全文获取类型
| 收费全文 | 4110篇 |
| 免费 | 52篇 |
| 国内免费 | 6篇 |
专业分类
| 电工技术 | 74篇 |
| 综合类 | 3篇 |
| 化学工业 | 881篇 |
| 金属工艺 | 128篇 |
| 机械仪表 | 229篇 |
| 建筑科学 | 95篇 |
| 矿业工程 | 1篇 |
| 能源动力 | 149篇 |
| 轻工业 | 346篇 |
| 水利工程 | 14篇 |
| 石油天然气 | 1篇 |
| 无线电 | 718篇 |
| 一般工业技术 | 842篇 |
| 冶金工业 | 240篇 |
| 原子能技术 | 43篇 |
| 自动化技术 | 404篇 |
出版年
| 2024年 | 56篇 |
| 2023年 | 45篇 |
| 2022年 | 57篇 |
| 2021年 | 89篇 |
| 2020年 | 101篇 |
| 2019年 | 105篇 |
| 2018年 | 109篇 |
| 2017年 | 116篇 |
| 2016年 | 132篇 |
| 2015年 | 111篇 |
| 2014年 | 160篇 |
| 2013年 | 259篇 |
| 2012年 | 233篇 |
| 2011年 | 306篇 |
| 2010年 | 211篇 |
| 2009年 | 228篇 |
| 2008年 | 212篇 |
| 2007年 | 172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 | 57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 |
| 1953年 | 2篇 |
排序方式： 共有4168条查询结果，搜索用时 15 毫秒
991.
Electrospinning has received a lot of attention in recent years because it can create nonwoven nanofiber webs with high surface area and porosity. However, the typical needle and syringe-based electrospinning systems feature poor productivity that has limited their usefulness in the industrial field. Here, current developments in the creation of nanofibers employing nonconventional electrospinning methods, such as needleless electrospinning and syringeless electrospinning, are examined. These alternate electrospinning techniques, which are dependent on numerous polymer droplets of varied shapes, have the potential to match the productivity required for industry-scale manufacturing of nanofibers. Additionally, they make it possible to produce nanofibers that are difficult to spin using traditional techniques, like electrospinning of colloidal suspensions. 相似文献
992.
Hyunjun Park Junho Lee Cheolwoo Kim Kyoungil Moon Sangsub Kim Sungwook Mhin 《International Journal of Applied Ceramic Technology》2023,20(2):1002-1009
This work presents the effect of oxynitriding process at different temperature on the corrosion resistance and wear behavior of the quenching-and-tempering-treated AISI 4140 steel. The AISI 4140 was plasma nitrided at 500°C. Subsequently, the plasma oxynitriding was performed on the nitrided AISI 4140 at different temperatures under H2O atmosphere. Microstructure and phases of the plasma-oxynitrided samples are investigated, indicating that phase formation of the oxide layer is strongly dependent on processing temperature during plasma oxynitriding: Formation of Fe3O4 is preferred over Fe2O3 at lower processing temperature. Also, it is believed that ε-Fe2–3N phase formed by nitriding process plays an important role to promote the formation of Fe3O4 phase during plasma oxynitriding. In order to investigate the mechanical, wear, and corrosion properties of the plasma-oxynitrided samples, Vickers hardness, friction coefficient, and potentiodynamic curves are evaluated, respectively. Compared to a plasma-nitrided sample, the Vickers hardness of the plasma-oxynitrided sample at optimal processing temperature shows a slight decrease of the hardness, but, improved wear and corrosion resistances were observed. It is suggested that wear and corrosion resistance of the oxynitrided sample is strongly dependent on the volume fraction of Fe3O4 phase in the oxide layer. 相似文献
993.
Kim Jin Tae Lee Seung Beom Son Moon Jeong Zhou Yimeng Qiu Shuai Park Ho Jin Jeon Dong Hyeon Kim Young-Jun Lee Hong Jin 《Food science and biotechnology》2023,32(7):997-1003
Food Science and Biotechnology - Perilla frutescens is an annual herbaceous plant widely cultivated for oil production in China, Japan, and Korea. In this study, we investigated the effect of... 相似文献
994.
