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排序方式: 共有413条查询结果,搜索用时 10 毫秒
31.
A. Khodabakhshi V. Abouei N. Mortazavi S. H. Razavi H. Hooshyar M. Esmaily 《Tribology - Materials, Surfaces & Interfaces》2015,9(3):118-127
The effects of cold work process between aging and solution heat treatment on the microstructure, hardness and the tribologic behaviour of a copper–beryllium (Cu–Be) alloy C17200 were investigated. The wear behaviour of the alloys was studied using ‘pin on disc’ method under dry conditions. The results show that the formation of fine grained structure and γ phase particles enhances the mechanical properties of the alloy; nonetheless, they do not reduce the wear rate. This is attributed to the capability of the softer specimens to maintain oxygen rich compounds during the dry sliding test. 相似文献
32.
E. Bahmani V. Abouei Y. Shajari S. H. Razavi O. Bayat 《Surface Engineering and Applied Electrochemistry》2018,54(4):350-358
Aluminum matrix nano-composites have been widely used in various fields such as aerospace, automobile, and packing industries. In this study, the effect of nano-SiC content on the microst-ructure, wear resistance and micro-hardness of Al–Si/SiC nano-composite was investigated. In this regard, Al–Si matrix was reinforced by different amounts of nano-SiC: 0, 0.5, 1, 1.5, 3, 5, 10 wt %. The results showed that with increasing the nano-SiC weight ratio, nano-particles are agglomerated and unsuitable sintering increases the porosity, as pores and cavities. For more than 1.5% weight ratio of nano-SiC in the matrix, the wear resistance and the micro-hardness decreased. The results of the wear test, scanning electron microscopy, energy dispersive X-ray spectroscopy and worn surfaces showed that the dominant wear mechanism is controlled by nano-SiC contents. This study indicated that with adding nano-SiC particles more than the optimal content, wear resistance and micro-hardness of Al–Si/SiC nano-composite increased more than twice. 相似文献
33.
Naser Hosseini Ali Fazili Mohammad Reza Derakhshandeh Leila Nikzad Milad Bahamirian Mansour Razavi 《Ceramics International》2021,47(11):15771-15782
In this study, the effect of Co addition on microstructural and mechanical properties of WC-B4C–SiC composites sintered by spark plasma sintering (SPS) method was investigated. For this purpose, three batches of WC-B4C–SiC with different contents of Co (10 vol%, 15 vol%, and 20 Vol %) were sintered at 1400 °C. The results of X-ray diffraction (XRD) analysis of the samples indicated the formation of W2B5, W3CoB3 as well as the remained C phases and unreacted SiC phase. It was observed that by increasing the Co content, the amount of W2B5 phase reduces and W3CoB3 and C contents increase. Therefore, W2B5 peaks were not detected in the sample containing 20vol% Co. Relative density values above 97% were obtained for all the composites. However, a decrease was observed in relative density by increasing the Co content in the composites. The highest flexural strength (510 ± 42 MPa), fracture toughness (10.34 ± 0.82 MPa m1/2), and hardness (20.63 ± 0.75 GPa) were also obtained for the sample containing 10vol% Co compared to the other samples. In addition, Transgranular fracture of SiC as well as pulling out of W3CoB3 and W2B5 particles were observed in the fracture surface micrographs of the samples. The presence of micro-cracks in the SiC grains, fracture of W3CoB3 grains, and crack deflection was reported as dominant toughening mechanisms. 相似文献
34.
Two types of synbiotic ice cream containing 1% of resistant starch with free and encapsulated Lactobacillus casei (Lc-01) and Bifidobacterium lactis (Bb-12) were manufactured. The survival of L. casei and B. lactis were monitored during the product’s storage for 180 days at −20 °C. The viable cell number of L. casei and B. lactis in the free state in prepared ice cream mixture was 5.1 × 109 and 4.1 × 109 CFU/mL at day one and after 180 days storage at −20 °C, these numbers were decreased to 4.2 × 106 and 1.1 × 107 CFU/mL, respectively. When we encapsulated the mentioned probiotic bacteria in calcium alginate beads, the probiotic survival raised at rate of 30% during the same period of storage at same temperature. In general, the results indicated that encapsulation can significantly increase the survival rate of probiotic bacteria in ice cream over an extended shelf-life. The addition of encapsulated probiotics had no significant effect on the sensory properties of non-fermented ice cream in which we used the resistant starch as prebiotic compound. 相似文献
35.
P. Ebrahimi S. M. Razavi S. Ismaeili M. Azarpour 《Petroleum Science and Technology》2013,31(11):1188-1195
Recognition of hydrocarbon migration is so vital for petroleum exploration. Developing intelligent systems (artificial neural network) enable experts to achieve more details from seismic data. Although detection of migration direction using seismic data is difficult, Chimney-cube analysis overcomes this problem. The authors used several filters, seismic attributes, neural network (supervised and unsupervised), and interpreters' viewpoints. In supervised method artificial and human intelligence cover their limitations and in unsupervised method the authors eliminate the experts' views. Chimney recognizes the migration direction and locates the spill points, mud volcanoes, gas seepages, sealing, and nonsealing faults and finally the origin of hydrocarbon. 相似文献
36.
