全文获取类型
收费全文 | 3512篇 |
免费 | 183篇 |
国内免费 | 14篇 |
专业分类
电工技术 | 66篇 |
综合类 | 3篇 |
化学工业 | 703篇 |
金属工艺 | 147篇 |
机械仪表 | 244篇 |
建筑科学 | 51篇 |
矿业工程 | 2篇 |
能源动力 | 151篇 |
轻工业 | 385篇 |
水利工程 | 39篇 |
石油天然气 | 4篇 |
无线电 | 577篇 |
一般工业技术 | 748篇 |
冶金工业 | 221篇 |
原子能技术 | 49篇 |
自动化技术 | 319篇 |
出版年
2024年 | 12篇 |
2023年 | 45篇 |
2022年 | 61篇 |
2021年 | 110篇 |
2020年 | 55篇 |
2019年 | 75篇 |
2018年 | 90篇 |
2017年 | 78篇 |
2016年 | 106篇 |
2015年 | 88篇 |
2014年 | 131篇 |
2013年 | 203篇 |
2012年 | 248篇 |
2011年 | 300篇 |
2010年 | 210篇 |
2009年 | 208篇 |
2008年 | 216篇 |
2007年 | 171篇 |
2006年 | 165篇 |
2005年 | 119篇 |
2004年 | 125篇 |
2003年 | 101篇 |
2002年 | 123篇 |
2001年 | 101篇 |
2000年 | 68篇 |
1999年 | 64篇 |
1998年 | 127篇 |
1997年 | 70篇 |
1996年 | 50篇 |
1995年 | 28篇 |
1994年 | 31篇 |
1993年 | 24篇 |
1992年 | 26篇 |
1991年 | 14篇 |
1990年 | 7篇 |
1989年 | 7篇 |
1988年 | 6篇 |
1987年 | 7篇 |
1986年 | 5篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 6篇 |
1982年 | 4篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1976年 | 2篇 |
1972年 | 1篇 |
1969年 | 2篇 |
1967年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有3709条查询结果,搜索用时 15 毫秒
71.
Jeonghun Kim Jong Kwan Koh Byeonggwan Kim Sung Hoon Ahn Hyungju Ahn Du Yeol Ryu Jong Hak Kim Eunkyoung Kim 《Advanced functional materials》2011,21(24):4633-4639
An iodine‐free solid‐state dye‐sensitized solar cell (ssDSSC) is reported here, with 6.8% energy conversion efficiency—one of the highest yet reported for N719 dye—as a result of enhanced light harvesting from the increased transmittance of an organized mesoporous TiO2 interfacial layer and the good hole conductivity of the solid‐state‐polymerized material. The organized mesoporous TiO2 (OM‐TiO2) interfacial layer is prepared on large‐area substrates by a sol‐gel process, and is confirmed by scanning electron microscopy (SEM) and grazing incidence small‐angle X‐ray scattering (GISAXS). A 550‐nm‐thick OM‐TiO2 film coated on fluorine‐doped tin oxide (FTO) glass is highly transparent, resulting in transmittance increases of 8 and 4% compared to those of the bare FTO and conventional compact TiO2 film on FTO, respectively. The high cell performance is achieved through careful control of the electrode/hole transport material (HTM) and nanocrystalline TiO2/conductive glass interfaces, which affect the interfacial resistance of the cell. Furthermore, the transparent OM‐TiO2 film, with its high porosity and good connectivity, exhibits improved cell performance due to increased transmittance in the visible light region, decreased interfacial resistance ( Ω ), and enhanced electron lifetime ( τ ). The cell performance also depends on the conductivity of HTMs, which indicates that both highly conductive HTM and the transparent OM‐TiO2 film interface are crucial for obtaining high‐energy conversion efficiencies in I2‐free ssDSSCs. 相似文献
72.
Anisotropic self-alignment of the noncircular pads is investigated to reduce the misalignment in electronic packaging, and
the effects of the direction and length ratio of the noncircular pads are analyzed. The restoring forces of circular and noncircular
pads are calculated numerically using the surface evolver and are compared with the experimental data. The restoring force
in the minor-axis direction of the noncircular pad becomes largest followed by the circular pad and the major-axis direction
of the noncircular pad. Directionality increases with the length ratio, which implies that more accurate alignment can be
achieved in the specific direction. 相似文献
73.
