotics: the duration of the treatment should be less than 48 h, not to select antibiotic-resistant
bacterial strains. 相似文献
907.
The temperature profiles were calculated along and across seven packed columns (lengths 30, 50, 100, and 150 mm, i.d., 1 and 2.1 mm, all packed with Acquity UPLC, BEH-C 18 particles, average d(p) approximately 1.7 microm) and their stainless steel tubes (o.d. 4.53 and 6.35 mm). These columns were kept horizontal and sheltered from forced air convection (i.e., under still air conditions), at room temperature. They were all percolated with pure acetonitrile, either under the maximum pressure drop (1034 bar) or at the maximum flow rate (2 mL/min) permitted by the chromatograph. The heat balance equation of chromatographic columns was discretized and solved numerically with minimum approximation. Both the compressibility and the thermal expansion of the eluent were taken into account. The boundary conditions were determined from the experimental measurements of the column inlet pressure and of the temperature profile along the column wall, which were made with a precision better than +/-0.1 K. These calculation results provide the 3-D temperature profiles along and across the columns. The axial and radial temperature gradients are discussed in relationship with the experimental conditions used. The temperature map obtained permits a prediction of the chromatographic data obtained under a very high pressure gradient. 相似文献
908.
Pásek M Simurda J Christé G 《Philosophical transactions. Series A, Mathematical, physical, and engineering sciences》2006,364(1842):1187-1206
The morphology of the cardiac transverse-axial tubular system (TATS) has been known for decades, but its function has received little attention. To explore the possible role of this system in the physiological modulation of electrical and contractile activity, we have developed a mathematical model of rat ventricular cardiomyocytes in which the TATS is described as a single compartment. The geometrical characteristics of the TATS, the biophysical characteristics of ion transporters and their distribution between surface and tubular membranes were based on available experimental data. Biophysically realistic values of mean access resistance to the tubular lumen and time constants for ion exchange with the bulk extracellular solution were included. The fraction of membrane in the TATS was set to 56%. The action potentials initiated in current-clamp mode are accompanied by transient K+ accumulation and transient Ca2+ depletion in the TATS lumen. The amplitude of these changes relative to external ion concentrations was studied at steady-state stimulation frequencies of 1-5 Hz. Ca2+ depletion increased from 7 to 13.1% with stimulation frequency, while K+ accumulation decreased from 4.1 to 2.7%. These ionic changes (particularly Ca2+ depletion) implicated significant decrease of intracellular Ca2+ load at frequencies natural for rat heart. 相似文献
909.
This work investigates the efficiency of a chaotic micromixer using thermal lens spectrometry. The outlet of the mixing device was connected to a thermal lens detection head integrating the probe beam optical fibers and the sample capillary. The chaotic micromixer consisted of a Y-shaped poly(dimethylsiloxane) (PDMS) microchip in which ribbed herringbone microstructures were etched on the floor of the main channel. Due to the solvent composition dependence of the thermal lens response, the photothermal method was shown to be highly sensitive to nonhomogeneous mixing compared to fluorescence detection. The apparatus was applied to the determination of Fe2+ with 1,10-phenanthroline using flow injection analysis; a limit of detection of 11 microg L(-1) of iron was obtained. 相似文献