全文获取类型
收费全文 | 785篇 |
免费 | 34篇 |
国内免费 | 3篇 |
专业分类
电工技术 | 14篇 |
综合类 | 1篇 |
化学工业 | 150篇 |
金属工艺 | 19篇 |
机械仪表 | 21篇 |
建筑科学 | 40篇 |
矿业工程 | 1篇 |
能源动力 | 70篇 |
轻工业 | 60篇 |
水利工程 | 8篇 |
石油天然气 | 6篇 |
无线电 | 97篇 |
一般工业技术 | 158篇 |
冶金工业 | 12篇 |
原子能技术 | 3篇 |
自动化技术 | 162篇 |
出版年
2024年 | 3篇 |
2023年 | 16篇 |
2022年 | 52篇 |
2021年 | 76篇 |
2020年 | 28篇 |
2019年 | 37篇 |
2018年 | 45篇 |
2017年 | 41篇 |
2016年 | 29篇 |
2015年 | 27篇 |
2014年 | 30篇 |
2013年 | 74篇 |
2012年 | 29篇 |
2011年 | 37篇 |
2010年 | 30篇 |
2009年 | 31篇 |
2008年 | 29篇 |
2007年 | 23篇 |
2006年 | 21篇 |
2005年 | 13篇 |
2004年 | 16篇 |
2003年 | 17篇 |
2002年 | 14篇 |
2001年 | 8篇 |
2000年 | 13篇 |
1999年 | 11篇 |
1998年 | 8篇 |
1997年 | 8篇 |
1996年 | 9篇 |
1995年 | 5篇 |
1994年 | 3篇 |
1993年 | 7篇 |
1992年 | 2篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 1篇 |
1988年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 2篇 |
1981年 | 3篇 |
1979年 | 2篇 |
1977年 | 1篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1963年 | 1篇 |
排序方式: 共有822条查询结果,搜索用时 15 毫秒
11.
In this work, wire antennas are designed to jam GSM frequencies using genetic algorithms. These antennas are designed to block communication at 3-band GSM frequencies. They are planned to be mounted on a vehicle and therefore are modeled on a ground plane. Jammer antennas designed in this work are composed of wires, placed on two square dielectric frames, perpendicular to each other. Genetic optimization routines are developed on MATLAB environment for the designs carried out in this work. Electromagnetic simulation program called SuperNEC, which analyses antennas by the method of moments, is used to determine the antenna performances and is called by the developed GA routines. The purpose of the antenna optimization is to obtain low VSWR values and omni-directional radiation pattern near ground at θ = [70° 80° 90°] planes at all GSM frequencies, since the targets will be near ground for this application. Original and interesting antenna designs are obtained as the result of genetic optimization, and are presented in the paper. 相似文献
12.
Distributed uplink scheduling in OFDMA systems is considered. In the proposed model, mobile terminals have the responsibility of making their own transmission decisions. The proposed scheme is based on two dimensional reservation in time and frequency. Terminals use channel state information in order to favor transmissions over certain subchannels, and transmission is done in a probabilistic manner. The proposed approach provides more autonomy to mobile devices in making transmission decisions. Furthermore, it allows avoiding collisions during transmission since it leads to collision detection during the resource reservation phase. The proposed approach is compared to other random access methods and shown to be superior in terms of increasing sum-rate, reducing the number of users in outage, and reducing the collision probability in the reservation phase. 相似文献
13.
Generalized queries are defined as sets of clauses in implication form. They cover several tasks of practical importance for database maintenance such as answering positive queries, computing database completions and integrity constraints checking. We address the issue of answering generalized queries under the minimal model semantics for the class of disjunctive deductive databases (DDDBs). The advanced approach is based on having the query induce an order on the models returned by a sound and complete minimal model generating procedure. We consider answers that are true in all and those that are true in some minimal models of the theory. We address the issue of answering positive queries through the construction of the minimal model state of the DDDB, using a minimal model generating procedure. The refinements allowed by the procedure include isolating a minimal component of a disjunctive answer, the specification of possible updates to the theory to enable the derivability of certain queries and deciding the monotonicity properties of answers to different classes of queries. 相似文献
14.