Amar. M. Patil Sunil Moon Arti A. Jadhav Jongwoo Hong Keonwook Kang Seong Chan Jun 《Advanced functional materials》2023,33(46):2305264
The inferior electrical conductivity of conventional electrodes and their slow charge transport impose limitations on the electrochemical performance of supercapacitors (SCs) using those electrodes, necessitating strategies to overcome the limitations. An in situ Ag ion-incorporated cation-exchanged bimetallic sulfide/metal oxide heterostructure (Ag-Co9-xFexS8@α-FexOy) is synthesized using a two-step hydrothermal method. The coordination bond formation and Ag nanoparticle (NP) incorporation improve the electrical conductivity and adhesion of the heterostructure and reduce its interface resistance and volume expansion throughout the charge/discharge cycles. Density functional theory investigations indicate that the remarkable interlayer and interparticle conductivities of the heterostructure resulting from Ag doping have changed its electronic states, leading to an enhanced electrical conductivity. The optimized electrode has an excellent specific capacity (213.6 mA h g−1 at 1 A g−1) and can maintain 93.2% capacity retention with excellent Coulombic efficiency over 20 000 charge/discharge cycles. A flexible solid-state extrinsic pseudocapacitor (EPSC) is fabricated using Ag-Co9-xFexS8@α-FexOy and Ti3C2TX electrodes. The EPSC has specific and volumetric capacitances of 259 F g−1 and 2.7 F cm−3 at 0.7 A g−1, respectively, an energy density of 80.9 Wh kg−1 at 525 W kg−1, and a capacity retention of 92.8% over 5000 charge/discharge cycles. 相似文献
995.
Anthony Vallace;Zachary S. Campbell;Hyun June Moon;William J. Koros;Christopher W. Jones;Ryan P. Lively; 《Small (Weinheim an der Bergstrasse, Germany)》2024,20(46):2401422
Silica-supported amine absorbents, including materials produced by tethering aminosilanes or infusion of poly(ethyleneimine), represent a promising class of materials for CO2 capture applications, including direct air and point source capture. Various silica surface treatments and functionalization strategies are explored to enhance stability and CO2 uptake in amine-based solid sorbent systems. Here, the synthesis and characterization of novel vinyltrimethoxysilane-treated Santa Barbara Amorphous-15 (SBA-15) supports and the corresponding enhancement in CO2 uptake compared to various SBA-15-based control supports are presented. The relationship between CO2 diffusion and amine efficiency in these systems is explored using a previously reported kinetic model. The synthesized materials are characterized with CO2 and H2O isotherms, diffuse reflectance infrared Fourier transform spectroscopy, 1H T1–T2 relaxation correlation NMR, and rapid thermal cycling experiments. The novel support materials are shown to enable high amine efficiencies, approaching a fourfold improvement over standard SBA-15-supported amines, while simultaneously exhibiting excellent stability when cycled rapidly under humid conditions. As the poly(ethyleneimine) loadings are held constant across the various samples, enhancements in CO2 uptake are attributed to differences in the way the poly(ethyleneimine) interacts with the support surface. 相似文献
996.
997.
Jiyoung Moon;Yash Mehta;Kenan Gundogdu;Franky So;Qing Gu; 《Advanced materials (Deerfield Beach, Fla.)》2024,36(20):2211284
Hybrid metal-halide perovskites (MHPs) have shown remarkable optoelectronic properties as well as facile and cost-effective processability. With the success of MHP solar cells and light-emitting diodes, MHPs have also exhibited great potential as gain media for on-chip lasers. However, to date, stable operation of optically pumped MHP lasers and electrically driven MHP lasers—an essential requirement for MHP laser's insertion into chip-scale photonic integrated circuits—is not yet demonstrated. The main obstacles include the instability of MHPs in the atmosphere, rudimentary MHP laser cavity patterning methods, and insufficient understanding of emission mechanisms in MHP materials and cavities. This review aims to provide a detailed overview of different strategies to improve the intrinsic properties of MHPs in the atmosphere and to establish an optimal MHP cavity patterning method. In addition, this review discusses different emission mechanisms in MHP materials and cavities and how to distinguish them. 相似文献
998.
