全文获取类型
收费全文 | 3835篇 |
免费 | 195篇 |
国内免费 | 6篇 |
专业分类
电工技术 | 73篇 |
综合类 | 2篇 |
化学工业 | 872篇 |
金属工艺 | 128篇 |
机械仪表 | 229篇 |
建筑科学 | 94篇 |
矿业工程 | 1篇 |
能源动力 | 143篇 |
轻工业 | 336篇 |
水利工程 | 13篇 |
石油天然气 | 1篇 |
无线电 | 688篇 |
一般工业技术 | 776篇 |
冶金工业 | 240篇 |
原子能技术 | 43篇 |
自动化技术 | 397篇 |
出版年
2023年 | 42篇 |
2022年 | 57篇 |
2021年 | 83篇 |
2020年 | 73篇 |
2019年 | 78篇 |
2018年 | 109篇 |
2017年 | 116篇 |
2016年 | 128篇 |
2015年 | 107篇 |
2014年 | 160篇 |
2013年 | 259篇 |
2012年 | 233篇 |
2011年 | 306篇 |
2010年 | 210篇 |
2009年 | 228篇 |
2008年 | 211篇 |
2007年 | 171篇 |
2006年 | 184篇 |
2005年 | 143篇 |
2004年 | 146篇 |
2003年 | 120篇 |
2002年 | 103篇 |
2001年 | 96篇 |
2000年 | 81篇 |
1999年 | 56篇 |
1998年 | 124篇 |
1997年 | 76篇 |
1996年 | 63篇 |
1995年 | 41篇 |
1994年 | 36篇 |
1993年 | 22篇 |
1992年 | 20篇 |
1991年 | 23篇 |
1990年 | 16篇 |
1989年 | 13篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 8篇 |
1985年 | 14篇 |
1984年 | 9篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 6篇 |
1978年 | 3篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1973年 | 5篇 |
1972年 | 2篇 |
1969年 | 2篇 |
排序方式: 共有4036条查询结果,搜索用时 15 毫秒
181.
Min-Bae?Kim Jong-Ho?Moon Chang-Ha?LeeEmail author Hyungwoong?Ahn Wonihl?Cho 《Korean Journal of Chemical Engineering》2004,21(3):703-711
The effect of radial heat transfer on temperature swing adsorption (TSA) was studied by using an air-drying TSA experiment.
The experimental dynamics of water adsorption and thermal regeneration in a fixed bed packed with zeolite 13X were used to
evaluate the predicted results from the developed models. One-and two-dimensional models for energy balance with various equations
describing internal velocity were compared in terms of the prediction of transient dynamics of TSA. Since the heat effect
in adsorption step depended on the isosteric heat of adsorption, a dynamic simulation was performed under adiabatic, near-adiabatic,
and constant wall temperature conditions. A comparison between one-and two-dimensional models was also made under near-adiabatic
condition, which reflected on the experimental condition. There was little difference between adsorption breakthrough curves
predicted by the one- and two-dimensional models because the radial distribution of temperature was negligible at the adsorption
step. In the case of the regeneration step, a small difference between two models was expected just at the early period of
time because the radial effect disappeared with time. One-dimensional model could provide an adequate prediction of the transient
dynamics in this system when the wall energy balance was included. 相似文献
182.
Myung-Yeon Cho Sung-Joon Park So-Mang Kim Dong-Won Lee Hong-Ki Kim Sang-Mo Koo Kyoung-Sook Moon Jong-Min Oh 《Ceramics International》2018,44(14):16548-16555
Alumina and polytetrafluoroethylene (Al2O3-PTFE) composite films were fabricated by a simple aerosol deposition (AD) process, to confirm its applicability for various display screens requiring water resistant, anti-smudge and easy-to-clean properties. The surface morphologies, hydrophobic properties, and transparencies of the composite films with different PTFE contents, varying from 0.01 to 1?wt% were investigated. As a result, the composite films with over 0.3?wt% PTFE showed a sudden rise in surface roughness and low transmittance, despite having the highest contact angle of 128° at a PTFE content of 0.3?wt%. From the energy dispersive spectrometer analysis, the crash-cushioning effect of PTFE and agglomerated PTFE particles were determined to be major causes of surface roughness and opacity. In contrast, the transmittance showed a tendency to be enhanced, with an increasing PTFE content in the range of 0.01, 0.05, and 0.1?wt% PTFE, respectively. Especially, the film with 0.1?wt% of PTFE had contact angle of 111° and exhibited a high transmittance of over 75%, which was inferred to be an appropriate amount of PTFE, with a high elongation filling up the surface and the internal defects, leading to an enhancement of transparency. Consequently, these results implied that the AD-prepared Al2O3-PTFE composite coatings are promising candidates for various display applications. 相似文献
183.
