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1.
Tensile testing of a modified 9Cr–1Mo steel in two microstructural conditions (710T– normalized at 1100°C, tempered at 710°C, and 550T – normalized at 1100°C tempered at 550°C) in the temperature range 25–450°C, under strain rates of 2.3×10-5–2.3×10-3s-1, exhibited serrated flow curves, with serrations appearing almost at the onset of deformation and disappearing before ultimate strengths were attained. The serrated flow curves (characteristics of dynamic strain ageing) were accompanied by increased ultimate strengths, loss of ductility and negative strain-rate sensitivity, relative to the ambient temperature properties. However, the increase in ultimate strength and the reduction in ductility were much larger for 710T specimens, as compared to 550T ones. In the dynamic strain ageing regime, the work-hardenability of 710T specimens increased rapidly while that of 550T specimens remained practically unaffected. Based on the microstructural consideration and the observed activation energy of 45 kJ mol-1, it is proposed that serrations are initiated by a nitrogen atmosphere formation on the waiting dislocations by a pipe diffusion mechanism, and they disappear by diffusion to the precipitate sinks during deformation. Because the fine alloy carbide precipitates in 550T specimens are more effective sinks than those of 710T ones, they can cause much faster depletion of the atmosphere, resulting in a much smaller effect of dynamic strain ageing on the tensile properties of 550T specimens. 相似文献
2.
SHELF-LIFE MODELING OF SWEETENED CONDENSED MILK BASED ON KINETICS OF MAILLARD BROWNING 总被引:1,自引:0,他引:1
A. A. PATEL H. GANDHI SUDHIR SINGH G. R. PATIL 《Journal of Food Processing and Preservation》1996,20(6):431-451
Nonenzymatic browning and related changes were monitored in commercial sweetened condensed milk stored at 7, 15, 30, 45 and 55C. Darkening of the color measured in terms of absorbance (100 - reflectance percent) followed zero-order kinetics, the apparent activation energy (Ea ) being 45.2 kJ/mol at 7–30C and 139.9 kJ/mol at > 30–55C. Hydroxy-methyl-furfural (HMF) showed a first-order increase, the associated Ea values being smaller than those for absorbance. The pH exhibited a linear decline after a small initial rise at 30C and below. As browning progressed, the coffee whitening ability of the product decreased along zero-order kinetics. The Q10 values for these variables ranged from 1.21 to 1.84 for temperatures up to 30C and were nearly 2–3 times higher above 30C. The sensory color score was negatively correlated with absorbance. The linear regression of color score on absorbance and the temperature dependence of the latter as expressed by Arrhenius relationship were combined into a mathematical model which could be useful in predicting the product's shelf-life. 相似文献
3.
SIMULATION OF THAWING OF FOODS USING FINITE ELEMENT METHOD 总被引:2,自引:0,他引:2
4.
YOUSSEF S. HAFEZ ALI I. MOHAMED GURBAX SINGH FAWZY M. HEWEDY 《Journal of food science》1985,50(5):1271-1274
Two hundred grams of soybean seeds (moisture contents of 7.4, 15.3, 22.5, and 30.5%) were irradiated at dose levels of 0, 1, 5, 10, 20, 40, 60, 80 and 100 KGy using Cobalt-60 source. Radiation dose of 100 KGy caused a decrease in the percentage of nitrogen solubility from 80.3 to 67.2, 80.3 to 57.8, and 68.1 to 48.8 when deionized H2O, 0.6M NaCl, and 0.2M Cacl2 were used as solvents, respectively. Inhibition of 71% of lipoxygenase activities, 25.4% trypsin inhibitor activities, and 16.7% chymotrypsin inhibitor activities were found when the soybean seeds were irradiated at 100 KGy. 相似文献
5.
Experimental residence-time distribution (RTD) characteristics of an extrusion process may be used to estimate the extent of mixing experienced in the extruder. Using earlier theories of laminar mixing and striation thickness reduction, a new approach to estimate efficacy of mixing of two phases in the mixing zone of the extruder is proposed. Predicting the time required to achieve complete mixing and comparing it with the minimum time (plug flow time) that the extrudate spends in the mixing zone gives a ratio that can be used to evaluate the adequacy of extruder operating conditions for good mixing of gas/fluid injection and extrudate. Twin-screw extrusion of cornmeal with carbon dioxide injection were used to investigate the effect of CO2 injection pressure and extruder screw speeds on mixing. Lower CO2 injection pressures (25 bars) and lower screw speeds (150 rpm) were theoretically shown to enhance mixing. Scanning electron micrographs (SEMs) of experimental samples taken showed smaller and more uniform cell structures for those conditions which were predicted to favor better mixing. 相似文献
6.
