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排序方式: 共有445条查询结果,搜索用时 15 毫秒
41.
Zülküf Genç Umar H. Rizvi Ertan Onur Ignas Niemegeers 《Wireless Personal Communications》2010,53(3):349-364
The basic idea behind cooperative communications is that mobile terminals collaborate to send data to each other. This effectively
adds diversity in the system and improves the overall performance. In this paper, we investigate the potential gains of cooperative
communication in future home networks. We derive analytical expressions for the error probability of binary phase shift keying
(BPSK) signals over Nakagami-m fading channels in a multi relay communication network. Following to the analytical study, we analyze the contribution of
cooperative relaying to the 60GHz network connectivity through simulations using a realistic indoor environment model. We
compare the performance of different relay configurations under variable obstacle densities. We show that a typical 60GHz
indoor network should employ either a multi-relay configuration or a single-relay configuration with a smart relay selection
mechanism to achieve acceptable outage rates. In the use of multiple-relay configuration, both analytical and simulation studies
indicate that increasing the number of cooperative relays does not improve the system performance significantly after a certain
threshold. 相似文献
42.
Tuğçe P. Öztürk Onur B. Özdemir Ali Gelir Nahid A. Keshtiban Önder Yargı Selin Pıravadılı Mucur Alper Seçgin 《应用聚合物科学杂志》2024,141(4):e54854
Solid-state electrolytes such a further novel finding is going to have great importance because of the disadvantages of liquid electrolytes such as electrochemical instability, low ion selectivity, and interface contact. It is anticipated that the use of solid-state electrolytes including supercapacitors (SCs) will become widespread with decreasing self-leakage and environmental damage more than liquid electrolytes. In this study, SCs with graphene/PEDOT: PSS coated electrodes and binary PVA gel electrolytes with a conductive layer were designed and the electrochemical performance of the configurations was characterized. The effects of the conductive layer between binary electrolytes and the concentration of the KOH solution in the electrolytes were studied. It was observed that the conductive layer used between the gel electrolytes causes additional charging at the electrolyte/conductive layer interface and behaves like a serially connected capacitor to the double-layer capacitor. Interestingly, at a slow sweep rate (5 mV/s), the specific capacitance values of the assembled SCs decreased when a conductive layer was used but it increased when the sweep rate was fast (100 mV/s). 相似文献
43.
Nazmi Izli Gökcen Izli Onur Taskin 《Sensing and Instrumentation for Food Quality and Safety》2017,11(1):64-74
This study analysed the convective (60, 70 and 80° C), microwave (120 and 350 W) and freeze drying methods in terms of their effects on the drying characteristics, colour, total phenolic content (TPC) and antioxidant capacity of kiwi slices. Nine different mathematical models were applied to experimental data to achieve the most accurate calculation for drying curves. The Midilli et al. and Wang and Singh models proved to be the most suitable at explaining the drying kinetics of kiwi samples as compared to other models according to the statistical tests. Each drying method was significantly affected by colour parameters (L*, a*, b*, C, α and ΔE). The dried samples exhibited respectively 5–49 % and 10–47 % less TPC and antioxidant capacity compared to the fresh sample. According to the correlation analysis conducted between TPC and antioxidant capacity for kiwi slices, there is a positive correlation (R 2 = 0.7796). Microwave dried samples at 120 W particularly had the lowest TPC and antioxidant capacity. Freeze drying method yielded the closest values with respect to colour values, total phenol content and antioxidant capacity to those of fresh samples when compared to the other methods. 相似文献
44.
Opar Ekin Alpakut Gizem Parlatan Uğur Yavaş Seydi Yüksel Bahar Ünlü M. Burçin Buyru H. Faruk Baştu Ercan Ferhanoğlu Onur 《Instruments and Experimental Techniques》2022,65(3):444-451
Instruments and Experimental Techniques - With its elongated depth of focus, Bessel beams offer rapid and high aspect ratio ablation capability, in contrast to Gaussian beam counterparts. In this... 相似文献
45.
Onur Saray Gencaga Purcek Ibrahim Karaman Hans J. Maier 《Metallurgical and Materials Transactions A》2013,44(9):4194-4206
The stretch formability of ultrafine-grained (UFG) interstitial-free steel (IF-steel) produced by equal-channel angular extrusion/pressing (ECAE/P) via various strain paths was investigated with a miniaturized Erichsen test. A coarse-grained (CG) sample demonstrated high formability with an Erichsen index (EI) of 4.5 mm. Grain refinement by ECAE decreased the formability, but increased the required punch load (F EI) depending on the applied strain paths. The EI values were 0.35, 2.90, and 3.91 mm for 8A-, 8Bc-, and 8C-processed samples, respectively. Decrease in the biaxial stretch formability was attributed to the limited strain-hardening capacity of the UFG microstructure. Also, the grain morphology of the UFG microstructure was found to be very influential on stretch formability. Heavily elongated grain morphology in the 8A-processed microstructure resulted in the lowest formability due to the increased cracking tendency through elongated grain boundaries. However, the UFG microstructures with equiaxed grains obtained after 8C and 8Bc ECAE resulted in better formability compared to 8A. The UFG microstructure reduced the roughness (orange peel effect) of the free surface of the biaxial stretched samples by decreasing the non-uniform grain flow leading to the so-called orange peel effect. It should be noted that the strength and ductility values gained from uniaxial tensile tests are not comparable directly to the EI and F EI values determined from the Erichsen tests. Finally, it is important to emphasize that the UFG microstructure produced by a suitable strain path leading to equiaxed grains below 1 μm could be highly deformed even under multiaxial stress conditions. 相似文献
46.
