全文获取类型
收费全文 | 681篇 |
免费 | 50篇 |
国内免费 | 1篇 |
专业分类
电工技术 | 10篇 |
综合类 | 1篇 |
化学工业 | 172篇 |
金属工艺 | 11篇 |
机械仪表 | 60篇 |
建筑科学 | 12篇 |
矿业工程 | 1篇 |
能源动力 | 25篇 |
轻工业 | 79篇 |
水利工程 | 2篇 |
无线电 | 133篇 |
一般工业技术 | 126篇 |
冶金工业 | 27篇 |
原子能技术 | 5篇 |
自动化技术 | 68篇 |
出版年
2024年 | 3篇 |
2023年 | 7篇 |
2022年 | 20篇 |
2021年 | 21篇 |
2020年 | 28篇 |
2019年 | 25篇 |
2018年 | 33篇 |
2017年 | 36篇 |
2016年 | 33篇 |
2015年 | 18篇 |
2014年 | 16篇 |
2013年 | 50篇 |
2012年 | 41篇 |
2011年 | 73篇 |
2010年 | 32篇 |
2009年 | 44篇 |
2008年 | 34篇 |
2007年 | 27篇 |
2006年 | 29篇 |
2005年 | 28篇 |
2004年 | 17篇 |
2003年 | 13篇 |
2002年 | 16篇 |
2001年 | 5篇 |
2000年 | 8篇 |
1999年 | 9篇 |
1998年 | 11篇 |
1997年 | 9篇 |
1996年 | 12篇 |
1995年 | 10篇 |
1994年 | 3篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1979年 | 1篇 |
1976年 | 2篇 |
1972年 | 1篇 |
排序方式: 共有732条查询结果,搜索用时 0 毫秒
101.
Detecting the wheel pattern of a vehicle using stereo images 总被引:1,自引:0,他引:1
This paper presents a method for detecting the wheels of a vehicle in stereo image pairs. The method consists of two steps: (i) geometrical transformation; and (ii) circle extraction. The geometrical transformation uses the disparity values obtained from a stereo image pair to calculate the parameters of the plane containing wheels of the vehicle. By using these parameters, we transform any elliptical wheels contained in the plane to circular ones which can be extracted by the circle extraction algorithm. The circle extraction algorithm consists of (1) template matching and (2) Hough transform. In order to save computation and improve the results in the Hough transform, we employ two constraints (a) the neighbor-region edge connectivity and (b) the gradient direction of each edge point, to eliminate non-circular edge points. Experimental results show that these two constraints do eliminate non-circular edge points and preserve any circle embedded in edges. From the final results, we can observe that our method can detect and locate the wheels of a vehicle successfully. 相似文献
102.
Jong Gu Kang Gyeong Su Ryu Dong Cheol Kim Mun Jin Kang Young Whan Park Sehun Rhee 《Journal of Mechanical Science and Technology》2013,27(2):501-509
The wire feeding system for gas metal arc welding usually consists of a wire feeder and a torch. In many industries, the distance between the wire feeder and the torch is generally 3 m to 5 m. In a conventional wire feeder, a direct current (DC) motor is used for wire feeding. However, a significant problem with this system is the impossibility of feedback control because of inner or outer impedance. In this paper, a digital wire feeder was developed by using a DC encoder motor and a push-pull torch. An optimized wire-feeding system was also developed by experiment. The welding process was observed using a high-speed camera. The resulting wire-feeding system exhibits low spatter generation and arc stability. 相似文献
103.
Se‐Hee Jo Jeung Kun Kim Chang Geun Yoo Jin‐Il Kim Yoon‐Mo Koo Sunyong Mun 《加拿大化工杂志》2007,85(6):874-882
A ternary separation usually requires the use of two simulated moving bed (SMB) units in series. Since an increase in the number of SMB units leads to a significant increase in capital and operational costs, the use of a single SMB unit is preferred if its structure can be modified to treat a ternary separation. Such a modified single SMB unit has been typified by a five‐zone SMB or a two‐zone SMB so far. The separation performances‐of a five‐zone SMB and a two‐zone SMB are compared in this paper by using the ternary amino acid mixture as a model system. A five‐zone SMB is designed with the safety margin method while a two‐zone SMB is optimized using genetic algorithm. A five‐zone SMB based on the maximum allowable safety margin, although it may not guarantee the global optimum solution, results in much better separation performance than a two‐zone SMB at its global optimum state. 相似文献
104.
Sang-Yoon Park Lee Hi-Koan Yang Gyun-Eui Mun Sang-Don 《International Journal of Precision Engineering and Manufacturing》2010,11(2):195-200
In this paper it was suggested the machining method that can improve machining accuracy and reduce the machining time applying
the formed tools based on the rotor shape feature to finishing machining for efficient machining of asymmetric rotors. For
machining the complicated asymmetric rotor profile, machining area is divided and formed tools are manufactured based on the
rotor feature., and the efficient machining method of screw motor was proposed using the formed tools and four axis machining
devices. With the suggested machining method, machining time could be reduced compared to the general end mill machining method,
and the machining errors of the proposed method could be within the allowable tolerance of the product so as to carry out
the precise machining. 相似文献
105.
