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511.
Green beans (cv. Moncayo) were blanched at 65, 70, 75, 80, 85, 90 and 97 °C for 2.5, 5, 10, 20 and 40 min. Pectinesterase (PE) activity was highest in cell-wall-bound extracts of beans blanched at 70 °C/10 min. The lowest water-soluble pectin fraction, the highest EDTA-soluble pectin fraction and the lowest degree of esterification of the EDTA-soluble fraction were all recorded for the same temperature/time combination; these effects can therefore be attributed to PE activity. Chemical changes did not affect initial firmness of the beans, which was practically constant after blanching at 65, 70, 75 and 80 °C. Simple first-order models were adequate to establish softening kinetics for beans blanched at 85, 90 and 97 °C. In this temperature range, Kramer maximum force was the mechanical parameter that best characterised bean softening by blanching. For all temperatures, short-time blanching increased the coloration and total chlorophyll content of the samples with respect to fresh control, thus precluding the use of simple models. In the treated beans, the ascorbic acid content was consistently lower than in the control and decreased continuously with increasing time. Microphotographs showed no appreciable differences in morphology between fresh and blanched beans at 65, 70 and 75 °C, which would explain the similarity of mechanical behaviour in these samples. Blanching at 85, 90 and 97 °C caused loosening and swelling of the cell walls owing to breakdown of the pectic material, which again helps to explain the observed loss of firmness.  相似文献   
512.
513.
In order to improve Malvazija from Istria wine quality, we used two types of barrels: oak (of French and Croatian origin) and acacia (of Croatian origin). After 12 months ageing period all of the wines were analysed chemically and sensorially. Results showed marked differences between oak and acacia aged wines, especially in simple volatile phenol and oak lactones concentrations. During the ageing period a significant increase in furfural, 5-methylfurfural, guaiacol, eugenol and trans-eugenol was noticed. Results pointed out the importance of choosing the right barrels (oak or acacia) and time of leaving the wine in the barrels to achieve the desired goal. The highest rated wines were made in acacia barrels.  相似文献   
514.
月球车巡视探测的双目视觉里程算法与实验研究   总被引:2,自引:0,他引:2  
月球车在月面巡视的移动距离测量是实现安全有效探测的重要保障.基于视觉里程计的定位方法是解决月面滑移,提高行驶里程推算精度的有效方法,对月球车实现高精度定位具有重要意义.本文对双目视觉里程算法的设计及实现技术进行了深入研究,并对基于不同特征提取算法的视觉里程定位方法进行了实验验证,通过与高精度全站仪数据比较,验证了算法的测量精度和有效性.  相似文献   
515.
In the recent years a considerable effort has been devoted to foster the understanding of the basic mechanisms underlying the dynamical arrest that is involved in glass forming in supercooled liquids and in the sol-gel transition. The elucidation of the nature of such processes represents one of the most challenging unsolved problems in the field of material science. In this context, two important theories have contributed significantly to the interpretation of these phenomena: the Mode-Coupling theory (MCT) and the Percolation theory (PT). These theories are rooted on the two pillars of statistical physics, universality and scale laws, and their original formulations have been subsequently modified to account for the fundamental concepts of Energy Landscape (EL) and of the universality of the fragile to strong dynamical crossover (FSC). In this review, we discuss experimental and theoretical results, including Molecular Dynamics (MD) simulations, reported in the literature for colloidal and polymer systems displaying both glass and sol-gel transitions. Special focus is dedicated to the analysis of the interferences between these transitions and on the possible interplay between MCT and PT. By reviewing recent theoretical developments, we show that such interplay between sol-gel and glass transitions may be interpreted in terms of the extended F13 MCT model that describes these processes based on the presence of a glass-glass transition line terminating in an A3 cusp-like singularity (near which the logarithmic decay of the density correlator is observed). This transition line originates from the presence of two different amorphous structures, one generated by the inter-particle attraction and the other by the pure repulsion characteristic of hard spheres. We show here, combining literature results with some new results, that such a situation can be generated, and therefore experimentally studied, by considering colloidal-like particles interacting via a hard core plus an attractive square well potential. In the final part of this review, scaling laws associated both to MCT and PT are applied to describe, by means of these two theories, the specific viscoelastic properties of some systems.  相似文献   
516.