In this paper, the performance of space time‐turbo trellis coded modulation (ST‐TTCM) is evaluated over Rician and Rayleigh fading channels with imperfect phase. We modify Baum–Welch (BW) algorithm to estimate the fading and phase jitter parameters for multi‐antenna configurations. Thus, we assume that the channel parameters change slower than carrier frequency. We know that, at high data rate transmissions over wireless fading channels, space–time block codes (STBC) provide the maximal possible diversity advantage. Here, the combined effects of the amplitude and the phase of the received signal are considered, each one modelled by Rician and Tikhonov distributions, respectively. We investigate space time‐turbo trellis coded modulation (ST‐TTCM) for 8‐PSK for several Rician factor K and phase distortion factor η. Thus, our results reflect the degradations both due to the effects of the fading on the amplitude and phase noise of the received signal while the channel parameters are estimated by BW algorithm. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
47.
Processing of context information is implicated in prefrontal functions as response selection or attention. N-methyl-D-aspartate (NMDA) receptors in the mammalian prefrontal cortex (PFC) and in the nidopallium caudolaterale (NCL) of birds, the avian functional equivalent of the PFC, are involved in learning, which also requires processing of context. The authors investigated the role of NMDA receptors in the pigeon (Columba livia) NCL for context processing and response selection in a simultaneous-matching-to-sample task with 2 trial types, requiring either processing of context information, delivered by a conditional stimulus (context dependent), or only recall of a stimulus-response association (fixed response). The competitive NMDA antagonist DL-2-amino-5-phosphonovaleric acid impaired performance only in context-dependent trials. Therefore, NMDA receptors in the avian PFC participate in response selection requiring context processing rather than in response selection per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
48.
Onur Şeker Bulent Akbas Jay Shen A. Zafer Ozturk 《The Structural Design of Tall and Special Buildings》2014,23(12):897-928
Steel moment‐resisting frames (SMRFs) are the most common type of structural systems used in steel structures. The first step of structural design for SMRFs starts with the selection of the structural sections on the basis of story drift limitation. ASCE 7 (2010) requires that the inelastic story drifts be obtained by multiplying the deflections determined by elastic analysis under design earthquake forces with a deflection amplification factor (Cd). For special moment‐resisting frames, Cd is given as 5.5 in ASCE 7 (2010). Lower Cd values will increase the overall inelastic response of the structure. On the other hand, the inelastic response of the structure is expected to be less severe when designed for higher Cd values. The performance objective is that the structure should sustain the inelastic deformation demand imposed due to design earthquake ground motions. This study aims at investigating the inelastic seismic response that low‐rise, medium‐rise and high‐rise SMRFs can experience under design earthquake ground motions and maximum considered earthquake (MCE) level ground motions and evaluating the deflection amplification factors (Cd) for SMRFs in a rational way. For this purpose, nonlinear dynamic time history and pushover analyses will be carried out on SMRFs with 4, 9 and 20 stories. The results indicate that the current practice for computing the inelastic story drifts for SMRFs is rational and the frames designed complying with the current code requirements can sustain the inelastic deformations imposed during design earthquake ground motions when seismically designed and detailed. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
49.
Tamer Sinmazçelik Egemen Avcu Mustafa Özgür Bora Onur Çoban 《Materials & Design》2011,32(7):3671-3685
During the past decades, increasing demand in aircraft industry for high-performance, lightweight structures have stimulated a strong trend towards the development of refined models for fibre-metal laminates (FMLs). Fibre metal laminates are hybrid composite materials built up from interlacing layers of thin metals and fibre reinforced adhesives. The most commercially available fibre metal laminates (FMLs) are ARALL (Aramid Reinforced Aluminium Laminate), based on aramid fibres, GLARE (Glass Reinforced Aluminium Laminate), based on high strength glass fibres and CARALL (Carbon Reinforced Aluminium Laminate), based on carbon fibres. Taking advantage of the hybrid nature from their two key constituents: metals (mostly aluminium) and fibre-reinforced laminate, these composites offer several advantages such as better damage tolerance to fatigue crack growth and impact damage especially for aircraft applications. Metallic layers and fibre reinforced laminate can be bonded by classical techniques, i.e. mechanically and adhesively. Adhesively bonded fibre metal laminates have been shown to be far more fatigue resistant than equivalent mechanically bonded structures. 相似文献
50.
Onur Alparslan Shin’ichi Arakawa Masayuki Murata 《Photonic Network Communications》2011,22(2):172-179
One of the difficulties with optical packet switched (OPS) networks is buffering optical packets in the network. The only
available solution that can currently be used for buffering in the optical domain is using long fiber lines called fiber delay
lines (FDLs), which have severe limitations. Moreover, the research on optical RAM presently being done is not expected to
achieve a large capacity soon. However, the burstiness of Internet traffic causes high packet drop rates and low utilization
in very small buffered OPS networks. We therefore propose a new node-based pacing algorithm for decreasing burstiness. We
show that by applying some simple pacing at the edge or core backbone nodes, the performance of very small optical RAM buffered
core OPS networks with variable-length packets can be notably increased. 相似文献