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151.
152.
Climate variations affect timber structures by causing moisture induced stresses which may lead to cracks in timber members. The paper presents experimentally determined moisture induced stresses that arise perpendicular to the grain of glulam specimens during exposure to 1-dimensional drying and wetting. Although to a certain extent reduced by creep effects, the determined tensile stresses can significantly exceed the characteristic tensile strength of glulam. Additional measurements of moduli of elasticity (E) and hygroexpansion coefficients (α) revealed that these parameters are strongly affected by the geometrical configuration (pith locations) of the specimens. By means of all the parameters determined here, it can be avoided that parameters have to be selected from different literature sources, which introduces large uncertainties into the numerical simulations. 相似文献
153.
Autonomous control of vehicles has recently attracted considerable attention. In this sense, vehicle merging has become an important topic in this field of research. However, in conventional studies, the controlled vehicle must calculate the movement of other surrounding vehicles to complete the merge, requiring high computational costs. In this paper, we focus on dragonfly behavior to solve this issue. Indeed, insects can behave adaptively in the complex real world in spite of the limited size of their brains. They reduce the computational requirements of their brain by relying on different properties of their surroundings, basing their intelligent behaviors on simple strategies. The behavior of a dragonfly when chasing a prey is an example of these strategies. In this study, we address the vehicle merging maneuver by applying dragonfly’s strategies to control the movement of the merging vehicle. We propose a simple control method inspired by the aforementioned strategies and, finally, we present simulation results that were conducted to demonstrate the effectiveness of this method. 相似文献
154.
Estimate of Suspended Sediment Concentration from Monitored Data of Turbidity and Water Level Using Artificial Neural Networks 总被引:2,自引:0,他引:2
Vanessa Sari Nilza Maria dos Reis Castro Olavo Correa Pedrollo 《Water Resources Management》2017,31(15):4909-4923
Artificial neural networks (ANNs) are promising alternatives for the estimation of suspended sediment concentration (SSC), but they are dependent on the availability data. This study investigates the use of an ANN model for forecasting SSC using turbidity and water level. It is used an original method, idealized to investigate the minimum complexity of the ANN that does not present, in relation to more complex networks, loss of efficiency when applied to other samples, and to perform its training avoiding the overfitting even when data availability is insufficient to use the cross-validation technique. The use of a validation procedure by resampling, the control of overfitting through a previously researched condition of training completion, as well as training repetitions to provide robustness are important aspects of the method. Turbidity and water level data, related to 59 SSC values, collected between June 2013 and October 2015, were used. The development of the proposed ANN was preceded by the training of an ANN, without the use of the new resources, which clearly showed the overfitting occurrence when resources were not used to avoid it, with Nash-Sutcliffe efficiency (NS) equals to 0.995 in the training and NS = 0.788 in the verification. The proposed method generated efficient models (NS = 0.953 for verification), with well distributed errors and with great capacity of generalization for future applications. The final obtained model enabled the SSC calculation, from water level and turbidity data, even when few samples were available for the training and verification procedures. 相似文献
155.
Toshio Shimoo Masahiro Ito Kiyohito Okamura Michio Takeda 《Journal of the American Ceramic Society》2001,84(1):111-116
Electron-beam-cured polycarbosilane fibers were heat-treated at 673–1773 K in a tube evacuated to 1.3 × 10−1 Pa and then exposed at 1873 K in argon. The effect of vacuum heat treatment on improving the high-temperature stability of low-oxygen SiC fibers was investigated by examining gas evolution, grain growth, surface composition, tensile strength, and morphology. The fibers heat-treated at <1173 K lost strength, because of the vigorous generation of residual hydrogen. A minute amount of oxygen in the atmosphere caused the active oxidation of SiC during heat treatment at >1673 K, resulting in severe strength degradation for the as-heat-treated fibers. Vacuum heat treatment at 1573 K provided the best characteristics in low-oxygen SiC fibers. 相似文献
156.
