全文获取类型
收费全文 | 463篇 |
免费 | 7篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 1篇 |
综合类 | 1篇 |
化学工业 | 137篇 |
金属工艺 | 93篇 |
机械仪表 | 14篇 |
建筑科学 | 2篇 |
矿业工程 | 4篇 |
能源动力 | 63篇 |
轻工业 | 1篇 |
石油天然气 | 1篇 |
无线电 | 22篇 |
一般工业技术 | 104篇 |
冶金工业 | 20篇 |
原子能技术 | 2篇 |
自动化技术 | 15篇 |
出版年
2023年 | 46篇 |
2022年 | 8篇 |
2021年 | 19篇 |
2020年 | 42篇 |
2019年 | 30篇 |
2018年 | 7篇 |
2017年 | 19篇 |
2016年 | 21篇 |
2015年 | 22篇 |
2014年 | 34篇 |
2013年 | 28篇 |
2012年 | 26篇 |
2011年 | 19篇 |
2010年 | 4篇 |
2009年 | 19篇 |
2008年 | 3篇 |
2007年 | 15篇 |
2006年 | 29篇 |
2005年 | 5篇 |
2004年 | 8篇 |
2003年 | 11篇 |
2002年 | 6篇 |
2001年 | 16篇 |
2000年 | 6篇 |
1999年 | 6篇 |
1996年 | 2篇 |
1995年 | 2篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1991年 | 2篇 |
1990年 | 2篇 |
1988年 | 2篇 |
1987年 | 7篇 |
1986年 | 6篇 |
1976年 | 1篇 |
排序方式: 共有480条查询结果,搜索用时 31 毫秒
21.
《International Journal of Hydrogen Energy》2020,45(7):4390-4402
TiO2–CdS nanotubes (NTs) were used for the first time as a support to load metal nanoparticles (NPs) for the hydrolysis of ammonia borane (AB) which is a new strategy. The TiO2–CdS NTs support was first synthesized using a hydrothermal method, and then the CuNi NPs were loaded using a liquid-phase reduction method. The synthesized samples were characterized by XRD, SEM-EDS, TEM, XPS, ICP, UV–Vis, and PL analyses. The characterization results show that the CuNi NPs existed in the form of an alloy with a size of ~1.2 nm and uniformly dispersed on the support. Compared with their single metal counterparts, the bimetallic CuNi-supported catalysts showed a higher catalytic activity in the hydrolysis of AB under visible-light irradiation: Cu0·45Ni0·55/TiO2–CdS catalyst had the fastest hydrogen evolution rate with a high conversion frequency (TOF) of 25.9 molH2·molcat−1 min−1 at 25 °C and low activation energy of 32.8 kJ mol−1. Cu0.45Ni0.55/TiO2–CdS catalyst showed good recycle performance, maintaining 99.3% and 85.6% of the original hydrogen evolution rate even after five and ten recycles, respectively. Strong absorption of visible light, improved electron–hole separation efficiency, and metal synergy between Cu and Ni elements played a crucial role in improving the catalytic hydrolysis performance of AB. The catalyst prepared in this study provides a new strategy for the application of photocatalysts. 相似文献
22.
23.
24.
A hydrometallurgical treatment involving solvent extraction of zinc using di-2-ethylhexyl phosphoric acid (D2EHPA) has been investigated to recover zinc from an industrial leach residue. The residue was leached with sulfuric acid producing leach liquor which was subjected to solvent extraction for enrichment of zinc and removal of impurities. Operating variables, such as pH, D2EHPA concentration, temperature, aqueous/organic (A/O) phase ratio, tri-butyl phosphate (TBP) concentration and sodium sulfate (Na2SO4) concentration in aqueous phase were studied. Practically, all zinc was extracted from the aqueous solution at pH 2.5 with 20% w/w D2EHPA in kerosene. Increasing either TBP concentration up to 5%, or Na2SO4 concentration up to 0.2 M, increased the zinc extraction. Zinc could be extracted at one theoretical stage at A/O of 1/1, as calculated by McCabe–Thiele method. 相似文献
25.
《Intermetallics》2014
In this work, first principles calculation of structural, electronic magnetic and elastic properties of the half-metallic ferromagnetic Heusler compound Co2MnSi are presented. We have applied the full-potential linearized augmented plane waves plus local orbitals (FP-L/APW+lo) method based on the density functional theory (DFT). For the exchange and correlation potential generalized-gradient approximation (GGA) is used. The computed equilibrium lattice parameters agree well with the available theoretical and experimental data. Elastic constants and their pressure dependence are also calculated. The calculated total magnetization of 5 μB is in excellent agreement with recent experiments. We also presented the thermal effects using the quasi-harmonic Debye model, in which the lattice vibrations are taken into account. Temperature and pressure effects on the structural parameters, heat capacities, entropy, thermal expansion coefficient, and Debye temperatures are determined from the non-equilibrium Gibbs functions. 相似文献
26.
