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141.
142.
Abnormal protein aggregation in the brain is linked to the pathogenesis of neurodegenerative diseases, including Alzheimer's disease (AD) and Parkinson's disease (PD). Recent studies revealed that the oligomeric form of aggregates is most likely the toxic species, and thus could be a good therapeutic target. To screen for potent inhibitors that can inhibit both oligomerisation and fibrillation of α-synuclein (α-syn), we systematically compared the antioligomeric and antifibrillar activities of eight compounds that were extracted from Chinese herbal medicines through three platforms that can monitor the formation of α-syn fibrils and oligomers in cell-free or cellular systems. Our results revealed that baicalein, a flavonoid extracted from the Chinese herbal medicine Scutellaria baicalensis Georgi ("huang qin" in Chinese), is a potent inhibitor of α-syn oligomerisation both in cell-free and cellular systems, and is also an effective inhibitor of α-syn fibrillation in cell-free systems. We further tested the protective effect of baicalein against α-syn-oligomer-induced toxicity in neuronal cells. Our data showed that baicalein inhibited the formation of α-syn oligomers in SH-SY5Y and Hela cells, and protected SH-SY5Y cells from α-syn-oligomer-induced toxicity. We also explored the effect of baicalein on amyloid-β peptide (Aβ) aggregation and toxicity. We found that baicalein can also inhibit Aβ fibrillation and oligomerisation, disaggregate pre-formed Aβ amyloid fibrils and prevent Aβ fibril-induced toxicity in PC12 cells. Our study indicates that baicalein is a good inhibitor of amyloid protein aggregation and toxicity. Given the role of these processes in neurodegenerative diseases such as AD and PD, our results suggest that baicalein has potential as a therapeutic agent for the treatment of these devastating disorders.  相似文献   
143.
The energy levels, oscillator strengths, line strengths, and transition probabilities for transitions among the terms belonging to the 3s23p2, 3s3p3, 3s23p3d, 3s23p4s, 3s23p4p and 3s23p4d configurations of silicon-like ions (Zn XVII, Ga XVIII, Ge XIX, and As XX) have been calculated using the configuration-interaction code CIV3. The calculations have been carried out in the intermediate coupling scheme using the Breit–Pauli Hamiltonian. The present calculations have been compared with the available experimental data and other theoretical calculations. Most of our calculations of energy levels and oscillator strengths (in length form) show good agreement with both experimental and theoretical data. Lifetimes of the excited levels have also been calculated.  相似文献   
144.
The Geosynthetic Reinforced Soil (GRS) Integrated Bridge System (IBS) is an alternative design method to the conventional bridge support technology. Closely spaced layers of geosynthetic reinforcement and compacted granular fill material can provide direct bearing support for structural bridge members if designed and constructed properly. This new technology has a number of advantages including reduced construction time and cost, generally fewer construction difficulties, and easier maintenance over the life cycle of the structure. These advantages have led to a significant increase in the rate of construction of GRS-IBS structures in recent years. This paper presents details on the instrumentation plan, short-term behavior monitoring, and experiences gained from the implementation of the first GRS-IBS project in Louisiana. The monitoring program consisted of measuring bridge deformations, settlements, strains along the reinforcement, vertical and horizontal stresses within the abutment, and pore water pressures. In this paper, the performance of instrumentation sensors was evaluated to improve future instrumentation programs. Measurements from the instrumentations also provide valuable information to evaluate the design procedure and the performance of GRS-IBS bridges. The instrumentation readings showed that the magnitude and distribution of strains along the reinforcements vary with depth. The locus of maximum strains in the abutment varied by the surcharge load and time that did not corresponds to the (45+?/2) line, especially after the placement of steel girders. A comparison was made between the measured and theoretical value of thrust forces on the facing wall. The results indicated that the predicted loads by the bin pressure theory were close to the measured loads in the lower level of abutment. However, the bin pressure theory under predicted the thrust loads in the upper layers with reduced reinforcement spacing. In general, the overall performance of the GRS-IBS was within acceptable tolerance in terms of measured strains, stresses, settlements and deformations.  相似文献   
145.