Betina Piqueras-Fiszman Vanessa Harrar Jorge Alcaide Charles Spence 《Food quality and preference》2011,22(8):753-756
In many categories, weight has been found to influence how users perceive and appraise products. However, to date, the influence of the weight of the dish in which food is served on people’s perception has not been studied empirically. This exploratory study was therefore designed to investigate whether the weight of the container would exert a significant influence on people’s sensory and hedonic responses to the food consumed from it. Three bowls, identical except for the fact that they were different weights, were filled with exactly the same yoghurt. Consumers evaluated the yoghurt samples from the three bowls holding them with one hand, one at a time. Participants rated flavor intensity, density, price expectation, and liking using 9-point likert scales. Significant effects were found for all attributes except for flavor intensity. The effects on both density and price expectation ratings were highly significant.These findings are potentially relevant for designers and those working in restaurants, the hospitality sector, and food production, since the design and choice of dishes (or packages) of various weights could potentially be used to help enhance and/or modify the way in which consumers perceive and experience the food consumed from them. 相似文献
157.
Oxidative Stability and Changes in Chemical Composition of Extra Virgin Olive Oils After Short‐Term Deep‐Frying of French Fries
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Emília Akil Vanessa Naciuk Castelo‐Branco André Mesquita Magalhães Costa Ana Lúcia do Amaral Vendramini Verônica Calado Alexandre Guedes Torres 《Journal of the American Oil Chemists' Society》2015,92(3):409-421
We aimed at investigating oxidative stability and changes in fatty acid and tocopherol composition of extra virgin olive oil (EVOO) in comparison with refined seed oils during short‐term deep‐frying of French fries, and changes in the composition of the French fries deep‐fried in EVOO. EVOO samples from Spain, Brazil, and Portugal, and refined seed oils of soybean and sunflower were studied. Oil samples were used for deep‐frying of French fries at 180 °C, for up to 75 min of successive frying. Tocopherol and fatty acid composition were determined in fresh and spent vegetable oils. Tocopherol, fatty acid, and volatile composition (by SPME–GC–MS) were also determined in French fries deep‐fried in EVOO. Oil oxidation was monitored by peroxide, acid, and p‐anisidine values, and by Rancimat after deep‐frying. Differential scanning calorimetry (DSC) analysis was used as a proxy of the quality of the spent oils. EVOOs presented the lowest degree of oleic and linoleic acids losses, low formation of free fatty acids and carbonyl compounds, and were highly stable after deep‐frying. In addition, oleic acid, tocopherols, and flavor compounds were transferred from EVOO into the French fries. In conclusion, EVOOs were more stable than refined seed oils during short‐term deep‐frying of French fries and also contributed to enhance the nutritional value, and possibly improve the flavor, of the fries prepared in EVOO. 相似文献
158.
Incorporation of Alpha‐Linolenic Acid and Enhancement of n‐3 Fatty Acids in Nile Tilapia: a Factorial Design
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Vanessa Vivian Almeida Schneider Fabiana Carbonera Paula Fernandes Montanher Ana Paula Lopes Makoto Matsushita Jesuí Vergílio Visentainer 《Journal of the American Oil Chemists' Society》2015,92(5):693-700
A 22 factorial design (two factors at two levels, in triplicate) was performed to investigate the influence of factors A (time of treatment, 15 and 30 days) and B (chia oil content in a supplemented diet, at 2.1 and 4.2 %) in three responses of interest referring to: (a) the incorporation of alpha‐linolenic acid (LNA) in lipids of Nile tilapia fillet; (b) the enhancement of n‐3 fatty acids; and (c) the decrease in the omega‐6/omega3 (n‐6/n‐3) ratio in fish. Factors A and B were significant in the three regression models obtained and the interaction AB was a significant contributor to the LNA and n‐6/n‐3 ratio. Analysis of variance suggested three significant and predictive mathematical models. Response surfaces analyses from designs indicated higher LNA and n‐3 contents and a lower n‐6/n‐3 ratio using both factors A and B in the higher levels (30 days of treatment and 4.2 % of chia oil in the diet for fish) chosen for this study. 相似文献
159.
160.
Yuichiro Hirota Yohei Maeda Norikazu Nishiyama Takashi Furusawa Akira Ito 《American Institute of Chemical Engineers》2016,62(3):624-628
Ionic liquid/polyvinylidene fluoride composite membrane was successfully prepared by impregnation method and used for the separation on organic chemical hydride process. The separation factors of C6H6/H2 and C6H12/H2 in the ternary mixture system were 7500 and 300, respectively. The ionic liquid membrane showed an excellent possibility as a technology of H2 purification in the organic chemical hydride process by removing aromatic hydrocarbon and cycloalkane simultaneously from the ternary system. © 2015 American Institute of Chemical Engineers AIChE J, 62: 624–628, 2016 相似文献