全文获取类型
收费全文 | 889篇 |
免费 | 20篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 37篇 |
综合类 | 1篇 |
化学工业 | 172篇 |
金属工艺 | 45篇 |
机械仪表 | 20篇 |
建筑科学 | 8篇 |
能源动力 | 26篇 |
轻工业 | 63篇 |
水利工程 | 2篇 |
无线电 | 120篇 |
一般工业技术 | 169篇 |
冶金工业 | 169篇 |
原子能技术 | 23篇 |
自动化技术 | 60篇 |
出版年
2023年 | 9篇 |
2022年 | 20篇 |
2021年 | 29篇 |
2020年 | 14篇 |
2019年 | 4篇 |
2018年 | 14篇 |
2017年 | 11篇 |
2016年 | 17篇 |
2015年 | 5篇 |
2014年 | 29篇 |
2013年 | 46篇 |
2012年 | 28篇 |
2011年 | 38篇 |
2010年 | 38篇 |
2009年 | 31篇 |
2008年 | 42篇 |
2007年 | 30篇 |
2006年 | 33篇 |
2005年 | 28篇 |
2004年 | 16篇 |
2003年 | 21篇 |
2002年 | 13篇 |
2001年 | 19篇 |
2000年 | 5篇 |
1999年 | 33篇 |
1998年 | 64篇 |
1997年 | 40篇 |
1996年 | 33篇 |
1995年 | 28篇 |
1994年 | 20篇 |
1993年 | 22篇 |
1992年 | 10篇 |
1991年 | 7篇 |
1990年 | 9篇 |
1989年 | 8篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 11篇 |
1984年 | 5篇 |
1983年 | 4篇 |
1982年 | 4篇 |
1981年 | 5篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 9篇 |
1977年 | 14篇 |
1976年 | 12篇 |
1974年 | 3篇 |
1967年 | 2篇 |
1963年 | 2篇 |
排序方式: 共有915条查询结果,搜索用时 31 毫秒
1.
Tsuchiya Letícia Diniz Braga Lucas Fiorini de Faria Oliveira Otávio de Bettio Raphael Winckler Greghi Juliana Galvani Freire André Pimenta 《Personal and Ubiquitous Computing》2021,25(2):281-295
Personal and Ubiquitous Computing - This article presents a study concerning the evaluation of a smart home control system for elderly people with a sample of 10 users in a city in the interior of... 相似文献
2.
T Kuroda T Shimamoto T Mizushima T Tsuchiya 《Canadian Metallurgical Quarterly》1997,179(23):7600-7602
The activity of the NhaA Na+/H+ antiporter of Vibrio parahaemolyticus is inhibited by amiloride. We found an amino acid sequence in the NhaA that was identical to a putative amiloride binding domain of the Na+/H+ exchanger in mammalian cells. We constructed mutant NhaAs that had amino acid substitutions in the putative amiloride binding domain by site-directed mutagenesis. These include V62L (Val62 replaced by Leu), F63Y, F64Y, and L65F. Most mutant NhaAs showed decreased sensitivity for amiloride. Among these, the F64Y mutant NhaA showed the least amiloride sensitivity, with a Ki value 7 to 10 times greater than that in the wild type. Thus, the sequence between residues V62 and L65 in NhaA, especially F64, is very important for the inhibitory effect of amiloride on the antiporter. 相似文献
3.
Hot-carrier degradation of lightly doped drain (LDD) MOSFET's under ac stress is investigated. Enhanced ac degradation occurs in LDD MOSFET's as well as in single-drain MOSFET's. However, there is a peculiar degradation mechanism in LDD MOSFET's. For single-drain MOSFET's, enhanced ac degradation appears in both threshold voltage and transconductance at stress drain voltages larger than a critical value. On the other hand, for LDD MOSFET's, although the enhanced degradation in threshold voltage and transconductance appears at stress drain voltages larger than a critical value, the enhanced degradation in transconductance appears even under stress drain voltages lower than the critical value. The difference in the ac-enhanced degradation between LDD and single-drain structures can be explained by a hot hole generated neutral-electron-trap model and the change in hot-hole-injected oxide region according to stress bias conditions 相似文献
4.
Y Hasegawa T Hasegawa K Fujii H Konii M Anzo T Aso S Koto M Takada Y Tsuchiya 《Canadian Metallurgical Quarterly》1997,82(1):156-158
A case of huge desmoid tumor successfully treated by hyperthermoradiotherapy is described. A 23-year-old man with familial adenomatous polyposis was operated upon for a desmoid tumor in the mesenterium involving the right kidney and small intestine in 1988. In 1990, the tumor recurred and could not be resected because of the involvement of the vena cava. The tumor grew larger and larger, and occupied two-thirds of the right lower quadrant. Several therapies using sulindac, tamoxifen, prednisolone, indomethacin, luteinizing hormone-releasing hormone analogue, and ascorbate were all ineffective. Finally, the combination of radiation and hyperthermia was used over a 6-month period. At the end of the hyperthermoradiotherapy, the tumor in the abdominal wall was markedly reduced in size, and the protruded abdominal wall became flat. To our best knowledge, this is the first report of the successful treatment of a huge desmoid tumor by hyperthermoradiotherapy. 相似文献
5.
