全文获取类型
收费全文 | 1204篇 |
免费 | 5篇 |
国内免费 | 20篇 |
专业分类
电工技术 | 6篇 |
综合类 | 5篇 |
化学工业 | 443篇 |
金属工艺 | 147篇 |
机械仪表 | 12篇 |
建筑科学 | 3篇 |
矿业工程 | 7篇 |
能源动力 | 250篇 |
轻工业 | 3篇 |
水利工程 | 2篇 |
石油天然气 | 1篇 |
武器工业 | 1篇 |
无线电 | 33篇 |
一般工业技术 | 243篇 |
冶金工业 | 40篇 |
原子能技术 | 7篇 |
自动化技术 | 26篇 |
出版年
2023年 | 141篇 |
2022年 | 50篇 |
2021年 | 17篇 |
2020年 | 115篇 |
2019年 | 123篇 |
2018年 | 6篇 |
2017年 | 53篇 |
2016年 | 51篇 |
2015年 | 59篇 |
2014年 | 98篇 |
2013年 | 59篇 |
2012年 | 41篇 |
2011年 | 20篇 |
2010年 | 22篇 |
2009年 | 48篇 |
2008年 | 13篇 |
2007年 | 41篇 |
2006年 | 48篇 |
2005年 | 27篇 |
2004年 | 11篇 |
2003年 | 17篇 |
2002年 | 23篇 |
2001年 | 22篇 |
2000年 | 16篇 |
1999年 | 22篇 |
1998年 | 9篇 |
1997年 | 3篇 |
1996年 | 8篇 |
1995年 | 10篇 |
1994年 | 9篇 |
1993年 | 7篇 |
1992年 | 6篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 2篇 |
1988年 | 8篇 |
1987年 | 12篇 |
排序方式: 共有1229条查询结果,搜索用时 468 毫秒
1.
《Carbon》2015
Fe2O3 nanorod/carbon nanofiber (CNF) composites were prepared by the electrochemical deposition of Fe2O3 on a web of CNFs, which was then used as a free-standing anode. The conductive, three-dimensional structure of the CNF web allowed for the electrodeposition of the Fe2O3 nanorods, while its high conductivity made it possible to use the composite as a free-standing electrode in lithium-ion batteries. In addition, it was easy and cheap to fabricate by a simplification of a process of cell preparation. The nanorod-like Fe2O3 structures could only be electrodeposited on the CNFs; flake-like Fe2O3 was formed on flat conductive glass substrates. It can be attributed to the different growth mechanism of Fe2O3 on the CNFs because of the large number of reaction sites on the CNFs, differences in the precursor concentration and diffusivity within the CNF web. The formation of aggregates of the Fe2O3 particles on thicker CNFs also indicated that the CNFs had determined the Fe2O3 growth mechanism. The synthesised Fe2O3/CNF composite electrode exhibited stable rate capacities at different current densities. This suggested that CNF-based composite did not exhibit the intrinsic disadvantages of Fe2O3. Finally, carbon coatings were deposited on the Fe2O3/CNF composites to further improve their electronic conductivity and rate capability. 相似文献
2.
《International Journal of Hydrogen Energy》2020,45(7):4054-4064
The feasibility of microbial hydrogen consumption to mitigate the hydrogen embrittlement (HE) under different cathodic potentials was evaluated using the Devanathan-Stachurski electrochemical test and the hydrogen permeation efficiency η. The hydrogen permeation efficiency η in the presence of strain GA-1 was lower than that in sterile medium. The cathodic potential inhibited the adherence of strain GA-1 to AISI 4135 steel surface, thereby reducing the hydrogen consumption of strain GA-1. The adherent GA-1 cells were capable of consuming ‘cathodic hydrogen’ and reducing the proportions of absorbed hydrogen, indicating that it is theoretically possible to control HE by hydrogen-consuming microbes. 相似文献
3.
《Journal of power sources》2006,160(1):657-661
The cathode-active materials, layered Li[Ni0.333Co0.333Mn0.293Al0.04]O2−zFz (0 ≤ z ≤ 0.1), were synthesized from a sol–gel precursor at 900 °C in air. The influence of Al–F co-substitution on the structural and electrochemical properties of the as-prepared samples was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and electrochemical experiments. The results showed that Li[Ni0.333Co0.333Mn0.293Al0.04]O2−zFz has a typical hexagonal structure with a single phase, the particle sizes of the samples tended to increase with increasing fluorine content. It has been found that Li[Ni0.333Co0.333Mn0.293Al0.04]O1.95F0.05 showed an improved cathodic behavior and discharge capacity retention compared to the undoped samples in the voltage range of 3.0–4.3 V. The electrodes prepared from Li[Ni0.333Co0.333Mn0.293Al0.04]O1.95F0.05 delivered an initial discharge capacity of 158 mAh−1 g and an initial coulombic efficiency is 91.3%, and the capacity retention at the 20th cycle was 94.9%. Though the F-doped samples had lower initial capacities, they showed better cycle performances compared with F-free samples. Therefore, this is a promising material for a lithium-ion battery. 相似文献
4.
