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31.
Effects of annealing process parameters such as annealing temperature, time, and atmosphere on the electrical resistivity
and transmittance properties of Ga-doped ZnO (ZnO:Ga) thin films deposited on glass by rf magnetron sputtering were investigated.
The electrical resistivity of a ZnO:Ga thin film is effectively decreased with increasing annealing temperature and time in
a reducing atmosphere such as N2 + 5%H2. This is attributed to passivation of grain boundaries and zinc ions by hydrogen atoms resulting in increases in carrier
concentration and mobility. Also the resistivity of 4.9 × 10−4Ω cm was obtained by annealing at 200°C for 15 h in the same atmosphere, which is not bad for a transparent conductor for
solar cell applications. However, annealing at a temperature higher than 400°C is less effective. The lowest resistivity of
2.3 × 10−4Ω cm was obtained by annealing at 400°C for 1 h in an N2 + 5%H2 atmosphere. The optical transmittance of the ZnO:Ga film is improved by annealing regardless of the annealing atmosphere.
Annealing in N2 + 5%H2 atmosphere widens the optical band gap, while annealing in an O2 atmosphere makes the band gap narrower, which can be explained as a blue shift phenomenon. 相似文献
32.
In this study, the pervaporative dehydration of diethylene glycol (DEG) through a commercial hollow fiber membrane was investigated at various feed temperatures in the range of 333–363 K with feeds containing 0.5–2.0 wt % water. Unlike the usual pervaporative dehydration process in which water is less volatile than the organic solvent, the feed mixture used in this study contained the organic component DEG, which is less volatile than water, resulting in unique permeation behaviors. The permeation behaviors of the individual components were investigated as functions of the feed temperature and feed composition. In particular, the effect of the low vapor pressure characteristics of DEG was investigated. Semi‐empirical equations for predicting the individual component fluxes and separation factor were quantified directly from actual dehydration pervaporation of DEG. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
33.
Woonghwan Ryu Myung-Jin Yim Seungyoung Ahn Junho Lee Woopoung Kim Kyung-Wook Paik Joungho Kim 《Components and Packaging Technologies, IEEE Transactions on》2000,23(3):542-545
This paper firstly reports on the high-frequency SPICE model of the ACF flip-chip interconnections up to 13 GHz. The extraction process is based on an optimization procedure, called a genetic algorithm, which is known as a robust optimization tool. The proposed equivalent circuit model of the ACF interconnection can readily be used in SPICE circuit simulations for signal integrity analysis of high-frequency packages. Two different ACF interconnections were studied using the Au-coated polymer ball and Ni-filled ball. The extracted models of the two ACFs were found strongly dependent on not only size and rigidity of the conducting balls, but also on their magnetic permeability 相似文献
34.
Jun-Hyuk Yim Youn Geun Jung Jong Sung Lim 《Korean Journal of Chemical Engineering》2010,27(1):284-288
High-pressure vapor-liquid equilibrium data were measured for the binary mixtures of CO2+n-propanol at various isotherms (313.15–343.15 K). The vapor and liquid compositions and pressures were measured in a circulation-type
apparatus. To facilitate easy equilibration, both vapor and liquid phases were circulated separately in the experimental apparatus
and the equilibrium composition was analyzed by an on-line gas chromatograph. The experimental data were compared with literature
results and correlated with the Peng-Robinson (PR) equations of state using the Wong-Sandler mixing rules. Calculated results
with PR EOS showed good agreement with our experimental data. 相似文献
35.
Hong Jae Yim Jae Hong Kim Sun-Jong Park Hyo-Gyoung Kwak 《Cement and Concrete Research》2012,42(11):1438-1446
Thermal damage in concrete usually induces contact-type defects, which result in degradation of the concrete's performance. This paper attempts to visualize the thermal damage in a multiscale, and characterizes the thermally damaged concrete using a nonlinear ultrasonic method. An impact-modulation method is used to obtain nonlinearity parameters, as a quantitative measure of contact-type defects, and shows better sensitivity than phase velocity variation as a linear ultrasonic method for thermally damaged concrete. The measured nonlinearity parameter is compared with the permeable pores, which reflect the occurrence of opening and pores in thermally damaged concrete. Degradation of concrete strength due to thermal damage is also assessed via the measurement. 相似文献
36.
Materials issues in nuclear-waste management 总被引:1,自引:0,他引:1
Man-Sung Yim K. Linga Murty 《JOM Journal of the Minerals, Metals and Materials Society》2000,52(9):26-29
In this article, materials issues in the management of nuclear waste, including its generation, processing, storage, transport,
and disposal, are examined for low-level and high-level waste, with an emphasis on the aspects of their immobilization and
long-term isolation. Selecting materials for low-level and high-level waste form and containers is reviewed, and the long-term
performance issues with these materials as barriers to nuclide migration or release are discussed.
Editor’s Note: A hypertext-enhanced version of this article is available on the web at www.tms.org/pubs/journals/JOM/0009/Yim-0009.html.
For more information, contact M.-S. Yim, North Carolina State University, Department of Nuclear Engineering, Raleigh, North
Carolina 27695-7909; (919) 515-1466; fax (919) 515-5115; e-mail yim@ncsu.edu. 相似文献
37.
38.
39.
Yip CT Huang H Zhou L Xie K Wang Y Feng T Li J Tam WY 《Advanced materials (Deerfield Beach, Fla.)》2011,23(47):5624-5628
A TiO(2) nanotube layer with a periodic structure is used as a photonic crystal to greatly enhance light harvesting in TiO(2) nanotube-based dye-sensitized solar cells. Such a tube-on-tube structure fabricated by a single-step approach facilitates good physical contact, easy electrolyte infiltration, and efficient charge transport. An increase of over 50% in power conversion efficiency is obtained in comparison to reference cells without a photonic crystal layer (under similar total thickness and dye loading). 相似文献
40.
Ju-Hyuk Yim Kyooho Jung Hyo-Jung Kim Hyung-Ho Park Chan Park Jin-Sang Kim 《Journal of Electronic Materials》2011,40(5):1010-1014
The solidification of alloys in the Bi2Te3-PbTe pseudobinary system at off- and near-eutectic compositions was investigated for their microstructure and thermoelectric
properties. Dendritic and lamellar structures were clearly observed due to the phase separation and the existence of a metastable
ternary phase. In this system, three phases with different compositions were observed: binary Bi2Te3, PbTe, and metastable PbBi2Te4. The Seebeck coefficient, electrical resistivity, and thermal conductivity of ternary alloys as well as binary compounds
were measured. The phonon thermal conductivities of Pb-Bi-Te alloys were lower than those in binary PbTe and Bi2Te3, which could have resulted from the increased interfacial area between phases due to the existence of the metastable ternary
phase and the resultant phase separation. 相似文献