Wu Bin Ying Da Som Moon Min Woo Lee Na Yeong Ko Nho Hoon Kwak Bumjae Lee Jin Zhu Ruoyu Zhang 《应用聚合物科学杂志》2018,135(5)
To simultaneously improve the fracture toughness and heat resistance of a cured toughened epoxy resin along with a reduction in its viscosity during the mixing process, two novel polysulfone‐type polymers are synthesized via azide–alkyne polymerization for use as toughening agents. The epoxy resin toughened with these polymers by in situ azide–alkyne polymerization during the cure process, which shows excellent processibility and based on the significantly lower viscosity (61 and 62 cP) during epoxy mixing process than that of commonly commercial polyethersulfone (PES, 127,612 cP). The novel polysulfone‐type polymer toughened epoxy resin showed the advantage in excellent fracture toughness than the PES toughened epoxy. In addition, the glass transition temperature of the novel polysulfone‐type polymer toughened epoxy resin is similar to that of the neat one (~230 °C) and does not decrease, which implies excellent heat resistance of the toughened epoxy. These phenomena can be attributed to the formation of semi‐interpenetrating polymer networks comprising the epoxy network and the linear polysulfone‐type polymers. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45790. 相似文献
184.
Moon Kyu Ko Won-Young Lee Seong-Bo Kim Kyu-Wan Lee Hai-Soo Chun 《Korean Journal of Chemical Engineering》2001,18(6):961-964
Biomass has became an important renewable alternative energy resource. Million tons of food sludge, which is difficult to
handle because of its rank smell and water content, is generated in Korea. Thermochemical conversion is one way to convert
biomass to energy; it can be divided into carbonization, liquefaction, and gasification. Carbonization of food waste was carried
out in a conventional stainless steel autoclave of 2 L capacity at different temperatures. Since gasification produces hydrogen-rich
synthesis gas, which can be used for methanol synthesis, gasification of carbonized solid was studied in the fluidized-bed
gasifier. The reaction parameters in the gasification of carbonized solids were investigated.
Presented at the Int’l Symp. on Chem. Eng. (Cheju, Feb. 8–10, 2001), dedicated to Prof. H. S. Chun on the occasion of his
retirement from Korea University. 相似文献
185.
Jooho Moon Masanobu Awano Kunihiro Maeda 《Journal of the American Ceramic Society》2001,84(11):2531-2536
Well-defined La2 Sn2 O7 with a phase-pure pyrochlore structure was produced by hydrothermal synthesis at temperatures as low as 200°C. Production of phase-pure La2 Sn2 O7 requires a pH above 10, and higher pH accelerates the crystallization process. The synthesis produced spherical particles of average particle size ∼0.59 μm (±0.12) and surface area ∼14.1 m2 /g. SEM and TEM observation for morphologic evolution and kinetic analysis during crystallization indicated that La2 Sn2 O7 formation probably proceeds via a two-step reaction. First a transient dissolution–precipitation occurs. Then the primary crystallites aggregate because of their colloidal instability, and heterocoagulation with the lanthanum hydrous oxide precursor particles also occurs. The sluggish reaction rate at the later stage of reaction is characterized by an in situ transformation, where the soluble tin species is diffused through the porous La2 Sn2 O7 aggregates to react with entrapped lanthanum precursors. 相似文献
186.
OTS (Operator Training System) is becoming popular for the safe and effective operation of chemical processes and control
systems. This paper outlines the total hardware system superstructure and software modules of yOTS (Yonsei Operator Training
System) which we developed. yOTS is a network based multi-training system composed of a workstation-based server module and
PC-based user modules. The user module has a DCS-like user interface and sends data to OM (yOTS Manager) over the network.