J.A. Canteli J.L. Cantero N.C. Marín B. Gómez E. Gordo M.H. Miguélez 《Journal of Materials Processing Technology》2010,210(1):122-128
This work is focused on the cutting performance of a new cermet based on high-speed steel (HSS) matrix with hard phase TiCN. The processing route to manufacture the cermet M2 + 50 vol.% TiCN is described. Orthogonal cutting tests, carried out in a lathe showed the ability of the new cermet to achieve turning operations, showing reasonably wear resistance performing dry cutting operations. Tool life was significantly increased, when the cermet was compared with the reference material M2 without reinforcement and with commercial HSS M2. Evolution of flank wear and chipping wear, being the dominant wear patterns, were analysed. 相似文献
27.
Tai Yang Qiang Li Chunyong Liang Xinghua Wang Chaoqun Xia Hongshui Wang Fuxing Yin Yanghuan Zhang 《International Journal of Hydrogen Energy》2018,43(18):8877-8887
Ternary alloys with the nominal composition of Mg24Y3M (M = Ni, Co, Cu, Al) have been fabricated by using vacuum induction melting method. Their microstructure and phase composition are characterized by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The isothermal hydrogen absorption and desorption kinetics are measured by a Sievert's-type apparatus. The dehydrogenation behaviors of the full hydrogenated alloys are also analyzed by differential scanning calorimetry (DSC) method. Results show that each and every alloy has a distinct multiphase structure containing the main phase Mg24Y5 and some amount of Mg. Intermetallic compounds of YCo2 and Al2Y are detected in the M = Co and M = Al alloy, while long-period stacking ordered (LPSO) phase can be also observed in M = Ni and M = Cu alloy. The hydrogen absorption and desorption kinetics shows a decreased trend in the following order: (M = Ni) > (M = Al) > (M = Co) > (M = Cu). The M = Ni alloy has the best hydrogen storage performance among the investigated alloys. The dehydrogenation activation energy (Ea) of the M = Ni alloy decreases to 66 kJ/mol, and its decomposition peak temperature is also reduced to 313 °C. Moreover, the p–c–T (pressure-composition isotherms) curves of the studied alloys are also discussed. 相似文献
28.
Perovskite structured La2Ti2O7 catalyst prepared by polymerized complex method was characterized and examined the photocatalytic activity by decomposing an azo dyestuff, Reactive Red 22, in aqueous solutions under UV irradiation. La2Ti2O7 powders prepared by polymerized complex method exhibit higher surface areas, better homogeneity and are more sensitive to solution than those prepared by solid-state method. The first derivatives of UV–vis DRS patterns confirmed the complete crystallization of La2Ti2O7 sintered at temperatures higher than 900 °C. The effects of sintering temperature of catalyst and solution pH of photocatalytic reaction were studied. The photocatalytic decomposition of Reactive Red 22 per unit surface area was found to be higher for experiments using La2Ti2O7 than using TiO2. However, the electron–hole recombination was found to be more obvious for La2Ti2O7 than for TiO2 because the network of metal cations constructed within La2Ti2O7 enhances the mobility of photogenerated electrons and holes. 相似文献
29.
Nanostructured composite ceramic coatings (NCs) were deposited by supersonic plasma spraying (SPS) technique. The microstructures of NCs were characterized using scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscope (TEM). The results showed that the microstructure of NCs exhibited a bimodal distribution consisting of fully melted regions (FM regions) and partially melted regions (PM regions). With the spray power increasing, the proportions of FM regions and PM regions both increased, but no distinct laws were found. The measured data of elastic modulus, micro-hardness and fracture toughness were analyzed using Weibull statistics. The results showed that these micromechanical properties followed Weibull distribution and presented a characteristic of bimodal distribution. 相似文献
30.
《Materials Letters》2005,59(19-20):2519-2522
Hollow calcium carbonate (CaCO3) is a potential component in many industrial fields such as plastics, rubbers, papermaking, and drug delivery. This paper described a novel approach to synthesize hollow CaCO3 particles by using bubble as template via passing CO2 bubbles into calcium chloride (CaCl2) solution in the presence of ammonia (NH3) at 27 °C. The CO2 bubble is not only the reactive material, but also the template of hollow particles. The newly-formed primary particles attach to bubbles and form a solid shell. After filtering and drying the hollow CaCO3 particles were obtained. Physical characteristics of the precipitate were evaluated using scanning electron microscopy (SEM) and X-ray diffraction (XRD). 相似文献