首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   215篇
  免费   13篇
电工技术   4篇
化学工业   44篇
金属工艺   10篇
机械仪表   3篇
建筑科学   7篇
矿业工程   2篇
能源动力   5篇
轻工业   40篇
水利工程   2篇
无线电   8篇
一般工业技术   53篇
冶金工业   11篇
自动化技术   39篇
  2023年   2篇
  2022年   5篇
  2021年   7篇
  2020年   6篇
  2019年   3篇
  2018年   2篇
  2017年   13篇
  2016年   10篇
  2015年   8篇
  2014年   10篇
  2013年   24篇
  2012年   20篇
  2011年   22篇
  2010年   17篇
  2009年   10篇
  2008年   13篇
  2007年   10篇
  2006年   5篇
  2005年   2篇
  2004年   12篇
  2003年   4篇
  2002年   2篇
  2001年   1篇
  2000年   4篇
  1999年   2篇
  1998年   2篇
  1997年   1篇
  1996年   1篇
  1995年   2篇
  1992年   1篇
  1991年   1篇
  1983年   1篇
  1982年   2篇
  1977年   2篇
  1975年   1篇
排序方式: 共有228条查询结果,搜索用时 30 毫秒
101.
This paper presents the design and evaluation of a multi-lingual fingerspelling recognition module that is designed for an information terminal. Through the use of multimodal input and output methods, the information terminal acts as a communication medium between deaf and blind people. The system converts fingerspelled words to speech and vice versa using fingerspelling recognition, fingerspelling synthesis, speech recognition and speech synthesis in Czech, Russian and Turkish Languages. We describe an adaptive skin color based fingersign recognition system with a close to real-time performance and present recognition results on 88 different letters signed by five different signers, using more than four hours of training and test videos.  相似文献   
102.
In this paper, using the difference operator of order m and a lacunary sequence \(\theta = (k_{r})\), we introduce and examine some classes of sequences of fuzzy numbers. Furthermore, we study some of their properties like completeness, solidity, symmetricity and convergence free. We also give some inclusion relations related to these classes.  相似文献   
103.
Biosorption equilibrium, kinetics and thermodynamics of chromium(VI) ions onto cone biomass were studied in a batch system with respect to temperature and initial metal ion concentration. The biosorption efficiency of chromium ions to the cone biomass decreased as the initial concentration of metal ions was increased. But cone biomass of Pinus sylvestris Linn. exhibited the highest Cr(VI) uptake capacity at 45 degrees C. The biosorption efficiency increased from 67% to 84% with an increase in temperature from 25 to 45 degrees C at an initial Cr(VI) concentration of 300 mg/L. The Langmuir isotherm model was applied to experimental equilibrium data of Cr(VI) biosorption depending on temperature. According to Langmuir isotherm, the monolayer saturation capacity (Q(max)) is 238.10 mg/g. The pseudo-first-order and pseudo-second-order kinetic models were applied to test the experimental data for initial Cr(VI). The pseudo-second-order kinetic model provided the best correlation of the used experimental data compared to the pseudo-first-order kinetic model. The activation energy of biosorption (E(a)) was determined as 41.74 kJ/mol using the Arrhenius equation. Using the thermodynamic equilibrium coefficients obtained at different temperatures, the thermodynamic constants of biosorption (DeltaG(0), DeltaH(0) and DeltaS(0)) were also evaluated.  相似文献   
104.
The structural, optoelectronic and thermoelectric properties of Ca5Al2Sb6 under applied external pressures have been studied using the full potential linear augmented plane wave method. WIEN2k code is used with considering the generalized gradient approximation (GGA), modified Becke–Johnson (MBJ) and modified Becke–Johnson?+?spin orbit (mBJ?+?SO) functionals based on density functional theory (DFT). From electronic results, the size of the band gap decreases with increasing pressure and the nature of the band gap shift from direct to the indirect. In high pressure (>35.7 GPa by mBJ?+?SO), the band gap is also completely disappeared and the nature of compound is changed to the metallic. The calculated anisotropic optical properties such as the static dielectric function, increase with decreasing the size of band gap and increasing of pressure. As a novel result, the thermoelectric performance of n-type and p-type doping of Ca5Al2Sb6 is related to the value of pressure. According to the thermoelectric results, the n-type one has the highest ZT in comparison with the p-type Ca5Al2Sb6 material.  相似文献   
105.
106.