Özcan Özyurt Hacer Özyurt Adnan Baki Bülent Güven Hasan Karal 《Expert systems with applications》2012,39(15):12092-12104
The purpose of this study is to design a personalized adaptive and intelligent web based tutoring system based on learning style and expert system named UZWEBMAT and to evaluate its effects on 10th grade students’ learning of the unit of probability. In the study, initially, learning objects were prepared in three different ways in relation to three sub-learning areas of Visual–Auditory–Kinesthetic (VAK) learning style for each subject of the probability unit. These were appropriate for secondary school mathematics curricula. Then, they were transferred into the digital environment. Each student’s dominant learning style determines the content to which s/he will be directed since s/he is directed to the content that is appropriate for his/her learning style. The course to be followed by the students within UZWEBMAT and their browsing around the pages are decided by expert system integrated into the system. This expert system sets the situations in which s/he will get solution supports and the course s/he will follow in accordance with the performance of the student. Hereby, each student may follow a different course, and the solution supports s/he will get may also differ highlighting the individual learning. The sample of the study consists of 81 10th grade students and 3 mathematics teachers from two high schools in Trabzon, Turkey. Qualitative data were obtained both from the teachers and students participating in the study in order to answer the research questions about the implementation and evaluation of UZWEBMAT for mathematics teaching in a high school classroom. Obtained data were analyzed using qualitative data analysis methods. According to the results of the present study, positive opinions of students and teachers such as taking into account the individual learning differences and deriving mathematical relations and formulas through exploration became prominent. In addition, there were also other positive opinions of students and teachers such as providing permanent learning and introducing learning responsibility to the students. In this sense, it was concluded that UZWEBMAT is a beneficial instrument for both students and teachers. 相似文献
15.
SATCHMORE was introduced as a mechanism to integrate relevancy testing with the model-generation theorem prover SATCHMO. This
made it possible to avoid invoking some clauses that appear in no refutation, which was a major drawback of the SATCHMO approach.
SATCHMORE relevancy, however, is driven by the entire set of negative clauses and no distinction is accorded to the query
negation. Under unfavorable circumstances, such as in the presence of large amounts of negative data, this can reduce the
efficiency of SATCHMORE. In this paper we introduce a further refinement of SATCHMO called SATCHMOREBID: SATCHMORE with BIDirectional
relevancy. SATCHMOREBID uses only the negation of the query for relevancy determination at the start. Other negative clauses
are introduced on demand and only if a refutation is not possible using the current set of negative clauses. The search for
the relevant negative clauses is performed in a forward chaining mode as opposed to relevancy propagation in SATCHMORE which
is based on backward chaining. SATCHMOREBID is shown to be refutationally sound and complete. Experiments on a prototype SATCHMOREBID
implementation point to its potential to enhance the efficiency of the query answering process in disjunctive databases.
Donald Loveland, Ph.D.: He is Emeritus Professor of Computer Science at Duke University. He received his Ph.D. in mathematics from New York University
and taught at NYU and CMU prior to joining Duke in 1973. His research in automated deduction includes defining the model elimination
proof procedure and the notion of linear resolution. He is author of one book and editor/co-editor of two other books on automated
theorem proving. He has done research in the areas of algorithms, complexity, expert systems and logic programming. He is
an AAAI Fellow, ACM Fellow and winner of the Herbrand Award in Automated Reasoning.
Adnan H. Yahya, Ph.D.: He is an associate professor at the Department of Electrical Engineering, Birzeit University, Palestine. He received his
Diploma and PhD degrees from St. Petersburg Electrotechnical University and Nothwestern University in 1979 and 1984 respectively.
His research interests are in Artificial Intelligence in general and in the areas of Deductive Databases, Logic Programming
and Nonmonotonic Reasoning in particular. He had several visiting appointments at universities and research labs in the US,
Germany, France and the UK. Adnan Yahya is a member of the ACM, IEEE and IEEE Computer Society. 相似文献
16.
Mohammad Al-Rousan Author Vitae Adnan Shaout Author Vitae 《Computers & Electrical Engineering》2004,30(4):309-329
This paper introduces a new closed-form solution for the reliability of large-scale multiprocessor systems. The systems are based on SCI rings interconnected in hierarchical structures. Reliability expressions using enumeration technique are derived assuming Weibull failure process. The reliability function derived in this paper is general and valid for any hierarchical ring-based system with arbitrary number of levels. The hierarchical interconnections are constructed from self-healing rings and basic rings. The analysis shows the improvement achieved in reliability when self-healing rings are used. Although we used hierarchical systems based on SCI rings, the technique followed in this work is applied for any type of rings such as slotted or token rings. 相似文献
17.
Kashif Iqbal Sagheer Abbas Muhammad Adnan Khan Atifa Athar Muhammad Saleem Khan Areej Fatima Gulzar Ahmad 《计算机、材料和连续体(英文)》2021,66(2):1595-1613
The rapid development and progress in deep machine-learning techniques have become a key factor in solving the future challenges of humanity. Vision-based target detection and object classification have been improved due to the development of deep learning algorithms. Data fusion in autonomous driving is a fact and a prerequisite task of data preprocessing from multi-sensors that provide a precise, well-engineered, and complete detection of objects, scene or events. The target of the current study is to develop an in-vehicle information system to prevent or at least mitigate traffic issues related to parking detection and traffic congestion detection. In this study we examined to solve these problems described by (1) extracting region-of-interest in the images (2) vehicle detection based on instance segmentation, and (3) building deep learning model based on the key features obtained from input parking images. We build a deep machine learning algorithm that enables collecting real video-camera feeds from vision sensors and predicting free parking spaces. Image augmentation techniques were performed using edge detection, cropping, refined by rotating, thresholding, resizing, or color augment to predict the region of bounding boxes. A deep convolutional neural network F-MTCNN model is proposed that simultaneously capable for compiling, training, validating and testing on parking video frames through video-camera. The results of proposed model employing on publicly available PK-Lot parking dataset and the optimized model achieved a relatively higher accuracy 97.6% than previous reported methodologies. Moreover, this article presents mathematical and simulation results using state-of-the-art deep learning technologies for smart parking space detection. The results are verified using Python, TensorFlow, OpenCV computer simulation frameworks. 相似文献
18.