Ki-Young Shin Yong Hoon Rim Youn Soo Kim Hyo Shin Kim Jae Woong Han Chang Hyun Choi Kyung Suk Lee Joung Hwan Mun 《Journal of Mechanical Science and Technology》2010,24(9):1901-1909
Gait analysis using 3D motion capture systems provides joint kinematic and kinetic analysis results such as joint relative angles and moments that can be use used to evaluate the degrees of pathological gait patterns. However, the complex data produced using these 3D motion capture systems can only analyzed by experts, because the gait analysis is highly coupled to the kinematics of each joint. Therefore, several Several previous studies using gait analysis have relied on the data compression technique to represent gait deviation from the average normal profiles as a single value. Even though it is important to evaluate gait pathologies at the joint level, all these previous studies have just used a single value to evaluate the pathological gait pattern. Using just one variable for evaluation of a gait is limited in terms of determining which joint movement patterns are getting better during rehabilitation. Therefore, in this study, a method suitable for evaluating gait deviation during a gait was developed to provide three indices for the hip, knee and ankle joints. In addition, to validate the proposed method in clinical cases, experimental tests were conducted on thirty thirty-six normal walkers and six patients with cerebral palsy. Furthermore, to validate the proposed method in regards to rehabilitation, experimental tests were conducted on three classified walking groups with imposed ankle equinus constraints. The JNI for the hip joint, knee joint and ankle were 8.78 (±3.70), 2.92 (±3.25) and 8.79 (±4.38), respectively, in the normal walking group. However, these values were significantly different for the pathological walking group with cerebral palsy. The JNI of the hip joint, knee joint and ankle joint were 203.73 (±171.59), 81.23 (±52.13) and 248.39 (±149.99), respectively, for this group. There were also differences between any two of the three classified groups with imposed ankle equinus constraints. In particular, the JNI of the ankle joint was statistically different at the p<0.01 level, and this parameter clearly increased as the degree of the imposed ankle equinus was increased. These results demonstrate that the proposed JNI can be used as a scalar factor to evaluate the angular deviation of each joint in normal and patient groups. In addition, this approach can be adapted to evaluate rehabilitation and pre/post surgery. 相似文献
106.
This paper describes the effect of lime on composite hot-mix asphalt (HMA) mixtures of aggregate and asphalt binder evaluated using viscoelastic continuum damage analysis, which is based on predicting the effective stress vs. strain equations and microcrack growth. The performance characteristics evaluated in this study included fatigue cracking and rutting resistance in both moisture-damaged and undamaged states. The test methods used in this evaluation were the dynamic modulus test for stiffness characterization, the direct tension test for fatigue cracking characterization, and the triaxial repeated-load permanent deformation test for rutting characterization. The main contribution of this paper is the demonstration of advanced test methods and models that can be used to evaluate the performance of various mixtures with respect to the fatigue damage and rutting performance. 相似文献
107.
108.
Cheong Ai Mun Tan Zu Wen Patrick Nwabueze Okechukwu Tan Chin Ping Lim Yang Mooi Nyam Kar Lin 《Food science and biotechnology》2018,27(4):1175-1184
Food Science and Biotechnology - Kenaf seed oil-in-water nanoemulsions (KSON) and kenaf seed oil-in-water macroemulsions were produced to access their gastroprotective effect against indomethacin-... 相似文献
109.
Zinc oxide (ZnO) nanoparticles were synthesized sonochemically by applying ultrasonic irradiation to a mixed aqueous-alcoholic solution of zinc nitrate with sodium hydroxide at room temperature. The morphology and optical properties of the ZnO nanoparticles were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and UV-vis spectroscopy. The C60(O)n nanoparticles were synthesized by heating a mixture of C60 and 3-chloroperoxybenzoic acid in a benzene solvent under the reflux system. The heated C60(O)n-ZnO nanocomposite was synthesized in an electric furnace at 700 degrees C for two hours. The heated C60(O)n-ZnO nanocomposite was characterized by XRD, SEM, and TEM, and examined as a catalyst in the photocatalytic degradation of organic dyes by UV-vis spectroscopy. The photocatalytic effect of the heated C60(O)n-ZnO nanocomposite was evaluated by a comparison with that of unheated C60(O)n nanoparticles, heated C60(O)n nanoparticles, and unheated C60(O)n-ZnO in organic dyes, such as methylene blue (MB), methyl orange (MO), and rhodamine B (RhB) under ultraviolet light at 365 nm. 相似文献
110.
Kim S Shin DO Choi DG Jeong JR Mun JH Yang YB Kim JU Kim SO Jeong JH 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(10):1563-1569
A highly efficient, ultralarge-area nanolithography that integrates block-copolymer lithography with single-step ZnO nanoimprinting is introduced. The UV-assisted imprinting of a photosensitive sol-gel precursor creates large-area ZnO topographic patterns with various pattern shapes in a single-step process. This straightforward approach provides a smooth line edge and high thermal stability of the imprinted ZnO pattern; these properties are greatly advantageous for further graphoepitaxial block-copolymer assembly. According to the ZnO pattern shape and depth, the orientation and lateral ordering of self-assembled cylindrical nanodomains in block-copolymer thin films could be directed in a variety of ways. Significantly, the subtle tunability of ZnO trench depth enabled by nanoimprinting, generated complex hierarchical nanopatterns, where surface-parallel and surface-perpendicular nanocylinder arrays are alternately arranged. The stability of this complex morphology is confirmed by self-consistent field theory (SCFT) calculations. The highly ordered graphoepitaxial nanoscale assembly achieved on transparent semiconducting ZnO substrates offers enormous potential for photonics and optoelectronics. 相似文献