We evaluate and compare several closed form expressions of channel thermal noise used in circuits with MOSFET devices operating at high frequencies. To verify and compare these models, NMOS devices with channel widths of 120 μm (20 μm * 6 fingers) and channel lengths of 0.18, 0.36, and 0.54 μm were tested. A comparison of extracted and calculated noise data indicates that a model based on drain and overdrive voltages of short channel devices operating at RF frequencies provides the best match between extracted and calculated results for the channel thermal noise over a frequency range of 3 to 6 GHz and a gate overdrive voltage range of 0.2 to 1.2 V.  相似文献   
146.
This article is devoted to estimating the influence of magnetic field, electric field and initial stress in an elastic solid half-space under thermoelastic diffusion. The governing equations in the xz-plane are solved taking into consideration the Green–Lindsay (GL) model. The Reflection of dilatational (P) wave and Shear Vertical (SV) wave split into four waves: namely, P wave, thermal wave, mass diffusion wave and SV wave. The reflection phenomena of P and SV waves from the free surface of an elastic solid with thermoelastic diffusion under influence of magnetic field, electric field and initial stress is considered. The expressions for the reflection coefficients for the four reflected waves are obtained. These reflection coefficients are found to depend upon the angle of incidence θ of P and SV waves, thermoelastic diffusion, magnetic field, electric field and initial stress and other material parameters. The numerical values for the reflection coefficients are calculated analytically and presented graphically for varying values of these parameters.  相似文献   
147.
This article investigates the bending response of an orthotropic rectangular plate resting on two-parameter elastic foundations. Analytical solutions for deflection and stresses are developed by means of the simple and mixed first-order shear deformation plate theories. The present mixed plate theory accounts for variable transverse shear stress distributions through the thickness and does not require a shear correction factor. The governing equations that include the interaction between the plate and the foundations are obtained. Numerical results are presented to demonstrate the behavior of the system. The results are compared with those obtained in the literature using three-dimensional elasticity theory or higher-order shear deformation plate theory to check the accuracy of the simple and mixed first-order shear deformation theories.  相似文献   
148.
Nanoparticles hydroxyapatite (HAp) was prepared via an in situ biomimetic process with polyacrylic acid (PAAc) as a host polymeric material. Fourier transform infrared spectroscopy, transmission electron microscopy, scanning electron microscopy, X‐ray diffraction, thermogravimetric analysis, and differential scanning calorimetry were used to test the physical and chemical characteristics of biocomposites. The formation of HAp is confirmed by energy dispersion X‐ray analysis. Chemical binding between inorganic HAp and PAAc was investigated and discussed. HAp formation was initiated through the interaction of Ca2+ ions with the negative side groups of the polymer surface. The results showed that the biocomposites were formed with good homogeneity and thermal stability. Nanoparticles of HAp were uniformly distributed in the polymeric matrices. The resulting new materials are hoped to be applicable in the biomedical fields. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011  相似文献   
149.
Physical behavior of membrane blends of poly(vinyl alcohol) (PVA) doped with different weight percentage (wt %) of algal glycerol is reported. Solid‐state PVA/glycerol membranes were prepared by the solution casting method. Electrical impedance measurements were conducted to test the effect of varying the percentage of glycerol on the conductivity of the membranes. The measurements were made in the frequency and temperature ranges 1 Hz–1 MHz and 303–423 K, respectively. It was observed that the ionic conductivity increased with the increase of glycerol concentration as well as temperature. The thermal properties of the films were characterized. It was found that the thermal properties, particularly the melting point (Tm), for PVA blends exhibit a reduced value proportional to the algal glycerol content. Fourier transform infrared spectroscopy was utilized to evaluate the interactions between the glycerol and PVA. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 4482–4489, 2013  相似文献   
150.
Wool/viscose (60/40) and cotton/wool (70/30) blended fabrics have been easy-care finished in the presence of certain nitrogenous additives to produce readily dyeable cationic cellulose for competitive dyeing with wool dyes. The enhancement of easy care properties and improvement in post-dyeing of the finished fabrics were determined by the nature of substrate (wool/viscose > cotton/wool), type of catalyst (ammonium persulfate > ammonium sulfate > ammonium chloride > none), the kind of nitrogenous additive, as well as the type of polyethylene glycol (PEG-400 > PEG-200 > NONE). Using triethanolamine hydrochloride as a reactive/nitrogenous additive (30 g/L) in the finishing formulation as well as curing at 150°C/3 min make it possible to attain higher fabric resiliency along with better dye receptivity, regardless of the used anionic dye. However, the change in dyeing and fastness properties of obtained dyeing is governed by the nature of the anionic dye.  相似文献   
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