The well-ordered titanium dioxide (TiO2) nanotube array surfaces were formed at different voltages such as 20 V, 40 V, 60 V, 80 V and 100 V for 1 h on cp-Ti by anodic oxidation (AO) technique. And then, to improve crystallinity of the surface, heat treatment was applied at 450 °C for 1 h to all surfaces without any morphological changing. The surface and cross sectional morphology, elemental structure, phase composition, functional groups, roughness and thickness, wettability and mechanical results were investigated by SEM, EDX, XRD, FT-IR, AFM, contact angle measurement device and nanoindentation tester, respectively. Mainly, anatase- and rutile-TiO2 phases were obtained at post-heat treatment whereas only, Ti phase was detected on AO surfaces at pre-heat treatment. All nanotube structures and the elements of Ti and O were uniformly distributed through the whole surface. The roughness and thickness of tube structures usually increased with increasing voltage values and measured. The roughness and thickness values were measured as 10.67–111.97 nm and 0.21–1.92 μm, respectively. TiO2 nanotube surfaces exhibited hydrophobic behaviors with respect to plain Ti surface. Furthermore, mechanical properties such as hardness and elastic modulus of the coating produced at minimum voltage were great compared to ones at higher voltage and plain Ti surface under a Berkovich indenter due to phase structure, homogeneity and density of nanotube structures.  相似文献   
107.
For manufacturing industries, financial performance evaluation is very important in a highly competitive environment. Therefore, an accurate and appropriate performance evaluation is critical. As financial performance indicators reflect the competitiveness of a company, they must be carefully identified in the evaluation process. Generally, traditional accounting-based financial performance (AFP) measures are used for performance evaluation. However, these measures are not sufficient for performance evaluation solely in the modern industry time. So, value-based financial performance (VFP) measures have recently been introduced to express the company value. In this paper, we propose a new financial performance evaluation approach to rank the companies of each sector in the Turkish manufacturing industry. For this purpose, a hierarchical financial performance evaluation model is structured based on the AFP and VFP main-criteria and their sub-criteria. We use fuzzy analytic hierarchy process (FAHP) to determine the weights of the criteria. The companies are ranked according to their own manufacturing sector by using TOPSIS and VIKOR comparatively. The results show that the obtained ranks of the companies by these methods are almost same with respect to their own sectors.  相似文献   
108.
Coenzyme Q10 (CoQ10) supplementation has been shown to improve diastolic heart function in various patient cohorts. Systolic and diastolic dysfunctions are common in patients with end‐stage renal disease. Favorable effects of CoQ10 on cardiac functions are yet to be seen in hemodialysis patients. We aimed to evaluate effect of CoQ10 supplementation on diastolic function in a cohort of maintenance hemodialysis patients. This was a prospective, double‐blind, placebo‐controlled, crossover study in which all patients received placebo and oral CoQ10 200 mg/d during the 8 weeks in each phase, with a 4‐week washout period. Participants underwent conventional and tissue Doppler echocardiography before and after each study phase. Parameters characterizing left ventricle diastolic function and other standard echocardiographic measurements were recorded. Twenty‐eight patients were randomized, but 22 patients completed study protocol. Intraventricular septum (IVS) thickness and left ventricle mass were significantly decreased in CoQ10 group (P = 0.03 and P = 0.01, respectively). Myocardial peak systolic and early diastolic velocities derived from IVS were significantly increased (P = 0.048 and P = 0.04, respectively). Isovolumetric relaxation time and E/Em ratio calculated for IVS also significantly reduced in CoQ10 group (p = 0.02 and p = 0.04, respectively). There was no significant difference in any of the studied echocardiographic parameters in placebo group. The results of this study showed that CoQ10 supplementation did not significantly improved diastolic heart functions compared with placebo in maintenance hemodialysis patients.  相似文献   
109.
In this study, two kinds of melt-processed YBCO samples with Y2O3 addition were fabricated and their microstructures were defined by XRD analysis and polarized light optical microscopy. The mechanical properties of these compounds have been investigated by measuring the Vickers hardness. The superconducting transition temperature was determined by inductive measurements for oxygenated and non-oxygenated samples. The compacted powders were located on a crucible with a buffer layer of Y2O3 and a crucible with Y2O3 powder freely poured to avoid liquid to spread on the furnace plate. It was found that the sample located on crucible with freely poured Y2O3 powder has shown almost single crystal and indicated a very sharp transition curve.  相似文献   
110.
Phenolic compounds (gallic acid, ellagic acid and quercetin) and carotenoids (??-carotene and retinol) were used to evaluate effects of antioxidant on refined hazelnut oil. Peroxide value (PV), free fatty acid (FFA), iodine value (IV) and color analysis were made on hazelnut oil 120?days stored in the 40?°C, light and airy condition. In oil sample PV were found at range of 78.1?C621.5 (meqO2/kg oil) in the end 120?days. Antioxidant effectiveness in hazelnut oil at the half of the storage period (60th day) was in the order: Quercetin?>???-carotene?=?gallic acid?>?ellagic acid. Antioxidative effectiveness was not observed in retinol treatment. However, FFA and IVs were determined in the range of 0.65?C0.86 (% as oleic acid) and 68?C85, respectively, at final storage.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号