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991.
表面活性剂对碳钢的缓蚀作用及与缓蚀剂的协同效应 总被引:3,自引:4,他引:3
采用动电势扫描法测定了碳钢在饱和(NH4)2CO3溶液中的阳极极化曲线,研究了几种表面活性剂与缓蚀剂复配后的协同缓蚀作用。结果表明:几种表面活性剂均具有较好的缓蚀性能,体系中添加0.1%的量,缓蚀效率都接近90%:当0.05%壬基酚聚氧乙烯醚(TX-10)与0.05%四丁基碘化铵复配时,协同缓蚀效率可达93.3%;应用动电势扫描法能够快速、简便地测定腐蚀速率和评选缓蚀剂。 相似文献
992.
This paper presents an investigation of the influence of plasma spray process conditions on the in-flight particle behavior
and their cumulative deposition to form a coating on the substrate. Three-dimensional computational fluid dynamics (CFD) analyses
were performed to model the in-flight particle behavior in the plasma-spray process and their deposition on the substrate.
The plasma spray was modeled as a jet issuing from the torch nozzle through the electrical heating of the arc gas. In the
model, particles were injected into the plasma jet where they acquired heat and momentum from the plasma, some got melted
and droplets were formed. By means of a droplet splatting model, the particle in-flight data generated by the CFD analyses
were further processed to build up an imaginary three-dimensional deposition profile on a flat stationary substrate. It is
found that the powder carrier gas flow rate influences the particle distribution on the substrate by imparting an injection
momentum to the particles that were directed radially into the plasma jet in a direction perpendicular to the plasma jet.
The larger sized particles will acquire higher injection momentum compared with the smaller sized particles. This causes particle
distribution at the substrate surface that is elliptical in shape with the major axis of ellipse parallel to the particle
injection port axis as illustrated in Fig. 1. Larger particles tend to congregate at the lower part of the ellipse, due to
their greater momentum. The distribution of particle size, temperature, velocity, and count distribution at the substrate
was analyzed. Further, based on the size and the computed particle temperature, velocity histories, and the impact sites on
the substrate, the data were processed to build up a deposition profile with the Pasandideh-Fard model. The shapes of deposition
profiles were found to be strongly driven by the segregation effect. 相似文献
993.
Depositing silver on magnesium alloy by both electroless plating and organic coatings was studied. The organic coating was made by immersing samples in organosilicon heat-resisting varnish. In this method the organic coating acts as interlayer between the substrate and silver film. When the reaction starts, silver deposits directly on the interlayer. X-ray diffraction and SEM analysis were used to determine the composition and morphology of the interlayer and silver film. The potentiodynamic polarization curves for corrosion studies of coated magnesium alloys were performed in a corrosive environment of 3.5% NaCl(mass fraction) at neutral pH (6.9). The results indicate that compared with the substrate, the corrosion resistance of coated magnesium alloys increases greatly. Moreover, the method proposed in this work is environmentally friendly, non-toxic chemicals were used. In addition, it provides a new concept for the corrosion inhibition of magnesium alloys. 相似文献
994.
Morphology, structure and formation mechanism of silicide coating by pack cementation process 总被引:3,自引:0,他引:3
The MoSi2 coating on C 103 niobium based alloy was prepared by pack cementation method. The formative mechanism, morphology and structure of coating were investigated. The silicide coating was formed by reactive diffusion obeying parabolic rule during pack cementation process. It is found that the composite structural coating is composed of three inferior layers as follows. The main layer is composed of MoSi2, the two phases' transitional layer consists of NbSi2 and a few NbsSi3 and the diffuse layer is composed of NbsSi3. The dense amorphous glass layer formed on the surface at high temperature oxidation circumstance can effectively prevent the diffusion of oxygen into coating. 相似文献
995.
The relationship between the yield ratio and the material constants,b andN, of the Swift equation for hotrolled low carbon steels has been established. The yield ratio calculated by using the Swift
equation agrees well with an experimentally obtained yield ratio. It was found that the yield ratio decreases with an increasing
value ofN or with a decreasing value ofb. It was also found, however, that high yield strength is associated with small values of bothb andN. Therefore, to obtain both high yield strength and low yield ratio, a detailed microstructural control is needed to determine
the optimum values ofb andN. 相似文献
996.
A super-hydrophilic functional ceramic was prepared by adjusting the chemical components of ceramic glaze. Effect of surface flee energy of ceramic glaze on oil droplet shape and its behavior in water were studied. The results show that water can spread on ceramic surface with high surface free energy, and oil droplet can aggregate rapidly and separate from the ceramic surface in water. For the ceramic with lower surface free energy, the polar shares are dependant on its easy-cleaning property. The higher the polar shares, the better the easy-cleaning property, and the easier the droplet separates from the ceramic surface in water. 相似文献
997.
998.
NdFeB磁体的二次化学镀耐蚀性能 总被引:6,自引:0,他引:6
研究了NdFeB磁体表面超声波化学镀和二次化学镀Ni-
P合金的耐腐蚀性,用扫描电子显微镜和X射线衍射仪分析了镀层的组织结构,结果表明,该工艺制备的镀层明显地提高了NdFeB磁体的耐蚀性能. 相似文献
999.
LIANGChenghao MOUZhanqi 《稀有金属(英文版)》2002,21(4):266-270
The electrochemical behaviors of commercially pure titanium(CP Ti) and Co-Cr alloy in Ringer‘s solution have been investigated.The results indicate that the electric potential of passive region for CP Ti is up to 3000mV,and its passive current density is 3.078 μA/cm^2,The excellent corrosion resistance of CP Ti can be attributed to the formation of TiO2 oxide film.The passive region of Co-Cr alloy is 770mV,which is narrower than that of CP Ti.However,no hystersis loops are found in the reverse scanning curves of Cu-Cr alloy.A complex oxide film of Co3O4,Co2O3,and Cr2O3 formed on the surface provides Co-Cr alloy with a stable electrochemistry property.The corrosion rates of the crevice samples increase with the pH value of medium decreasing.The electron probe microanalyzer(EPMA) analysis indicates that Ti in CP Ti and Co,Cr in Co-Cr alloy dissolve in crevice area due to the Sealed-Cell effect. 相似文献
1000.