全文获取类型
收费全文 | 1867篇 |
免费 | 98篇 |
国内免费 | 7篇 |
专业分类
电工技术 | 25篇 |
综合类 | 2篇 |
化学工业 | 404篇 |
金属工艺 | 68篇 |
机械仪表 | 132篇 |
建筑科学 | 31篇 |
矿业工程 | 4篇 |
能源动力 | 83篇 |
轻工业 | 131篇 |
水利工程 | 12篇 |
石油天然气 | 4篇 |
武器工业 | 1篇 |
无线电 | 302篇 |
一般工业技术 | 384篇 |
冶金工业 | 113篇 |
原子能技术 | 21篇 |
自动化技术 | 255篇 |
出版年
2024年 | 1篇 |
2023年 | 40篇 |
2022年 | 39篇 |
2021年 | 78篇 |
2020年 | 57篇 |
2019年 | 73篇 |
2018年 | 61篇 |
2017年 | 58篇 |
2016年 | 79篇 |
2015年 | 51篇 |
2014年 | 113篇 |
2013年 | 143篇 |
2012年 | 131篇 |
2011年 | 144篇 |
2010年 | 93篇 |
2009年 | 98篇 |
2008年 | 93篇 |
2007年 | 98篇 |
2006年 | 77篇 |
2005年 | 50篇 |
2004年 | 50篇 |
2003年 | 45篇 |
2002年 | 21篇 |
2001年 | 38篇 |
2000年 | 23篇 |
1999年 | 25篇 |
1998年 | 43篇 |
1997年 | 24篇 |
1996年 | 19篇 |
1995年 | 12篇 |
1994年 | 9篇 |
1993年 | 16篇 |
1992年 | 12篇 |
1991年 | 3篇 |
1990年 | 5篇 |
1989年 | 9篇 |
1988年 | 4篇 |
1987年 | 6篇 |
1986年 | 3篇 |
1985年 | 4篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1981年 | 2篇 |
1977年 | 7篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1964年 | 1篇 |
1941年 | 1篇 |
排序方式: 共有1972条查询结果,搜索用时 10 毫秒
101.
We present a highly efficient algorithm for computing the minimum distance between two solids of revolution, each of which is defined by a planar cross-section region and a rotation axis. The boundary profile curve for the cross-section is first approximated by a bounding volume hierarchy (BVH) of fat arcs. By rotating the fat arcs around the axis, we generate the BVH of fat tori that bounds the surface of revolution. The minimum distance between two solids of revolution is then computed very efficiently using the distance between fat tori, which can be boiled down to the minimum distance computation for circles in the three-dimensional space. Our circle-based approach to the solids of revolution has distinctive features of geometric simplification. The main advantage is in the effectiveness of our approach in handling the complex cases where the minimum distance is obtained in non-convex regions of the solids under consideration. Though we are dealing with a geometric problem for solids, the algorithm actually works in a computational style similar to that of handling planar curves. Compared with conventional BVH-based methods, our algorithm demonstrates outperformance in computing speed, often 10–100 times faster. Moreover, the minimum distance can be computed very efficiently for the solids of revolution under deformation, where the dynamic reconstruction of fat arcs dominates the overall computation time and takes a few milliseconds. 相似文献
102.
Pham Huy Thong Florentin Smarandache Phung The Huan Tran Manh Tuan Tran Thi Ngan Vu Duc Thai Nguyen Long Giang Le Hoang Son 《计算机系统科学与工程》2023,46(2):1981-1997
Clustering is a crucial method for deciphering data structure and producing new information. Due to its significance in revealing fundamental connections between the human brain and events, it is essential to utilize clustering for cognitive research. Dealing with noisy data caused by inaccurate synthesis from several sources or misleading data production processes is one of the most intriguing clustering difficulties. Noisy data can lead to incorrect object recognition and inference. This research aims to innovate a novel clustering approach, named Picture-Neutrosophic Trusted Safe Semi-Supervised Fuzzy Clustering (PNTS3FCM), to solve the clustering problem with noisy data using neutral and refusal degrees in the definition of Picture Fuzzy Set (PFS) and Neutrosophic Set (NS). Our contribution is to propose a new optimization model with four essential components: clustering, outlier removal, safe semi-supervised fuzzy clustering and partitioning with labeled and unlabeled data. The effectiveness and flexibility of the proposed technique are estimated and compared with the state-of-art methods, standard Picture fuzzy clustering (FC-PFS) and Confidence-weighted safe semi-supervised clustering (CS3FCM) on benchmark UCI datasets. The experimental results show that our method is better at least 10/15 datasets than the compared methods in terms of clustering quality and computational time. 相似文献
103.
