全文获取类型
收费全文 | 89017篇 |
免费 | 1192篇 |
国内免费 | 426篇 |
专业分类
电工技术 | 816篇 |
综合类 | 2335篇 |
化学工业 | 12449篇 |
金属工艺 | 4862篇 |
机械仪表 | 3132篇 |
建筑科学 | 2449篇 |
矿业工程 | 572篇 |
能源动力 | 1317篇 |
轻工业 | 3911篇 |
水利工程 | 1320篇 |
石油天然气 | 372篇 |
无线电 | 9720篇 |
一般工业技术 | 17365篇 |
冶金工业 | 3452篇 |
原子能技术 | 296篇 |
自动化技术 | 26267篇 |
出版年
2023年 | 56篇 |
2022年 | 115篇 |
2021年 | 183篇 |
2020年 | 132篇 |
2019年 | 178篇 |
2018年 | 14616篇 |
2017年 | 13484篇 |
2016年 | 10085篇 |
2015年 | 729篇 |
2014年 | 412篇 |
2013年 | 529篇 |
2012年 | 3422篇 |
2011年 | 9705篇 |
2010年 | 8487篇 |
2009年 | 5779篇 |
2008年 | 7008篇 |
2007年 | 8020篇 |
2006年 | 306篇 |
2005年 | 1390篇 |
2004年 | 1287篇 |
2003年 | 1333篇 |
2002年 | 673篇 |
2001年 | 178篇 |
2000年 | 268篇 |
1999年 | 124篇 |
1998年 | 280篇 |
1997年 | 183篇 |
1996年 | 141篇 |
1995年 | 115篇 |
1994年 | 90篇 |
1993年 | 79篇 |
1992年 | 69篇 |
1991年 | 66篇 |
1990年 | 32篇 |
1989年 | 31篇 |
1988年 | 46篇 |
1987年 | 34篇 |
1976年 | 46篇 |
1968年 | 52篇 |
1967年 | 39篇 |
1966年 | 43篇 |
1965年 | 47篇 |
1963年 | 30篇 |
1960年 | 31篇 |
1959年 | 38篇 |
1958年 | 37篇 |
1957年 | 36篇 |
1956年 | 36篇 |
1955年 | 66篇 |
1954年 | 70篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
941.
Qiyi Fang Zhepeng Zhang Qingqing Ji Siya Zhu Yue Gong Yu Zhang Jianping Shi Xiebo Zhou Lin Gu Qian Wang Yanfeng Zhang 《Nano Research》2017,10(8):2761-2771
Molybdenum ditelluride (MoTe2),which is an important transition-metal dichalcogenide,has attracted considerable interest owing to its unique properties,such as its small bandgap and large Seebeck coefficient.However,the batch production of monolayer MoTe2 has been rarely reported.In this study,we demonstrate the synthesis of large-domain (edge length exceeding 30 μm),monolayer MoTe2 from chemical vapor deposition-grown monolayer MoS2 using a chalcogen atom-exchange synthesis route.An in-depth investigation of the tellurization process reveals that the substitution of S atoms by Te is prevalently initiated at the edges and grain boundaries of the monolayer MoS2,which differs from the homogeneous selenization of MoS2 flakes with the formation of alloyed Mo-S-Se hybrids.Moreover,we detect a large compressive strain (approximately-10%) in the transformed MoTe2 lattice,which possibly drives the phase transition from 2H to 1T'at the reaction temperature of 500 ℃.This phase change is substantiated by experimental facts and first-principles calculations.This work introduces a novel route for the templated synthesis of two-dimensional layered materials through atom substitutional chemistry and provides a new pathway for engineering the strain and thus the intriguing physics and chemistry. 相似文献
942.
