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   320篇
  免费   25篇
  国内免费   1篇
电工技术   6篇
综合类   3篇
化学工业   84篇
金属工艺   3篇
机械仪表   20篇
建筑科学   7篇
能源动力   12篇
轻工业   61篇
水利工程   2篇
石油天然气   3篇
无线电   43篇
一般工业技术   57篇
冶金工业   14篇
自动化技术   31篇
  2024年   1篇
  2023年   3篇
  2022年   14篇
  2021年   19篇
  2020年   14篇
  2019年   13篇
  2018年   22篇
  2017年   11篇
  2016年   21篇
  2015年   9篇
  2014年   10篇
  2013年   36篇
  2012年   14篇
  2011年   22篇
  2010年   14篇
  2009年   13篇
  2008年   14篇
  2007年   13篇
  2006年   14篇
  2005年   8篇
  2004年   6篇
  2003年   6篇
  2002年   3篇
  2001年   2篇
  2000年   7篇
  1999年   3篇
  1998年   2篇
  1997年   4篇
  1996年   5篇
  1995年   1篇
  1994年   4篇
  1993年   1篇
  1992年   3篇
  1991年   1篇
  1990年   1篇
  1985年   2篇
  1984年   1篇
  1982年   1篇
  1981年   1篇
  1980年   1篇
  1979年   3篇
  1978年   1篇
  1975年   1篇
  1971年   1篇
排序方式: 共有346条查询结果,搜索用时 11 毫秒
131.
Height and body weight were measured in 2,284 subjects over 20 years old. The subjects were chosen by cluster sampling in 9 districts of Kelantan. Blood was drawn after an overnight fast for measurement of cholesterol (chol), triglyceride (TG), VLDL and HDL-Chol. Oral glucose tolerance test was performed with 75 g glucose. The overall prevalence of overweight [BMI (kg/m2) > or = 25-< or = 30] and obesity (BMI > 30) was 21.3% and 4.5% respectively. The overweight and obese were significantly younger than the lean subjects. The prevalence of hypercholesterolemia (chol > 5.2 mmol/l) in lean, overweight and obese subjects was 65.3%, 70.2% and 74.7%, respectively. Impaired glucose tolerance was found in 16.6% of the lean, 21.6% of the overweight and 32.0% of the obese subjects. Diabetes mellitus was found in 7.9% of the lean, 10.5% of the overweight and 6.7 of the obese subjects. 10.1% of lean, 13.2% of overweight and 23.3% of obese individuals were hypertensive. In conclusion, the high prevalence of overweight and obesity in Malaysia was associated with adverse lipid and glucose metabolism as well as poor blood pressure control.  相似文献   
132.
Malaysia aspires to be a fully industrialised nation by the year 2020. This has brought about a shift from what was predominantly an agriculturally-based economy to a rapidly expanding manufacturing-based one. This shift has brought to the fore the need for a large pool of people, especially engineers, with a strong base in science and technology. The government has embarked on various programmes to launch the bandwagon. This paper describes some of these programmes and measures that have been implemented or are now being planned, with a focus on engineering and engineering education at the tertiary level. Some recommendations are also made for supplementing the programmes already in place  相似文献   
133.
In a sequence of reactions, three different series of novel mono- and disarylazo pyrazolo(1,5-a)pyrimidine pigments were prepared to determine whether these products might successfully act as possible alternatives for benzidine-based dyestuffs, which are known to be associated with toxicological hazard and carcinogenic effects. The structure of the named compounds was inferred from elemental and spectral analysis and, in some cases, by alternative synthetic routes.  相似文献   
134.
In this paper we present a comparative study of two approaches for road traffic density estimation. The first approach uses the microscopic parameters which are extracted using both motion detection and tracking methods from a video sequence, and the second approach uses the macroscopic parameters which are directly estimated by analyzing the global motion in the video scene. The extracted parameters are applied to three classifiers, the K Nearest Neighbor (KNN) classifier, the LVQ classifier and the SVM classifier, in order to classify the road traffic in three categories: light, medium and heavy. The methods are compared based on their robustness to the classification of different road traffic states. The goal of this study is to propose an algorithm for road traffic density estimation with a high precision.  相似文献   
135.