The hot-carrier-injected oxide region in the front and back interfaces is systematically clarified for fully depleted surface-channel nMOSFET's and surface-channel and buried-channel pMOSFET's fabricated on an ultra-thin (50 nm)-film SIMOX wafer. Based on these results, the influence of these injected carriers on front-channel properties is investigated. NMOSFET degradation is shown to be caused by hot-carriers injected into the drain side of the front oxide and pMOSFET degradation by hot-electrons injected into the drain side of both the front oxide and the back oxide. Additionally, it is shown experimentally that these fully depleted devices with effective channel lengths between 0.1-0.2 μm have fairly high hot-carrier immunity, even for single-drain structures 相似文献
6.
Inoue Y. Kobayashi K. Tanaka E. Okamoto S. Tsuchiya Y. Takizawa K. 《Broadcasting, IEEE Transactions on》1996,42(3):259-265
In order to realize full-color electroluminescent (EL) displays, which are expected as a dominant candidate for the future multimedia flat panel display, blue EL devices with SrGa2S4:Ce have been prepared by molecular beam epitaxy (MBE). This paper proposes a novel deposition method employing Sr metal and Ga2S4 compound as the source materials. A single-phase SrGa2S4 layer is obtained in a Ga2S3/Sr flux ratio of 60 and at the growth temperature of 560°C. We have obtained the well-saturated blue with CIE color coordinates of x=0.14, y=0.14 and brighter blue EL devices made by optimizing the growth conditions in MBE. The maximum luminance of 70 cd/m2 in comparison with the 3 cd/m2 of our previous EL devices, is achieved at a driving frequency of 1 kHz 相似文献
7.
The electrical properties and internal friction in (40–x)Fe2O3·xNa20.60P2O5 glasses were measured. Two or three peak on internal friction were observed in the temperature range of –100 to 300° C at a frequency of about 1 Hz. The peak area of internal friction could be explained quantitatively by the additivity law of diffusion of Na+ ion and hopping of electrons which are carriers similar to those of dielectric loss. Activation energy, peak temperature of dielectric loss and internal friction showed almost the same value. Both relaxation phenomena have the same mechanism which is due to the diffusion of Na+ion and the hopping of electrons between Fe2+ Fe3+. The high-temperature peak is assumed to result from the interaction between protons or alkali ions and non-bridging oxygen. 相似文献
8.
Films of spinel-type ferrite, MFe2O4 (M=Ni, Co, Mg, Li0.5Fe0.5) have been prepared by a dip-coating method from the sol-gel process. Ferric nitrate, nickel nitrate, cobalt nitrate and lithium nitrate were used as raw materials, and glycerol and formamide were used as solvents. A film was prepared by dipping a silica glass plate. The spinel-type ferrite was obtained by heat-treatment at 700–900°C for 2 h in air. The film thickness was about 0.8 m. The saturation magnetization, r, of the film and powder with composition 50NiO·50Fe2O3 was 196 emu cm–3 and 29.1 emu g–1, respectively, and the coercive force,H
c, was 140 and 95 Oe, respectively, after heat-treatment at 800°C for 2 h. In particular, the films were shown to have a much largerH
c than the powder. The grain growth of spinel ferrite may be subject to restriction because it is in progress above an amorphous base-plate. The crystals are therefore aligned with the base-plate and have uniaxial anisotropy. 相似文献
9.
Sn-incorporated folded sheets mesoporous materials (Sn-FSM-16) with various contents of Sn were synthesized by using a mixture of water glass, SnCl4 and NaOH as starting materials. Hexadecyltrimethyl-ammonium chloride (surfactant) was used to intercalate into the layered silicate. The reaction process was followed by measurements of XRD patterns of intermediates. The Sn-FSM-16 was formed via the following mechanism: (1) layered silicates such as - - and -Na2Si2O5 were formed as intermediates by the calcination of the mixture of the starting materials; (2) the surfactant was intercalated into the layered silicates; (3) the surfactant-silicate complex with hexagonal structure was obtained as a precursor of Sn-FSM-16; (4) the precursor was calcined to decompose the surfactant in the interlayer and was changed to Sn-FSM-16. The structural aspect of Sn in Sn-FSM-16 was studied by XPS profiles of Sn 3d
5/2 and Si2p, 29 Si MAS NMR and FTIR. The content of Sn in Sn-FSM increased with increasing concentrations of both Sn and NaOH in the starting materials. The surface area of Sn-FSM-16 decreased with an increase of Sn content in Sn-FSM (1160–620 m2/g). 相似文献
10.
This study examines further the phenomena of the modification of coal carbonizations by organic additives. Anthracene, pyrene and chrysene modify the carbonization in a closed system of coking coals as observed from increases in the size of optical textures of resultant cokes. Weakly caking coals are unaffected. Chrysene is the most efficient modifier probably because of its lowest calculated free valence. The co-additives tetralin and hydrogenated anthracene oil further enhance the modification processes so obviating the necessity to use hydrogenated additives. Co-carbonizations of oxidized coking and caking coals with decacyclene are effective in removing the effects of mild oxidation. Increased rates of carbonization enhance the sizes of optical textures of resultant cokes. 相似文献