Fangfang Cui Xiaobo Li Qingliang Feng Jianbo Yin Lin Zhou Dongyan Liu Kaiqiang Liu Xuexia He Xing Liang Shengzhong Liu Zhibin Lei Zonghuai Liu Hailin Peng Jin Zhang Jing Kong Hua Xu 《Nano Research》2017,10(8):2732-2742
The anisotropic two-dimensional (2D) layered material rhenium disulfide (ReSe2) has attracted considerable attention because of its unusual properties and promising applications in electronic and optoelectronic devices.However,because of its low lattice symmetry and interlayer decoupling,anisotropic growth and out-of-plane growth occur easily,yielding thick flakes,dendritic structure,or flower-like structure.In this study,we demonstrated a bottom-up method for the controlled and scalable synthesis of ReSe2 by van der Waals epitaxy.To achieve controllable growth,a micro-reactor with a confined reaction space was constructed by stacking two mica substrates in the chemical vapor deposition system.Within the confined reaction space,the nucleation density and growth rate of ReSe2 were significantly reduced,favoring the large-area synthesis of ReSe2 with a uniform monolayer thickness.The morphological evolution of ReSe2 with growth temperature indicated that the anisotropic growth was suppressed at a low growth temperature (<600 ℃).Field-effect transistors employing the grown ReSe2 exhibited p-type conduction with a current ON/OFF ratio up to 10s and a hole carrier mobility of 0.98 cm2/(V.s).Furthermore,the ReSe2 device exhibited an outstanding photoresponse to near-infrared light,with responsivity up to 8.4 and 5.1 A/W for 850-and 940-nm light,respectively.This work not only promotes the large-scale application of ReSe2 in high-performance electronic devices but also clarifies the growth mechanism of low-lattice symmetry 2D materials. 相似文献
943.
Juan Peng Liqiang Liu Liguang Xu Shanshan Song Hua Kuang Gang Cui Chuanlai Xu 《Nano Research》2017,10(1):108-120
For rapid and simultaneous detection of (fluoro)quinolones, a broadly specific monoclonal antibody (mAb) that recognizes 32 (fluoro)quinolone antibiotics was prepared using a mixture of a norfloxacin derivative and a sarfloxacin derivative as the hapten. An immunochromatographic strip based on gold nanoparticles (AuNPs) was then assembled with goat anti-mouse antibody and antigen (sarfloxacin coupled to ovalbumin), used to form the C line and T line, respectively. This antigen competes with the (fluoro)quinolones in a sample incubated with mAbs labeled with AuNPs. The strip can detect 32 (fluoro)quinolones including oxolinic acid, nalidixic acid, miloxacin, pipemidic acid, piromidic acid, rosoxacin, cinoxacin, norfloxacin, pefloxacin, lomfloxacin, enofloxacin, fleroxacin, ciprofloxacin, enrofloxacin, dafloxacin, orbifloxacin, sparfloxacin, gemifloxacin, besifloxacin, balofloxacin, gatifloxacin, moxifloxacin, nadifloxacin, ofloxacin, marbofloxacin, flumequine, pazufloxacin, prulifloxacin, sarafloxacin, difloxacin, trovafloxacin, and tosufloxacin in milk within 10 min with the naked eye. The cut-off values of the strip range from 1 to 100 ng/mL and the limits of detection are 0.1–10 ng/mL. The strip does not cross-react with antibiotics including tetracycline, sulfamethazine, ampicillin, erythromycin, aflatoxin B1, or gentamicin. In short, this immunochromatographic strip is a very useful tool for the primary screening of (fluoro)quinolones in milk. 相似文献
944.
Fan Yang Mikel Abadia Chaoqiu Chen Weike Wang Le Li Lianbing Zhang Celia Rogero Andrey Chuvilin Mato Knez 《Nano Research》2017,10(1):97-107
The oxygen reduction reaction (ORR) is essential in research pertaining to life science and energy. In applications, platinum-based catalysts give ideal reactivity, but, in practice, are often subject to high costs and poor stability. Some cost-efficient transition metal oxides have exhibited excellent ORR reactivity, but the stability and durability of such alternative catalyst materials pose serious challenges. Here, we present a facile method to fabricate uniform Co x O y nanoparticles and embed them into N-doped carbon, which results in a composite of extraordinary stability and durability, while maintaining its high reactivity. The half-wave potential shows a negative shift of only 21 mV after 10,000 cycles, only one third of that observed for Pt/C (63 mV). Furthermore, after 100,000 s testing at a constant potential, the current decreases by only 17%, significantly less than for Pt/C (35%). The exceptional stability and durability results from the system architecture, which comprises a thin carbon shell that prevents agglomeration of the Co x O y nanoparticles and their detaching from the substrate. 相似文献
945.