In this paper, device performance of graphene nanoribbon field effect transistor (GNRFET) with different doping concentrations in different parts of the channel is reported. The study is performed by using atomistic simulations based on self-consistent solution of Schrodinger’s and Poisson’s equation within the non-equilibrium Green’s function formalism. The transfer and output characteristics suggest that device performance with n-type doping in the channel is better with smaller supply voltage compared to higher supply voltage. On increasing the n-type doping concentration, we obtained better on-current and output characteristics in comparison with undoped and p-type doped channel GNRFET. Further, we introduced step-doping profile in the graphene nanoribbon (GNR) channel and found that the device gives better on-current and good saturation condition when compared to undoped or uniformly-doped channel. 相似文献
7.
NAGAPPA S. KARABASANAVAR S.P. SINGH UMAPATHI V. DEEPAK KUMAR SUNIL N. SHEBANNAVAR 《Journal of food quality》2011,34(2):142-149
ABSTRACT
A highly species‐specific polymerase chain reaction (PCR) assay was developed for the authentic identification of goat. A product of 436 bp was amplified using newly designed primers against mitochondrial D‐loop region. The possibility of cross‐amplification was ruled out by considering as many as 25 other animal species. Suitability of the developed goat species‐specific PCR assay was confirmed for in raw, cooked (60, 80 and 100C for 30 min) and micro‐oven‐processed meat samples (n = 20 each). A sensitivity of 0.1% was established for detection of adulteration and limit of detection of goat DNA was 0.1 pg. This investigation presents a novel PCR assay with its newly designed primers that could be used for the authentic identification of goat species.PRACTICAL APPLICATIONS
This work details about a novel diagnostic polymerase chain reaction, which could be used for authentic identification of goat species. This approach could be used for the confirmation of goat tissues in raw, cooked, as well as adulterated samples. The developed technique has also applications in the forensic analysis of wild animal‐related disputes, where this work could solve the problem of goat‐related issues. 相似文献8.
Pushpinder SINGH 《Frontiers of Computer Science in China》2014,(5):741-752
In this paper, we propose some distance measures between type-2 fuzzy sets, and also a new family of utmost distance measures are presented. Several properties of differ- ent proposed distance measures have been introduced. Also, we have introduced a new ranking method for the ordering of type-2 fuzzy sets based on the proposed distance measure. The proposed ranking method satisfies the reasonable prop- erties for the ordering of fuzzy quantities. Some properties such as robustness, order relation have been presented. Lim- itations of existing ranking methods have been studied. Fur- ther for practical use, a new method for selecting the best alternative, for group decision making problems is proposed. This method is illustrated with a numerical example. 相似文献
9.
Extended milling of rice decreased the incidence of mycoflora and reduced black tip discoloration but reduced the head rice yield and kernel weight. Protein content, ash, reducing sugars, nonreducing sugars and free fatty acids increased whereas amylose decreased significantly with the increase in the number of discolored grains. Discolored rice required significantly less time to cook, showed decreased water uptake, reduced kernel elongation and losses. Cooking time decreased; water uptake, elongation in cooked rice and gruel solid loss increased with an increase in the degree of milling. Correlation coefficients between the different variables were calculated. 相似文献
10.
C.R. STITES F.K. McKEITH S.D. SINGH P.J. BECHTEL D.J. JONES D.H. MOWREY 《Journal of Muscle Foods》1994,5(4):367-376
This study was designed to evaluate the visual and palatability characteristics of boneless cured hams and fresh loin chops from pigs fed diets containing 0, 5, 10 or 20 ppm of the phenethanolamine, ractopamine hydrochloride (RAC). Sixty pigs were blocked by starting weight and randomly assigned to pens (four pigs/pen) within each of three blocks. Treatments were then randomly assigned to pens (six pens of the 0–ppm level and three pens each for the 5, 10 and 20 ppm RAC levels). Animals were slaughtered by weight block after approximately 48 days on trial. Fresh pork hams and loin sections (10–14th rib) were removed from the right side of the carcasses for subsequent analysis. Boneless hams were manufactured using commercial curing procedures. RAC had no effect (P > 0.05) on visual or palatability attributes of ham slices or boneless loin chops. Moisture content of the longissimus muscle from RAC treatments was lower (P < 0.05) than controls; however, this difference was small. These results indicate that RAC had no affect on the visual or palatability characteristics of boneless cured and smoked hams or fresh boneless pork loin chops. 相似文献