Seong-Min Choe Jeong-Ah Ahn Ohyun Kim 《Electron Device Letters, IEEE》2001,22(3):121-123
Germanium is ion-implanted deeply into the bottom of a Si film before excimer laser annealing begins. During the solidification step, the implanted Ges form a high thermal resistive Si1-xGex alloy, which reduces the thermal extraction rate of laser energy and the grain growth rate. Laterally larger but double-stacked grains were achieved with a higher Ge implant dose and a slower grain growth. The performance of fabricated poly-TFTs has been enhanced with a Ge 5×1015/cm2 at 80 keV implant but deteriorated at a higher dose. We attribute this enhancement to a laterally enlarged grain and show that the performance of TFT is deteriorated more dominantly by other Ge-related factors than by surface roughening and Ge-induced defect creation 相似文献
74.
Min B.G. Kim H.C. Choi J.W. Ryu G.H. Seo K.P. Rho J.R. Ahn H. Kim S.W. Diegel P.D. Olsen D.B. 《IEEE transactions on bio-medical engineering》1990,37(12):1195-1200
A new type of electromechanical total artificial heart (TAH) based on circular rolling-cylinder mechanism was developed to overcome critical problems in motor-driven artificial hearts such as large size and difficulties in fitting the heart to atrial remnants and arterial vessels. Its performance and reliability were evaluated in mock circulation and in an animal implant experiment. The total weight and volume of the pump is 650 g and 600 mL, respectively. This new pump was implanted in a calf for total heart replacement and 96 h of survival was achieved. The whole system, including pump, controller, and control algorithm performed well enough to improve the prospect of eventual clinical application of our TAH system. 相似文献
75.
Disposable smart lab on a chip for point-of-care clinical diagnostics 总被引:13,自引:0,他引:13
Ahn C.H. Jin-Woo Choi Beaucage G. Nevin J.H. Jeong-Bong Lee Puntambekar A. Lee J.Y. 《Proceedings of the IEEE. Institute of Electrical and Electronics Engineers》2004,92(1):154-173
This paper presents the development of a disposable plastic biochip incorporating smart passive microfluidics with embedded on-chip power sources and integrated biosensor array for applications in clinical diagnostics and point-of-care testing. The fully integrated disposable biochip is capable of precise volume control with smart microfluidic manipulation without costly on-chip microfluidic components. The biochip has a unique power source using on-chip pressurized air reservoirs, for microfluidic manipulation, avoiding the need for complex microfluidic pumps. In addition, the disposable plastic biochip has successfully been tested for the measurements of partial oxygen concentration, glucose, and lactate level in human blood using an integrated biosensor array. This paper presents details of the smart passive microfluidic system, the on-chip power source, and the biosensor array together with a detailed discussion of the plastic micromachining techniques used for chip fabrication. A handheld analyzer capable of multiparameter detection of clinically relevant parameters has also been developed to detect the signals from the cartridge type disposable biochip. The handheld analyzer developed in this work is currently the smallest analyzer capable of multiparameter detection for point-of-care testing. 相似文献
76.
Parallel manipulator is a closed-kinematic chain mechanism in which performance of its end effector – moving platform is contributed by its independent actuators. In traditional designs, each elemental actuator has its own controller as well as reference input, and it works independently without gathering information from its neighbors. Consequently, as one of the actuators cannot keep up with the others, the platform performance is easily deteriorated due to the lack of coherence between these actuators. Therefore, the aim of this paper is to design a 3-R planar parallel robot and develop a proper synchronization controller for its tracking control task. Adaptive Network Based Fuzzy Inference System (ANFIS) algorithm was modified and applied as the main strategy of this synchronization controller. The controller is then able to compensate errors between the actuators and enforce them to cooperate harmonically with each other regardless external disturbances caused by the outside environment or geometrical constraints of the closed-loop structure. Simulations and practical experiments on a scaled parallel robot were carried out to evaluate the designed controller. The results showed that by applying the proposed control technique, the working errors of the component actuators converged quickly to zero almost at the same time. As a result, the tracking performance of the common platform was significantly improved in comparison with the performance when applying a non-synchronization controller. The proposed method is effective in controlling systems which require collaborations between the sub-agents. 相似文献
77.