104.
Jong-Ho Lee Kwang Nyeon Kim Ji-Won Son Joosun Kim Byung-Kook Kim Hae-Weon Lee Jooho Moon 《Journal of Materials Science》2007,42(6):1866-1871
LSGM is known to have very serious interfacial reactivity with other unit cell components even though it is one of the most
favorable solid electrolytes for intermediate-temperature SOFCs. Above all, the formation of a La-deficient La-Sr-Ga-O phase
at the LSGM/NiO or the LSGM/CeO2 interface is most problematic in LSGM-based SOFCs due to the very resistive nature of its electrical property in fuel cell
operating conditions. In this study, we investigated the interfacial reactions in LSGM-based SOFCs under various fabrication
conditions, in order to discern a method to either avoid or diminish the undesirable influence of these interfacial reactions.
Microstructural evolution due to the chemical reactions between the anode and electrolyte layer were characterized with an
Environmental Scanning Electron Microscopy (ESEM-PHILIPS XL-30) and an Energy Dispersive X-ray (EDX-Link XL30) analysis. The
spatial distributions of each constituent element at the interfaces were thoroughly investigated with an Electron Probe Micro-Analyzer
(EPMA-JEOL. JXA-8600). 相似文献
105.
The use of Static Two Phase Locking Protocols (S2PL) for concurrency control in real-time database systems (RTDBS) has received little attention in the past. Actually, real-time S2PL (RT-S2PL) protocols do possess some desirable features making them suitable for RTDBS, especially for distributed real-time database systems (DRTDBS) in which remote locking is required and distributed deadlock is possible. In this paper, different RT-S2PL protocols are proposed. They differ in their methods of reducing the blocking time of higher priority transactions. Their performance is studied and compared with a real-time dynamic two phase locking protocol (RT-D2PL), called Hybrid Two Phase Locking (Hb2PL). The impact of different system and workload parameters, such as mean inter-arrival time of transactions, number of remote lock requests of a transaction, communication overhead for sending messages, and database size on their performance have been examined. The performance results indicate that the RT-S2PL protocols are suitable for DRTDBS in which the proportion of local locks of a transaction is small and the communication overhead for locking is high. 相似文献
106.
In Sik Yu Hyun Soo Woo Hyoung Il Son Woojin Ahn Hoeryong Jung 《Advanced Robotics》2013,27(18):2115-2143
This paper presents a new design and analysis of a haptic interface for a gastrointestinal endoscopy simulation. The gastrointestinal endoscopy is a procedure in which the digestive tract and organs of a patient are diagnosed and treated using a long and flexible endoscope. The developed haptic interface incorporates two degrees of freedom (DOF), each of which is necessary to describe the movements of an endoscope during the actual endoscopy procedures. The haptic interface has a translational motion mechanism to implement the insertion movement of the endoscope, and a rotational motion mechanism to implement the rotational movement of the endoscope. The endoscope included in the haptic interface is supported by a folding guide to prevent the endoscope from buckling. Force feedback in each direction is provided by wire-driven mechanisms. The developed haptic interface has a workspace, sensitivity, and maximum attainable force and torque enough to simulate the endoscopy procedures such as colonoscopy, upper GI (gastrointestinal) endoscopy, and endoscopic retrograde cholangiopancreatography (ERCP). The developed haptic interface is applied to implementation of a colonoscopy simulation. Performance including force bandwidth is evaluated through experiments and simulation. 相似文献
107.