In recent years,trap-related interfacial transport phenomena have received great attention owing to their potential applications in resistive switching devices and photo detectors.Not long ago,one new type of memristive interface that is composed of F-doped SnO2 and Bi2S3 nano-network layers has demonstrated a bivariate-continuous-tunable resistance with a swift response comparable to the one in neuron synapses and with a brain-like memorizing capability.However,the resistive mechanism is still not clearly understood because of lack of evidence,and the limited improvement in the development of the interfacial device.By combining I-V characterization,electron energy-loss spectroscopy,and firstprinciple calculation,we studied in detail the macro/micro features of the memristive interface using experimental and theoretical methods,and confirmed that its atomic origin is attributed to the traps induced by O-doping.This implies that impurity-doping might be an effective strategy for improving switching features and building new interfacial memristors. 相似文献
946.
Against general wisdom in crystallization,the nucleation of InP and Ⅲ-Ⅴ quantum dots (QDs) often dominates their growth.Systematic studies on InP QDs identified the key reason for this:the dense and tight alkanoate-ligand shell around each nanocrystal.Different strategies were explored to enable necessary ligand dynamics—i.e.,ligands rapidly switching between being bonded to and detached from a nanocrystal upon thermal agitation—on nanocrystals to simultaneously retain colloidal stability and allow appreciable growth.Among all the surface-activation reagents tested,2,4-diketones (such as acetylacetone) allowed the full growth of InP QDs with indium alkanoates and trimethylsilylphosphine as precursors.While small fatty acids (such as acetic acid) were partially active,common neutral ligands (such as fatty amines,organophosphines,and phosphine oxides) showed limited activation effects.The existing amine-based synthesis of InP QDs was activated by acetic acid formed in situ.Surface activation with common precursors enabled the growth of InP QDs with a distinguishable absorption peak between ~450 and 650 nm at mild temperatures (140-180 ℃).Furthermore,surface activation was generally applicable for InAs and Ⅲ-Ⅴ based core/shell QDs. 相似文献
947.
Nanowires with inhomogeneous heterostructures such as polytypes and periodic twin boundaries are interesting due to their potential use as components for optical,electrical,and thermophysical applications.Additionally,the incorporation of metal impurities in semiconductor nanowires could substantially alter their electronic and optical properties.In this highlight article,we review our recent progress and understanding in the deliberate induction of imperfections,in terms of both twin boundaries and additional impurities in germanium nanowires for new/enhanced functionalities.The role of catalysts and catalyst-nanowire interfaces for the growth of engineered nanowires via a three-phase paradigm is explored.Three-phase bottom-up growth is a feasible way to incorporate and engineer imperfections such as crystal defects and impurities in semiconductor nanowires via catalyst and/or interfacial manipulation."Epitaxial defect transfer"process and catalyst-nanowire interfacial engineering are employed to induce twin defects parallel and perpendicular to the nanowire growth axis.By inducing and manipulating twin boundaries in the metal catalysts,twin formation and density are controlled in Ge nanowires.The formation of Ge polytypes is also observed in nanowires for the growth of highly dense lateral twin boundaries.Additionally,metal impurity in the form of Sn is injected and engineered via third-party metal catalysts resulting in above-equilibrium incorporation of Sn adatoms in Ge nanowires.Sn impurities are precipitated into Ge bi-layers during Ge nanowire growth,where the impurity Sn atoms become trapped with the deposition of successive layers,thus giving an extraordinary Sn content (>6 at.%) in Ge nanowires.A larger amount of Sn impingement (>9 at.%) is further encouraged by utilizing the eutectic solubility of Sn in Ge along with impurity trapping. 相似文献
948.