Reliability and stability are essential for the successful development of distributed OTS.State-of-the-art technologies of efficiency and stability are mainly considered in this paper. yOTS is superior to other OTS in its ease of
handling discrete events, managing process models, expanding module functionality and multi-training over the network. The
structure of yOTS and core algorithm for a multiple trainer over the network is also presented. A batch process example is
used to illustrate the proposed advantages of yOTS. 相似文献
187.
Correlation between the electronic structure and surface acidity of TiO2–SO4
2– with different SO4
2– amounts has been investigated by means of NH3-TPD, NH3-FT-IR and XPS. With the increase of sulfate loadings, the shift of binding energies of O 1s in hydroxyl and Ti 2p2/3 increases and is proportional to total acidity. A linear relation is obtained between Ti 2p binding energy shift and Lewis acid sites, while the shift in O 1s binding energy is attributed both to the generation of NH3 hydrogen bond and of Brønsted acid sites. Accordingly, the results obtained from XPS measurements provide evidence that the ammonia adsorption sites are attributed to the decrease of electron density of O 1s in hydroxyl (Brønsted type and H bonded) and Ti 2p2/3 (Lewis type) by inductive effect of the neighboring sulfate ion. 相似文献
188.
A. K. M. Fazle Kibria Young Hwan Mo Min Hee Yun Moon J. Kim Kee Suk Nahm 《Korean Journal of Chemical Engineering》2001,18(2):208-214
Multi-wall carbon nanotubes (MWNTs) were synthesized by catalytic decomposition of acetylene over Fe, Ni and Fe-Ni bimetallic catalysts supported on alumina under various controlled conditions. The growth density and diameter of CNTs were markedly dependent on the activation time of catalysts in H2 atmosphere, reaction time, reaction temperature, flow rate of acetylene, and catalyst composition. Bimetallic catalysts were apt to produce narrower diameter of CNTs than single metal catalysts. For the growth of CNTs at 600 ‡C under 10/100 seem flow of C2H2/H2 mixture, the narrowest diameter about 20 nm was observed at the reaction time of 1 h for 20Fe : 20Ni : 60Al2O3 catalyst, but at that of 1.5 h for 10Fe : 30Ni : 60Al2O3 catalyst. It was considered that the diameter and density of CNTs decreased with the increase of the growth time mainly due to hydrogen etching. The growth of CNTs followed the tip growth mode. 相似文献
189.
An-Ting Chien Prabhakar V. Gulgunje Han Gi Chae Aniruddha S. Joshi Jaeyun Moon Bo Feng G.P. Peterson Satish Kumar 《Polymer》2013
Bi-component fibers typically combine multiple functions that arise from at least two distinct components. As a result, these fibers can incorporate carbon nanotubes, which impart specific and controllable mechanical, electrical, and thermal transport properties to the fibers. Using gel spinning, sheath-core polyacrylonitrile–polyacrylonitrile/carbon nanotube bi-component fibers with a diameter of less than 20 μm and carbon nanotube concentrations of up to 10 wt% were produced. In these fibers, the carbon nanotubes were well dispersed and aligned along the fiber axis. The fibers exhibited a tensile strength as high as 700 MPa, and a tensile modulus as high as 20 GPa, as well as enhanced electrical and thermal conductivities when compared to the fibers without carbon nanotubes. 相似文献
190.
The effects of pre-annealing on the microstructure development and piezoelectric properties for 0.95(K0.5Na0.5)NbO3–0.05LiSbO3 (0.95KNN–0.05LS) ceramics were investigated. The pre-annealing suppressed the abnormal grain growth in both the undoped and Mn-doped 0.95KNN–0.05LS ceramics. The pre-annealed samples possessed smaller abnormal grains, larger matrix grains, and a broader grain size distribution compared to the samples sintered without a pre-annealing step. The pre-annealed samples presented better dielectric and piezoelectric properties, a larger dielectric constant (εr) and electromechanical coupling factor (kp), and a smaller dielectric loss factor (tan δ). 相似文献