The effect of pH,salts and sugars on the rheological properties of cress seed (Lepidium sativum) gum
Fataneh Behrouzian Seyed M. A. Razavi Hojjat Karazhiyan 《International Journal of Food Science & Technology》2013,48(12):2506-2513
Effect of shear rate (15–600 s?1), gum concentration (1–2%), pH (3–9), sucrose (10–40%), lactose (5–15%), NaCl (100–300 mm ) and CaCl2 (5–50 mm ) was evaluated on apparent viscosity (ηa), flow behaviour index (n), consistency coefficient (K) and yield stress (τ0) indices of cress seed gum (CSG) solutions. Different rheological models were used to fit the experimental data, although the Herschel–Bulkley model was found the best model. An increase in gum concentration led to an increase in τ0, ηa, and k and a decrease in n values. The addition of salts lowered the k value; however, the n value showed slight significant change. The presence of sugar resulted in the enhancement of n, k, τ0 and ηap values. The existence of yield stress and pseudoplastic behaviour of CSG, its stability against salts, wide range of pH and synergic effect of sugar make it a good thickener and stabiliser in food formulations. 相似文献
37.
Monitoring the aging of beers using a bioelectronic tongue 总被引:2,自引:0,他引:2
Mahdi Ghasemi-Varnamkhasti María Luz Rodríguez-MéndezSeyed Saeid Mohtasebi Constantin ApetreiJesus Lozano Hojat AhmadiSeyed Hadi Razavi Jose Antonio de Saja 《Food Control》2012,25(1):216-224
This paper deals with the implementation and the application of a bioelectronic tongue including three enzymatic biosensors based on tyrosinase and phthalocyanines as electron mediators, to evaluate the changes that occur during the aging of beers. For this purpose, alcoholic and non alcoholic beers, packaged in can and bottle, have been analyzed using cyclic voltammetry. The electrochemical signals showed significant changes during the aging process. The features extracted from the cyclic voltammograms have been used to perform Principal Component Analysis (PCA) and Linear Discriminant Analysis (LDA). Data have revealed a clear discrimination among the beer classes in the aging process and the results were confirmed by Probabilistic Neural Networks (PNN) with Radial Basis Functions (RBF) and FeedForward Networks with Backpropagation (BP) learning method. The bioelectronic tongue has demonstrated a good capability to discriminate and classify the beer types satisfactorily in such a way, for all beer treatments, full classification accuracy was found. 相似文献
38.
Maryam BahramParvar Seyed M.A. Razavi Mostafa Mazaheri Tehrani 《International Journal of Food Science & Technology》2012,47(12):2655-2661
Mixture design was used to determine the optimum ratio as well as concentration of basil seed gum (BSG), guar gum (GG) and carboxymethyl cellulose (CMC) in the formulation of ice cream stabilisers. Predicted equations and contour plots of physicochemical responses were also generated. Generally, increasing the ratio of BSG in gums mixture increased the apparent viscosity of ice cream mixes and decreased the melting rate. Increasing the proportion of GG at concentration of 0.35% enhanced overrun of samples. High ratios of BSG at concentration of 0.35% and CMC at concentration of 0.15% increased the fat destabilisation in ice creams. Combination of 84.31% BSG and 15.69% CMC at concentration of 0.35% proposed as optimum formulation which verified in practice. Introducing BSG as a novel source of stabiliser could be promising as alternative and improve the quality and diversity of ice cream and related products. 相似文献
39.
Attempts have been made to study the fracture behavior and environmental stress cracking resistance (ESCR) of HIPS/PE blends. The effect of compatibilization on their properties was also studied. EWF tests were conducted to measure the essential specific work of fracture (we) and non-essential specific work of fracture (βwp). The ESCR of the samples was investigated using a special modified tensile creep test under an aggressive environment (sunflower oil). It was found that EWF methodology could be applied to uncompatibilized and compatibilized HIPS/PE blends as well as HIPS. The essential specific work of fracture of compatibilized HIPS/PE blends was higher than uncompatibilized HIPS/PE blends and pure HIPS, while its non-essential work of fracture was higher than uncompatibilized blends and lower than pure HIPS. The results also showed that the ESCR of HIPS decreases with incorporation of PE, but an effective compatibilization of this blend increases its ESCR even higher than pure HIPS. The different properties of compatibilized and uncompatibilized blends and HIPS, in EWF and ESCR tests, were attributed to the different mechanisms of fracture in these materials. The different mechanisms of fracture were justified using morphological studies performed on fracture surfaces of each sample. SEM images showed that there is a reasonable correlation between mechanisms of fracture and microstructure of the samples. 相似文献
40.