B. Wilthan G. Pottlacher 《稀有金属(英文版)》2006,25(5):592-596
1. Introduction Metal working industry needs accurate thermo- physical properties of liquid metals and alloys as input data for different simulation routines to im- prove the performance of their products. Within this paper we continue the systematic investigation of the dependence of emissivity of binary alloys on the relative concentration of the constituent elements (for a previous paper see [1]). 2. Experimental method A fast ohmic pulse heating technique is applied to heat metallic wire-s… 相似文献
5.
《Materials Letters》2007,61(4-5):1154-1157
Lanthanum (La), a rare earth element with anticoagulative and antiphlogistic function, was added into the medical grade 316L stainless steel in order to improve its biocompatibility. The corrosion resistance of the La added 316L steel in two different simulated body fluids, simulated blood plasma and Hank's solution, was evaluated. The result showed that the addition of La in the steel could largely affect the corrosion behavior of the steel. The steel with 0.01% La showed the widest passive region and the best resistance to pitting attack, within the addition range of La from 0.01% to 0.08%. The corrosion resistance improvement of La added 316L stainless steel is probably due to the effect of La on the purification of the steel, the modification of inclusions, and the passive film formation in the simulated body fluids. 相似文献
6.
7.
《Synthetic Metals》2005,148(3):237-243
Self-assembled polyaniline nanofibers doped with 2-acrylamido-2-methyl-1-propanesulfonic acid were prepared by oxidative polymerization of aniline in the presence of a nonionic surfactant. These nanofibers were dedoped to the semiconducting emeraldine base and then redoped to the metallic emeraldine hydrochloride. It was possible to introduce a different dopant anion from that used in the initial synthesis with no significant changes in fiber morphology or diameter, as observed by scanning electron microscopy (SEM). The method of sample preparation for SEM significantly affected the observed morphology. Deposition from aqueous dispersions resulted primarily in nanofibers that ranged in diameter from 28 to 82 nm (average: 56 nm), whereas drying to solid powder resulted in a less fibrous material. UV–vis–NIR absorbance spectroscopy indicated that the electronic structure of the emeraldine base nanofibers was identical to bulk emeraldine base obtained by conventional synthesis. Estimates from X-ray diffraction data suggested that the fractional crystallinity of emeraldine hydrochloride nanofibers did not differ significantly from the bulk powder. 相似文献
8.
为了得到高质量的纳米薄膜,对直流磁控溅射法制备Ni-Ti薄膜工艺进行了研究。采用单晶硅和玻璃两种基体材料,并在不同的基体温度、晶化温度、溅射功率等条件下制备薄膜。之后对薄膜进行了XRD,SEM分析。分析结果表明:薄膜成分、厚度、表面形貌、致密度与溅射功率、基体温度、晶化温度、基体材料密切相关。并根据实验结果给出优化的纳米Ni-Ti薄膜制备工艺。 相似文献
9.
Boshi Tian Shaohua Liu Chenghao Yu Shikai Liu Shuming Dong Lili Feng Narisu Hu Piaoping Yang 《Advanced functional materials》2023,33(25):2300818
As a less O2-dependent photodynamic therapy (PDT), type I PDT is an effective approach to overcome the hypoxia-induced low efficiency against solid tumors. However, the commonly used metal-involved agents suffer from the long-term biosafety concern. Herein, a metal-free type I photosensitizer, N-doped carbon dots/mesoporous silica nanoparticles (NCDs/MSN, ≈40 nm) nanohybrid with peroxidase (POD)-like activity for synergistic PDT and enzyme-activity treatment, is developed on gram scale via a facile one-pot strategy through mixing carbon source and silica precursor with the assistance of template. Benefiting from the narrow bandgap (1.92 eV) and good charge separation capacity of NCDs/MSN, upon 640 nm light irradiation, the excited electrons in the conduction band can effectively generate O2•− by reduction of dissolved O2 via a one-electron transfer process even under hypoxic conditions, inducing apoptosis of tumor cells. Moreover, the photoinduced O2•− can partially transform into more toxic •OH through a two-electron reduction. Moreover, the POD-like activity of NCDs/MSN can catalyze the endogenous H2O2 to •OH in the tumor microenvironment, further synergistically ablating 4T1 tumor cells. Therefore, a mass production way to synthesize a novel metal-free type I photosensitizer with enzyme-mimic activity for synergistic treatment of hypoxic tumors is provided, which exhibits promising clinical translation prospects. 相似文献
10.
《材料科学技术学报》2019,35(10):2345-2356
The corrosion kinetics and patina (corrosion products) layer evolution of galvanized steel submitted to wet/dry cyclic corrosion test in a simulated coastal-industrial atmosphere was investigated. The results show that zinc coating has a greater corrosion rate during the initial period and a lower corrosion rate during the subsequent period, and the patina composition and structure can greatly affect the corrosion kinetics evolution of zinc coating. Moreover, Zn5(OH)6(CO3)2 and Zn4(OH)6SO4 are identified as the main stable composition and exhibit an increasing relative amount; while Zn12(OH)15Cl3(SO4)3 cannot stably exist and diminish in the patina layer as the corrosion develops. 相似文献