Minju Kim;Guogao Zhang;Segeun Jang;Sanghyeok Lee;Zhigang Suo;Sang Moon Kim; 《Advanced materials (Deerfield Beach, Fla.)》2024,36(14):2308288
In a hydrogen fuel cell, an electrolyte membrane conducts protons, but blocks electrons, hydrogen molecules, and oxygen molecules. The fuel cell often runs unsteadily, resulting in fluctuating water production, causing the membrane to swell and contract. The cyclic deformation can cause fatigue crack growth. This paper describes an approach to develop a fatigue-resistant polymer electrolyte membrane. The membrane is prepared by forming an interpenetrating network of a plastic electrolyte and a rubber. The former conducts protons, and the latter enhances fatigue resistance. The introduction of the rubber modestly reduces electrochemical performance, but significantly increases fatigue threshold and lifespan. Compared to pristine plastic electrolyte, Nafion, an interpenetrating network of Nafion and perfluoropolyether (PFPE) reduces the maximum power density by 20%, but increases the fatigue threshold by 175%. Under the wet/dry accelerated stress test, the fuel cell with the Nafion-PFPE membrane has a lifespan 1.7 times that of a fuel cell with the Nafion membrane. 相似文献
999.
Fu Z Yang HK Moon BK Choi BC Jeong JH 《Journal of nanoscience and nanotechnology》2011,11(2):1629-1631
In this paper, CaSnO3:Eu3+ nanocrystals were prepared by hydrothermal synthesis method. The influence of different molar ratio of Ca:Sn on structure of CaSnO3:Eu3+ was investigated by using X-ray powder diffraction (XRD). Well-crystallized and phase-pure CaSnO3:Eu3+ particles of approximately 90 nm in size can be readily obtained at 900 degrees C. Furthermore, photoluminescence characterization of the Eu(3+)-doped CaSnO3 nanocrystals was performed and discussed. The emission peak situated at 618 nm showing prominent and bright red light is due to the 5D0-7F2 electric dipole transition. The excellent luminescence properties make it possible as a good candidate for PDP application. 相似文献
1000.
Tang SQ Moon SJ Park KH Paek SH Chung KW Bae S 《Journal of nanoscience and nanotechnology》2011,11(1):82-89
Magnetic properties of 200 nm ferrimagnetic CoFe2O4 nanoparticles before and after coating with TEOS were explored and compared to soft ferrimagnetic MgFe2O4 nanoparticles (200 nm) to evaluate the feasibility as an in-vitro GMR SV (giant magnetoresistance spin-valve) biosensor agent for single molecular detection (SMD). It was found that the magnetic degradation (or variation) of TEOS coated CoFe2O4 and MgFe2O4 nanoparticles are dominantly affected by the chemical dispersion process, which is carried out in the oleic acid (OA), oleylamine (OL), or OA+OL surfactant, before starting major coating process. In addition, the TEOS coating thickness controlled by TEOS concentration and pH level in the buffer solution prominently influenced on the magnetic degradation of TEOS coated nanoparticles. According to the experimental analysis results, the magnetic degradation of TEOS coated nanoparticles is mainly attributed to the variation of particle dipole interaction caused by the degree of particle aggregation depending on TEOS coating process conditions. The TEOS coated CoFe2O4 nanoparticles exhibited a higher magnetic stability for a GMR biosensor agent, e.g., small variation of remnant magnetization, saturation magnetization and magnetic coercivity, than that of MgFe2O4 nanoparticles at the different coating process conditions. The physical and chemical analysis confirmed that this is primarily due to its higher magnetic anisotropy. The experimentally verified high biocompatibility as well as the stably maintained magnetic properties of TEOS coated CoFe2O4 nanoparticles demonstrate that CoFe2O4 nanoparticles can be considered as one of the promising ferrimagnetic nanoparticle sensor agent for an SMD GMR SV biosensor. 相似文献