Mousumi Garai Manmatha Mahato Sanghee Nam Eunji Kim Darae Seo Yonghee Lee Van Hiep Nguyen Saewoong Oh Pradeep Sambyal Hyunjoon Yoo Ashhad Kamal Taseer Sheraz Ali Syed Hee Han Chi Won Ahn Jaehwan Kim Il-Kwon Oh 《Advanced functional materials》2023,33(10):2212252
Electro-ionic soft actuators, capable of continuous deformations replacing non-compliant rigid mechanical components, attract increasing interest in the field of next-generation metaverse interfaces and soft robotics. Here, a novel MXene (Ti3C2Tx) electrode anchoring manganese-based 1,3,5-benzenetricarboxylate metal-organic framework (MnBTC) for ultrastable electro-ionic artificial muscles is reported. By a facile supramolecular self-assembly, the Ti3C2Tx-MnBTC hybrid nanoarchitecture forms coordinate bond, hydrogen bond, and hydrophilic interaction with the conducting polymer of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), resulting in a mechanically flexible and electro-ionically active electrode. The superior electrical and electrochemical performances of the electrode stem from the synergistic effects between intrinsically hierarchical nanoarchitecture of MnBTC and rapid electron transport behavior of Mxene, leading to fast diffusion and accommodation of ions in the ion-exchangeable membrane. The developed artificial muscle based on Ti3C2Tx-MnBTC is found to exhibit high bending displacement (12.5 mm) and ultrafast response time (0.77 s) under a low driving voltage (0.5 V), along with wide frequency response (0.1–10 Hz) and exceptional stability (98% retention at 43,200 s) without any distortion of actuation performance. Furthermore, the designed electro-active artificial muscle is successfully used to demonstrate mimicry of eye motions including eyelid blinking and eyeball movement in a doll. 相似文献
78.
Hyunjung Jin Kyuyeon Kim Sungmin Park JinHyeong Rhee Hyungju Ahn Dong Jun Kim Kyeongmin Kim Jun Hong Noh Taek-Soo Kim Eul-Yong Shin Hae Jung Son 《Advanced functional materials》2023,33(47):2304930
Recyclable conjugated polymers are important for realizing eco-friendly electronics with advantages of solution processability and flexibility. A recyclable conjugated polymer, PY-TIP is developed, of which a key monomer is successfully extracted via a mild depolymerization process and is reused for the synthesis of novel conjugated polymers. One-shot preparation of polymer acceptor and its bulk-heterojunction (BHJ) is demonstrated from the recycled monomer, Y5-TA, for the first time and the resulting BHJ film shows optimal nanoscale morphology for efficient charge generation and transport. As a result, the solar cells prepared using the BHJ film show a higher efficiency of 13.08% and much improved thermal and mechanical stability compared with those based on the small molecular acceptor. These results are important in that the various polymers can be prepared from the recycled monomer in a solid state without organic solvents and purification step and this strategy is effective for improving the thermal and mechanical stability of the BHJ film as well as achieving high photovoltaic performance. PY-TIP is exemplary in that it can reproduce its monomer which can be used to synthesize conjugated polymers with novel chemical structures and physical properties. This work provides a design guideline for developing recyclable conjugated polymers with dynamic covalent bonds. 相似文献
79.
At present, the major drawback for mobile phones is the issue of power consumption. As one of the alternatives to decrease the power consumption of standard, power-hungry location-based services usually require the knowledge of how individual phone features consume power. A typical phone feature is that the applications related to multimedia streaming utilize more power while receiving, processing, and displaying the multimedia contents, thus contributing to the increased power consumption. There is a growing concern that current battery modules have limited capability in fulfilling the long-term energy need for the progress on the mobile phone because of increasing power consumption during multimedia streaming processes. Considering this, in this paper, we provide an offline meaning sleep-mode method to compute the minimum power consumption comparing with the power-on solution to save power by implementing energy rate adaptation (RA) mechanism based on mobile excess energy level purpose to save battery power use. Our simulation results show that our RA method preserves efficient power while achieving better throughput compared with the mechanism without rate adaptation (WRA). 相似文献
80.
Wireless data communication (WDC) services are increasingly penetrating the market. The two main alternative WDC technologies are wireless LAN and mobile Internet. Services based on these technologies display differences in quality attributes such as terminal device, data transmission speed, pricing scheme and so on. How consumers choose between these two alternatives will be determined by their preferences regarding such quality attributes. In turn, their preferences will affect the evolution of WDC services and related technologies. This study employs a conjoint analysis of consumer valuations of quality attributes of wireless LAN and mobile Internet services. Respondents rate hypothetical service alternatives featuring various combinations of quality attributes. By estimating consumer willingness to pay for the attributes of WDC services, the authors predict the evolution of WDC services and related technologies along various quality dimensions, make a comparison with the results of a previous study, and draw policy implications for national‐and company‐level R&D strategies. 相似文献