Wei Zheng Biao Xu Lin Zhou Yilong Zhou Haimei Zheng Chenghan Sun Enzheng Shi Tanner Dale Fink Yue Wu 《Nano Research》2017,10(5):1498-1509
Thermoelectric materials,which can convert waste heat into electricity,have received increasing research interest in recent years.This paper describes the recent progress in thermoelectric nanocomposites based on solution-synthesized nanoheterostructures.We start our discussion with the strategies of improving the power factor of a given material by using nanoheterostructures.Then we discuss the methods of decreasing thermal conductivity.Finally,we highlight a way of decoupling power factor and thermal conductivity,namely,incorporating phase-transition materials into a nanowire heterostructure.We have explored the lead telluride-copper telluride thermoelectric nanowire heterostructure in this work.Future possible ways to improve the figure of merit are discussed at the end of this paper. 相似文献
949.
Xiaoxia Wang Hong Zhou Shuangping Yuan Weihao Zheng Ying Jiang Xiujuan Zhuang Hongjun Liu Qinglin Zhang Xiaoli Zhu Xiao Wang Anlian Pan 《Nano Research》2017,10(10):3385-3395
High-performance multiphoton-pumped lasers based on cesium lead halide perovskite nanostructures are promising for nonlinear optics and practical frequency upconversion devices in integrated photonics.However,the performance of such lasers is highly dependent on the quality of the material and cavity,which makes their fabrication challenging.Herein,we demonstrate that cesium lead halide perovskite triangular nanorods fabricated via vapor methods can serve as gain media and effective cavities for multiphoton-pumped lasers.We observed blue-shifts of the lasing modes in the excitation fluence-dependent lasing spectra at increased excitation powers,which fits well with the dynamics of Burstein-Moss shifts caused by the band filling effect.Moreover,efficient multiphoton lasing in CsPbBr3 nanorods can be realized in a wide excitation wavelength range (700-1,400 nm).The dynamics of multiphoton lasing were investigated by time-resolved photoluminescence spectroscopy,which indicated that an electron-hole plasma is responsible for the multiphoton-pumped lasing.This work could lead to new opportunities and applications for cesium lead halide perovskite nanostructures in frequency upconversion lasing devices and optical interconnect systems. 相似文献
950.
Wei Zhai Qing Ai Lina Chen Shiyuan Wei Deping Li Lin Zhang Pengchao Si Jinkui Feng Lijie Ci 《Nano Research》2017,10(12):4274-4283
Silicon is considered an exceptionally promising alternative to the most commonly used material, graphite, as an anode for next-generation lithium-ion batteries, as it has high energy density owing to its high theoretical capacity and abundant storage. Here, microsized walnut-like porous silicon/reduced graphene oxide (P-Si/rGO) core–shell composites are successfully prepared via in situ reduction followed by a dealloying process. The composites show specific capacities of more than 2,100 mAh·g?1 at a current density of 1,000 mA·g?1, 1,600 mAh·g?1 at 2,000 mA·g?1, 1,500 mAh·g?1 at 3,000 mA·g?1, 1,200 mAh·g?1 at 4,000 mA·g?1, and 950 mAh·g?1 at 5,000 mA·g?1, and maintain a value of 1,258 mAh·g?1 after 300 cycles at a current density of 1,000 mA·g?1. Their excellent rate performance and cycling stability can be attributed to the unique structural design: 1) The graphene shell dramatically improves the conductivity and stabilizes the solid–electrolyte interface layers; 2) the inner porous structure supplies sufficient space for silicon expansion; 3) the nanostructure of silicon can prevent the pulverization resulting from volume expansion stress. Notably, this in situ reduction method can be applied as a universal formula to coat graphene on almost all types of metals and alloys of various sizes, shapes, and compositions without adding any reagents to afford energy storage materials, graphene-based catalytic materials, graphene-enhanced composites, etc. 相似文献