Hybrid Paper–Plastic Microchip for Flexible and High‐Performance Point‐of‐Care Diagnostics 下载免费PDF全文
Mohamed Shehata Draz Maryam Moazeni Manasa Venkataramani Harini Lakshminarayanan Ecem Saygili Nivethitha Kota Lakshminaraasimulu Kamyar Mehrabi Kochehbyoki Manoj Kumar Kanakasabapathy Shirin Shabahang Anish Vasan Mohamad Ali Bijarchi Adnan Memic Hadi Shafiee 《Advanced functional materials》2018,28(26)
A low‐cost and easy‐to‐fabricate microchip remains a key challenge for the development of true point‐of‐care (POC) diagnostics. Cellulose paper and plastic are thin, light, flexible, and abundant raw materials, which make them excellent substrates for mass production of POC devices. Herein, a hybrid paper–plastic microchip (PPMC) is developed, which can be used for both single and multiplexed detection of different targets, providing flexibility in the design and fabrication of the microchip. The developed PPMC with printed electronics is evaluated for sensitive and reliable detection of a broad range of targets, such as liver and colon cancer protein biomarkers, intact Zika virus, and human papillomavirus nucleic acid amplicons. The presented approach allows a highly specific detection of the tested targets with detection limits as low as 102 ng mL?1 for protein biomarkers, 103 particle per milliliter for virus particles, and 102 copies per microliter for a target nucleic acid. This approach can potentially be considered for the development of inexpensive and stable POC microchip diagnostics and is suitable for the detection of a wide range of microbial infections and cancer biomarkers. 相似文献
19.
In this study, an innovative adaptive and intelligent web based e-learning system, UZWEBMAT (Turkish abbreviation of Adaptive and INtelligent WEB based MAThematics teaching–learning system) was designed, developed and implemented. This e-learning system was intended for learning and teaching secondary school level permutation-combination-binomial expansion and probability subjects. Content which was prepared according to Turkish curriculum for secondary school mathematics course was transformed into learning objects in three different ways in accordance with VAK (Visual–Auditory–Kinesthetic) learning styles. Primary/secondary/tertiary learning styles of learners registering the system are determined and each learner receives the content appropriate for his/her dominant learning style. Also, they can be directed to contents of other styles according to their performances thanks to an expert system. Learning objects constituting the content were prepared according to constructivist approach. An active role for the learner was the purpose. Tips and intelligent solution supports within the learning objects were presented with expert system support to the learners. With this structure, UZWEBMAT bears the characteristics of intelligent tutoring system as well as an adaptive e-learning environment. All the movements of learners studying with UZWEBMAT are recorded and the necessary information is reported to both learners and teachers in a visualized way. 相似文献
20.
Sener Dikmese Adnan Kavak Kerem Kucuk Suhap Sahin Ali Tangel 《Wireless Personal Communications》2011,57(2):233-253
For the integration of smart antennas into third generation code division multiple access (CDMA) base stations, it still remains as a challenging task to implement smart antenna algorithms on programmable processors. In this paper, we study implementations of some CDMA compatible beamforming algorithms, namely least mean square (LMS), constant modulus (CM), and space code correlator (SCC) algorithms, using Xilinx??s Virtex family FPGAs. This study exhibits feasibility of implementing even simple, practical, and computationally small algorithms based on today??s most powerful FPGA technologies. 16 and 32 bits floating point implementations of the algorithms are investigated using both Virtex II and Virtex IV FPGAs. CDMA2000 reverse link baseband signal format is used in the signal modeling. Randomly changing fading and Direction-of-arrivals (DOAs) of multipaths are considered as a channel condition. The implementation results in terms of beamforming accuracy, FPGA resource utilization, weight vector computation time, and DOA estimation error are presented. Beamformer weight vectors using LMS and CM can be computed within less than 20 ??s on Virtex II FPGA and 10 ??s on Virtex IV FPGA, and using SCC it can be achieved within less than 22 ??s on Virtex IV FPGA. These results show that FPGAs provide approximately 500 times faster speed in implementations than our previous work with DSPs. 相似文献