A nonlinear H output feedback controller is proposed and coupled to a high-order sliding mode estimator to regulate an UAV in the presence of the unmatched perturbations. The plant to be controlled is a Quadrotor helicopter described by nonlinear dynamics with plant uncertainties due to the variations of inertia moments and payload operation. A robust state estimation is considered under model uncertainties as well as external/measurement disturbances. Performance issues of the controller are illustrated in a simulation study made for an UAV prototype.  相似文献   
136.
Journal of Mechanical Science and Technology - Electric chillers and thermal energy storage (TES) tanks are important equipment for gas district cooling plants. One feasible way of assessing the...  相似文献   
137.
Pattern Analysis and Applications - In this work, we propose a new formulation of the objects modeling combining geometry and appearance; it is useful for detection and recognition. The object...  相似文献   
138.
In this study, the effect of the voids growth on the damage of PP/talc micro-composite was analyzed using experimental and numerical approaches. Pure PP was filled with four proportions of treated talc: 5, 10, 40 and 50%. Tensile tests were performed on specimens manufactured from this composite. The Gurson–Tvergaard–Needleman model was implemented in FE model to predict the damage of the PP/talc. The predicted results were compared to the experimental ones. There is a good agreement between the numerical and the experimental results for pure PP, PP?+?40% of talc and the PP?+?50% of talc. We noted a significant divergence between the experimental and the numerical results for the PP reinforced with 5 and 10% of talc.  相似文献   
139.
Specimens of carbon steel (CS) and stainless steel (SS) 316 was joined together by double sided butt joint Friction Stir Welding method. Effect of the tool rotational speed and specimen preheat temperature on resultant microstructure and mechanical behavior was studied. Constant traveling speed of 100 mm/min, tool rotational speed of 500 and 1000 rpm in combination with preheat temperature of 50 and 100 °C was employed for this study. No sign of root crack was observed in all specimens. Optical microscopy identified four distinct zones characterized as the stir zone, thermal mechanically affected zone (TMAZ) in both SS and CS specimen, and heat affected zone (HAZ) in CS specimen. No HAZ in SS was observed. Scanning electron microscopy revealed formation of a thin void layer on several locations at the boundary between the TMAZ and the re-oriented region of SS side, while on the CS side no voids were identified. The grain size on the TMAZ of CS was observed to be smaller compared to the HAZ region. No sign of root crack was observed in all specimens. The specimens were subjected to U bend. Specimens joined with 1000 rpm rotational speed developed a brittle behavior and failed in U bend test. The extent of the crack and brittleness was proportional to the applied preheat. U bent specimens from 500 rpm rotation demonstrated a good stress corrosion cracking behavior in 30,000 ppm solution of sodium chloride (NaCl).  相似文献   
140.
NiTi shape memory alloy archwire is widely used in orthodontic treatment, replacing stainless steel for the flat and low deactivation force it can offer. However, the presence of friction at the contact region of wire and bracket may cause the low deactivation force to be ineffective to induce tooth movement. This work evaluated the bending deformation behavior of NiTi archwire in application using conventional orthodontic stainless steel bracket in levelling treatment. Experimental test rig was developed to perform three-brackets bending test at room temperatures (27 °C). The bracket used was 0.022-in stainless steel and the archwire was 0.016-in NiTi round wire. Fabricated polytetrafluoroethylene (Teflon) bracket was used as a control experiment to represent frictionless condition of deformation on three-bracket bending. Additionally, elastomeric ligature was also used to evaluate the effect of friction produced by the elastomer. Bending tests were done at 3 different deflection magnitudes of 2 mm, 3 mm and 4 mm. The results show that bending deformation behavior of the wire on frictionless Teflon bracket produced a flat force plateau on both activation and deactivation. On the other hand, when stainless steel brackets were used, the force plateau exhibited positive gradient on the activation and negative gradient on the deactivation.  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