全文获取类型
收费全文 | 3620篇 |
免费 | 184篇 |
国内免费 | 4篇 |
专业分类
电工技术 | 25篇 |
综合类 | 4篇 |
化学工业 | 863篇 |
金属工艺 | 321篇 |
机械仪表 | 89篇 |
建筑科学 | 106篇 |
矿业工程 | 18篇 |
能源动力 | 96篇 |
轻工业 | 506篇 |
水利工程 | 24篇 |
石油天然气 | 12篇 |
无线电 | 203篇 |
一般工业技术 | 492篇 |
冶金工业 | 203篇 |
原子能技术 | 25篇 |
自动化技术 | 821篇 |
出版年
2024年 | 8篇 |
2023年 | 44篇 |
2022年 | 104篇 |
2021年 | 142篇 |
2020年 | 86篇 |
2019年 | 103篇 |
2018年 | 180篇 |
2017年 | 164篇 |
2016年 | 203篇 |
2015年 | 165篇 |
2014年 | 162篇 |
2013年 | 252篇 |
2012年 | 220篇 |
2011年 | 776篇 |
2010年 | 171篇 |
2009年 | 158篇 |
2008年 | 140篇 |
2007年 | 121篇 |
2006年 | 76篇 |
2005年 | 63篇 |
2004年 | 73篇 |
2003年 | 46篇 |
2002年 | 56篇 |
2001年 | 32篇 |
2000年 | 26篇 |
1999年 | 20篇 |
1998年 | 28篇 |
1997年 | 27篇 |
1996年 | 16篇 |
1995年 | 23篇 |
1994年 | 16篇 |
1993年 | 11篇 |
1992年 | 9篇 |
1991年 | 9篇 |
1990年 | 10篇 |
1989年 | 11篇 |
1988年 | 9篇 |
1987年 | 8篇 |
1986年 | 7篇 |
1985年 | 8篇 |
1984年 | 4篇 |
1983年 | 3篇 |
1982年 | 3篇 |
1981年 | 4篇 |
1979年 | 2篇 |
1976年 | 2篇 |
1975年 | 1篇 |
1972年 | 1篇 |
1971年 | 1篇 |
1969年 | 1篇 |
排序方式: 共有3808条查询结果,搜索用时 0 毫秒
41.
Yifei Li Akshay Singh Kate Reidy Seong Soon Jo Frances M. Ross Rafael Jaramillo 《Advanced functional materials》2020,30(36)
The synthesis of large‐area TiS2 thin films is reported at temperatures as low as 500 °C using a scalable two‐step method of metal film deposition followed by sulfurization in an H2S gas furnace. It is demonstrated that the lowest‐achievable sulfurization temperature depends strongly on the oxygen background during sulfurization. This dependence arises because Ti? O bonds present a substantial kinetic and thermodynamic barrier to TiS2 formation. Lowering the sulfurization temperature is important to make smooth films, and to enable integration of TiS2 and related transition metal dichalcogenides—including metastable phases and alloys—into device technology. 相似文献
42.
Thin-film transistors (TFTs) fabricated in polysilicon films deposited by plasma enhanced chemical vapor deposition (PECVD)
were characterized. The transistors were fabricated using a low temperature process (i.e., <- 700° C). The characteristics of the devices were found to improve as the deposition temperature of the polysilicon film
increased. The best characteristics (μ
FE of 15 cm2/V
s andV
TH of 2.2V) were measured in the devices fabricated in the film deposited at 700° C. The devices fabricated in the PECVD polysilicon
films were compared to those fabricated in polysilicon films deposited by thermal CVD in the same reactor in order to decouple
the effect of the plasma. A coplanar electrode structure TFT with adequate characteristics (μ
FE of 8 cm2/V
s) was also demonstrated in the PECVD polysilicon films. 相似文献
43.
Selective deposition of TiSi2 on oxide patterned wafers using low pressure chemical vapor deposition
The selective deposition of titanium disilicide was investigated using a cold-wall, low pressure chemical vapor deposition
(LPCVD) technique with silane and titanium tetrachloride as the silicon and titanium sources, respectively. In-situ hydrogen
plasma effectively cleaned the silicon wafer surface for deposition of C54 TiSi2 at 760‡ C with full selectivity. A new method using a plasma only at the beginning of the deposition of the silicide further
decreased the temperature to 680‡ C without losing selectivity. The result was a fine grained film probably due to the enhanced
nucleation rate of the silicide. Cross-sectional TEM studies showed that the silicide grew into the silicon substrate, suggesting
significant silicon consumption. The silicon substrate, consequently, seems to play a major role in the silicide formation.
Silane, on the other hand, plays a minor role as a silicon source but does act as a scavenger of HC1 in the gas or on the
silicide surface. 相似文献
44.
Pedro J. Castro Joaquim J. Barroso Rafael A. Corrêa 《Journal of Infrared, Millimeter and Terahertz Waves》2000,21(4):633-645
A study of the electrodynamical properties of a Ka-band gyrotron open resonator was experimentally conducted. Experiments were accomplished to measure resonant frequencies and their respective loaded quality factors for TE modes in the frequency range from 26 to 40 GHz. In particular, a perturbation technique was used to determine the axial, radial and azimuthal electric field profiles, as an identification method of the TE021 mode operating around 35 GHz. In any experimental event, good agreement with the values predicted by theory was found. 相似文献
45.