Esfandyar Mazhari Jiayun Zhao Nurcin Celik Seungho Lee Young-Jun Son Larry Head 《Simulation Modelling Practice and Theory》2011,19(1):463-481
Unlike fossil-fueled generation, solar energy resources are geographically distributed and highly intermittent, which makes their direct control extremely difficult and requires storage units as an additional concern. The goal of this research is to design and develop a flexible tool, which will allow us to obtain (1) an optimal capacity of an integrated photovoltaic (PV) system and storage units and (2) an optimal operational decision policy considering the current and future market prices of the electricity. The proposed tool is based on hybrid (system dynamics model and agent-based model) simulation and meta-heuristic optimization. In particular, this tool has been developed for three different scenarios (involving different geographical scales), where PV-based solar generators, storage units (compressed-air-energy-storage (CAES) and super-capacitors), and grid are used in an integrated manner to supply energy demands. Required data has been gathered from various sources, including NASA and TEP (utility company), US Energy Information Administration, National Renewable Energy Laboratory, commercial PV panel manufacturers, and publicly available reports. The constructed tool has been demonstrated to (1) test impacts of several factors (e.g. demand growth, efficiencies in PV panel and CAES system) on the total cost of the integrated generation and storage system and an optimal mixture of PV generation and storage capacity, and to (2) demonstrate an optimal operational policy. 相似文献
108.
Jong Cheol Kim Dok Yol LeeHae-Ryoung Kim Hae-Weon LeeJong-Ho Lee Ji-Won Son 《Thin solid films》2011,519(8):2534-2539
The feasibility of employing a NiO-yttria stabilized zirconia (YSZ) nano-powder slurry spin coating (NSC) to fabricate a thin film (≤ 1 μm) electrolyte solid oxide fuel cell (TF-SOFC) on a relatively rough surface of the support is investigated in this study. The NiO-YSZ nano-powder with ~ 200 nm particle size was synthesized by a single-step glycine nitrate process and super-apex milling. Through varying the NiO-YSZ nano-powder slurry condition by changing polymeric additives, a leveled surface of the spin coated layer which enabled to overcome the surface roughness of the bulk ceramic processed anode substrate was obtained. On the NSC layer, TF-SOFC components with flat profiles could be fabricated using pulsed laser deposition. A stable open circuit voltage of 1.04 V was obtained with these thin film components on an anode support with a rough surface. 相似文献
109.
Safety-critical software systems such as certain nuclear instrumentation and control (NI&C) systems should be developed with thorough verification. This study presents a method of software requirement verification with a case study for a nuclear power plant (NPP) protection system. The verification introduces colored petri net (CPN) for system modeling and prototype verification system (PVS) for mathematical verification. In order to aid flow-through from modeling by CPN to mathematical proof by PVS, an information extractor from CPN models has been developed in this paper. In order to convert the extracted information to the PVS specification language, a translator has also been developed. This combined method has been applied to the functional requirements of the Wolsong NPP Shut Down System #2 (SDS2); logical properties of the requirements were verified. Through this research, guidelines and a tool support for the use of formal methods have been developed for application to NI&C software verification. 相似文献
110.
Yi-Joon Kim Sang-Un Lee Wa Gao Chung-Han Chung Chang-Woo Son Jin-Woo Lee 《Korean Journal of Chemical Engineering》2011,28(7):1580-1586
The optimal conditions of the downstream process for recovery of pullulan produced by Aureobasidium pullulans HP-2001 were examined using response surface method (RSM). The optimal amount of diatomite in filter press and the optimal flow rate in a continuous flow centrifuge for removal of cells from the culture broth of A. pullulans HP-2001 were found to be 5.0% (v/v) and 2.0 L/min. Based on central composite design (CCD) experiments and analysis of variance (ANOVA) indicated that the optimal conditions for recovery of pullulan from the supernatant by precipitation were the volume ratio of ethanol (or isopropanol) to supernatant of 3.0: 1.0, the reaction time of 29.5 h, and the reaction temperature of 20.2 °C. The expected maximal recovery yields of pullulan using ethanol and isopropanol under optimized conditions were 79.2 and 85.5%, respectively. 相似文献