The present work is a continuation of our translational research focusing on the use of silver nanoparticles (AgNPs) to solve the global problem of antibiotic resistance. In vivo fieldwork was done with 300 breeding farm cows with serous mastitis. Ex vivo assays revealed that after cow treatment with the antibiotic drug Spectromast LCTM, S. dysgalactiae susceptibility to 31 antibiotics dropped by 22.9%, but after treatment with Argovit–CTM AgNPs, it was raised by 13.1%. This was explained by the fact that the percentage of isolates with an efflux effect after Spectromast LC treatment resulted in an 8% increase, while Argovit-C-treatment caused a 19% decrease. The similarity of these results to our previous results on S. aureus isolates from mastitis cows treated with the antibiotic drug Lactobay and Argovit–CTM AgNPs was shown. So, mastitis treatments with Argovit-CTM AgNPs can partially return the activity of antibiotics towards S. dysgalactiae and S. aureus, while, in contrast, treatments with antibiotic drugs such as Spectromast LC and Lactobay enhance bacterial resistance to antibiotics. The results of this work strengthen the hope that in the future the use of AgNPs as efflux pump inhibitors will recover the activity of antibiotics, and thus will preserve the wide spectrum of antibiotics on the market.  相似文献   
517.
Universal Access in the Information Society - The interaction challenges presented by touch-screen enabled devices for blind and visually impaired people has been addressed extensively in the...  相似文献   
518.
Vegetable oils are very promising alternatives to fossil lubricants due to their abundance, low cost, excellent performance, and environmental friendliness. Due to its multifunctional structure, castor oil is an excellent precursor in the synthesis of new biolubricants. However, it showed poor thermal-oxidative stability and a higher pour point. This study used castor oil fatty acids prepared by transesterification (EHRO), epoxidation (TEPO), and oxirane ring opening with the aromatic amines aniline (ANIL) and p-anisidine (ANIS). The chemical structure of these oils was verified by 1H and 13C NMR analysis, and mass spectrometry. Measurements show that the presence of an aromatic amine increases the viscosity resulting in 172 (ANIL) and 199 (ANIS) cSt at 40°C, but reduces viscosity index to 16 and 1, respectively. In addition, the amine groups can scavenge radicals increasing their thermal and oxidative stability. These products do not oxidize copper, and tribological analysis reveals that ANIS has the lowest torque with wear equivalent to commercial mineral lubricant NH-140.  相似文献   
519.
Wind turbine (WT) reliability has come to the forefront of research due to the rapid growth of wind energy in recent years. Reliability information can help understand failure causes and focus maintenance and prevention efforts on the most critical components, reducing costs and increasing profits. This paper offers new insights into WT reliability after analysing the data provided by the Supervisory Control And Data Acquisition (SCADA) system collected from seven onshore WTs located in central Spain from January 2014 to September 2021. To this end, we propose a method to link SCADA data to failure and maintenance records based on checking whether each 10-min average time sample was collected when any failure or maintenance action had been reported. These records have been manually mapped to the WT taxonomy based on the standard Reference Designation System for Power Plants (RDS-PP®) with minor changes. We present three different results: (i) The capacity factor and time-based availability of each WT; (ii) the subsystem failure rate and downtime to identify the most critical ones; and (iii) each WT power curve with the 10-min time samples labelled as healthy, under maintenance, or failure states, along with a ranking of the subsystems causing the most failures in each part of the power curves. It is the first time that time samples are linked to failure and maintenance records to visualise their distribution on the power curves. These results can help research point in the right direction to improve reliability and increase electricity production worldwide.  相似文献   
520.
通过野外调查、标本鉴定和数据信息查询,对河北嶂石岩区域分布的野生油脂植物资源的种类、含油量及蕴藏量进行了统计和分析。结果表明:河北嶂石岩区域共有油脂植物39科72属79种,占嶂石岩区域植物总数的35.91%;在物种组成上,以唇形科、菊科、蔷薇科、十字花科和豆科为优势类群;在生活型上,以草本植物数量为多,木本植物较少,分别占油脂植物的51.90%和37.97%;在含油量上,以含油量在10%~20%之间的植物种类最多,另有近一半的植物含油量在30%以上;在油脂组成成分上,以富含亚油酸、亚麻酸等多不饱和脂肪酸的种类为主,占油脂植物的72.15%。唇形科、菊科、十字花科、豆科、松科和胡桃科等植物因蕴藏丰富、含油量高、应用前景广阔,可作为河北嶂石岩区域野生油脂植物优先开发的重点。  相似文献   
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