Rafael A. Arce-Nazario Manuel Jiménez Domingo Rodríguez 《Journal of Signal Processing Systems》2008,53(3):367-382
We present an algorithmically-aware, high-level partitioning methodology for discrete cosine transforms (DCT) targeted to
distributed hardware architectures. The methodology relies on the exploration of alternate DCT formulations as part of the
partition optimization process. To the best of our knowledge, no previously proposed DCT algorithm exists that is capable
of consistently producing alternate regular formulations for an n-size DCT. Hence, a new Cooley-Tukey-like DCT factorization algorithm was developed to allow exploration of alternate formulations
as part of the partitioning optimization process. The use of our factorization mechanism along with a greedy strategy to explore
the space of equivalent DCT formulations yielded partitioning solutions with as much as 18% reduction in latency and 83% reduction
in run-time as compared to previously proposed regular DCT formulations.
相似文献
Domingo RodríguezEmail: |
46.
Michael K. Hausmann Gilberto Siqueira Rafael Libanori Dimitri Kokkinis Antonia Neels Tanja Zimmermann Andr R. Studart 《Advanced functional materials》2020,30(4)
Cellulose is an attractive material resource for the fabrication of sustainable functional products, but its processing into structures with complex architecture and high cellulose content remains challenging. Such limitation has prevented cellulose‐based synthetic materials from reaching the level of structural control and mechanical properties observed in their biological counterparts, such as wood and plant tissues. To address this issue, a simple approach is reported to manufacture complex‐shaped cellulose‐based composites, in which the shaping capabilities of 3D printing technologies are combined with a wet densification process that increases the concentration of cellulose in the final printed material. Densification is achieved by exchanging the liquid of the wet printed material with a poor solvent mixture that induces attractive interactions between cellulose particles. The effect of the solvent mixture on the final cellulose concentration is rationalized using solubility parameters that quantify the attractive interparticle interactions. Using X‐ray diffraction analysis and mechanical tests, 3D printed composites obtained through this process are shown to exhibit highly aligned microstructures and mechanical properties significantly higher than those obtained by earlier additively manufactured cellulose‐based materials. These features enable the fabrication of cellulose‐rich synthetic structures that more closely resemble the exquisite designs found in biological materials grown by plants in nature. 相似文献
47.
Rafael Pass Wei-Lung Dustin Tseng Muthuramakrishnan Venkitasubramaniam 《Journal of Cryptology》2014,27(1):45-66
We provide a more general and, in our eyes, simpler variant of Prabhakaran, Rosen and Sahai’s (FOCS ’02, pp. 366–375, 2002) analysis of the concurrent zero-knowledge simulation technique of Kilian and Petrank (STOC ’01, pp. 560–569, 2001). 相似文献
48.
Dux-Santoy L Sebastian R Felix-Rodriguez J Ferrero JM Saiz J 《IEEE transactions on bio-medical engineering》2011,58(12):3475-3478
The use of antiarrhythmic drugs is common to treat heart rhythm disorders. Computational modeling and simulation are promising tools that could be used to investigate the effects of specific drugs on cardiac electrophysiology. In this paper, we study the multiscale effects of dofetilide, a drug that blocks IKr, from cellular to organ level paying special attention to its effect on heart structures, in particular the specialized cardiac conduction system (CCS). We include a model of the CCS in a patient-specific anatomical ventricular model and study the drug effects in simulations with and without a CCS. Results confirmed the expected effects of dofetilide at cellular level, increasing the action potential duration, and at organ level, prolonging the QT segment. Notable differences are shown between models with and without the CCS on action potential duration distributions. These techniques show the importance of heart heterogeneity and the global effects of the interaction of drugs with cardiac structures. 相似文献
49.
Sean J. Barbeau Miguel A. Labrador Philip L. Winters Rafael Perez Nevine Labib Georggi 《Communications Magazine, IEEE》2006,44(11):156-163
The widespread use of cellular telephones and the availability of user-location information are facilitating the development of new personalized, location-based applications. However, as of today, most of these applications are unidirectional and text-based where the user subscribes and the system sends a text message when appropriate. This article describes a modular and general architecture that supports the development of interactive, multimedia, location-based applications, providing an extra level of service to the users. The flexibility of the architecture is demonstrated by presenting the wireless safety security system (Wi-Via) and other potential applications 相似文献
50.
Christina Gretener Julian Perrenoud Lukas Kranz Luisa Kneer Rafael Schmitt Stephan Buecheler Ayodhya N. Tiwari 《Progress in Photovoltaics: Research and Applications》2013,21(8):1580-1586
The ability to grow efficient CdTe/CdS solar cells in substrate configuration would not only allow for the use of non‐transparent and flexible substrates but also enable a better control of junction formation. Yet, the problems of barrier formation at the back contact as well as the formation of a p–n junction with reduced recombination losses have to be solved. In this work, CdTe/CdS solar cells in substrate configuration were developed, and the results on different combinations of back contact materials are presented. The Cu content in the electrical back contact was found to be a crucial parameter for the optimal CdCl2‐treatment procedure. For Cu‐free cells, two activation treatments were applied, whereas Cu‐containing cells were only treated once after the CdTe deposition. A recrystallization behavior of the CdTe layer upon its activation similar to superstrate configuration was found; however, no CdTe–CdS intermixing could be observed when the layers were treated consecutively. Remarkably high VOC and fill factor of 768 mV and 68.6%, respectively, were achieved using a combination of MoO3, Te, and Cu as back contact buffer layer resulting in 11.3% conversion efficiency. With a Cu‐free MoO3/Te buffer material, a VOC of 733 mV, a fill factor of 62.3%, and an efficiency of 10.0% were obtained. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献