全文获取类型
收费全文 | 46787篇 |
免费 | 3333篇 |
国内免费 | 905篇 |
专业分类
电工技术 | 1628篇 |
技术理论 | 1篇 |
综合类 | 1393篇 |
化学工业 | 9307篇 |
金属工艺 | 2193篇 |
机械仪表 | 2630篇 |
建筑科学 | 2282篇 |
矿业工程 | 576篇 |
能源动力 | 1752篇 |
轻工业 | 3547篇 |
水利工程 | 430篇 |
石油天然气 | 1343篇 |
武器工业 | 118篇 |
无线电 | 6721篇 |
一般工业技术 | 7911篇 |
冶金工业 | 2957篇 |
原子能技术 | 617篇 |
自动化技术 | 5619篇 |
出版年
2024年 | 73篇 |
2023年 | 664篇 |
2022年 | 946篇 |
2021年 | 1696篇 |
2020年 | 1185篇 |
2019年 | 1160篇 |
2018年 | 1394篇 |
2017年 | 1458篇 |
2016年 | 1509篇 |
2015年 | 1525篇 |
2014年 | 2176篇 |
2013年 | 2977篇 |
2012年 | 3064篇 |
2011年 | 3535篇 |
2010年 | 2711篇 |
2009年 | 2797篇 |
2008年 | 2571篇 |
2007年 | 2190篇 |
2006年 | 2170篇 |
2005年 | 1880篇 |
2004年 | 1486篇 |
2003年 | 1355篇 |
2002年 | 1361篇 |
2001年 | 1063篇 |
2000年 | 963篇 |
1999年 | 1029篇 |
1998年 | 1286篇 |
1997年 | 886篇 |
1996年 | 840篇 |
1995年 | 604篇 |
1994年 | 447篇 |
1993年 | 340篇 |
1992年 | 285篇 |
1991年 | 216篇 |
1990年 | 166篇 |
1989年 | 160篇 |
1988年 | 161篇 |
1987年 | 111篇 |
1986年 | 94篇 |
1985年 | 64篇 |
1984年 | 65篇 |
1983年 | 41篇 |
1982年 | 56篇 |
1981年 | 38篇 |
1980年 | 38篇 |
1979年 | 28篇 |
1977年 | 26篇 |
1976年 | 42篇 |
1975年 | 21篇 |
1974年 | 16篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
How Effective is Plasmonic Enhancement of Colloidal Quantum Dots for Color‐Conversion Light‐Emitting Devices? 下载免费PDF全文
Hyun Chul Park Isnaeni Suhyun Gong Yong‐Hoon Cho 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(48)
Enhancing the fluorescence intensity of colloidal quantum dots (QDs) in case of color‐conversion type QD light‐emitting devices (LEDs) is very significant due to the large loss of QDs and their quantum yields during fabrication processes, such as patterning and spin‐coating, and can therefore improve cost‐effectiveness. Understanding the enhancement process is crucial for the design of metallic nanostructure substrates for enhancing the fluorescence of colloidal QDs. In this work, improved color conversion of colloidal green and red QDs coupled with aluminum (Al) and silver (Ag) nanodisk (ND) arrays designed by in‐depth systematic finite‐difference time domain simulations of excitation, spontaneous emission, and quantum efficiency enhancement is reported. Calculated results of the overall photoluminescence enhancement factor in the substrate of 500 × 500 µm2 size are 2.37‐fold and 2.82‐fold for Al ND‐green QD and Ag ND‐red QD structures, respectively. Experimental results are in good agreement, showing 2.26‐fold and 2.66‐fold enhancements for Al ND and Ag ND structures. Possible uses of plasmonics in cases such as white LED and total color conversion for possible display applications are discussed. The theoretical treatments and experiments shown in this work are a proof of principle for future studies of plasmonic enhancement of various light‐emitting materials. 相似文献
992.
Designing Metallic and Insulating Nanocrystal Heterostructures to Fabricate Highly Sensitive and Solution Processed Strain Gauges for Wearable Sensors 下载免费PDF全文
Woo Seok Lee Seung‐Wook Lee Hyungmok Joh Mingi Seong Haneun Kim Min Su Kang Ki‐Hyun Cho Yun‐Mo Sung Soong Ju Oh 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
All‐solution processed, high‐performance wearable strain sensors are demonstrated using heterostructure nanocrystal (NC) solids. By incorporating insulating artificial atoms of CdSe quantum dot NCs into metallic artificial atoms of Au NC thin film matrix, metal–insulator heterostructures are designed. This hybrid structure results in a shift close to the percolation threshold, modifying the charge transport mechanism and enhancing sensitivity in accordance with the site percolation theory. The number of electrical pathways is also manipulated by creating nanocracks to further increase its sensitivity, inspired from the bond percolation theory. The combination of the two strategies achieves gauge factor up to 5045, the highest sensitivity recorded among NC‐based strain gauges. These strain sensors show high reliability, durability, frequency stability, and negligible hysteresis. The fundamental charge transport behavior of these NC solids is investigated and the combined site and bond percolation theory is developed to illuminate the origin of their enhanced sensitivity. Finally, all NC‐based and solution‐processed strain gauge sensor arrays are fabricated, which effectively measure the motion of each finger joint, the pulse of heart rate, and the movement of vocal cords of human. This work provides a pathway for designing low‐cost and high‐performance electronic skin or wearable devices. 相似文献
993.
994.
995.
Solar Cells: Multidimensional Anodized Titanium Foam Photoelectrode for Efficient Utilization of Photons in Mesoscopic Solar Cells (Small 34/2017) 下载免费PDF全文
996.
Carbon Nanodot‐Sensitized Modulation of Alzheimer's β‐Amyloid Self‐Assembly,Disassembly, and Toxicity 下载免费PDF全文
You Jung Chung Kayoung Kim Byung Il Lee Chan Beum Park 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(34)
The self‐assembly of amyloidogenic peptides into β‐sheet‐rich aggregates is a general feature of many neurodegenerative diseases, including Alzheimer's disease, which signifies the need for the effective attenuation of amyloid aggregation toward alleviating amyloid‐associated neurotoxicity. This study reports that photoluminescent carbon nanodots (CDs) can effectively suppress Alzheimer's β‐amyloid (Aβ) self‐assembly and function as a β‐sheet breaker disintegrating preformed Aβ aggregates. This study synthesizes CDs using ammonium citrate through one‐pot hydrothermal treatment and passivates their surface with branched polyethylenimine (bPEI). The bPEI‐coated CDs (bPEI@CDs) exhibit hydrophilic and cationic surface characteristics, which interact with the negatively charged residues of Aβ peptides, suppressing the aggregation of Aβ peptides. Under light illumination, bPEI@CDs display a more pronounced effect on Aβ aggregation and on the dissociation of β‐sheet‐rich assemblies through the generation of reactive oxygen species from photoactivated bPEI@CDs. The light‐triggered attenuation effect of Aβ aggregation using a series of experiments, including photochemical and microscopic analysis, is verified. Furthermore, the cell viability test confirms the ability of photoactivated bPEI@CDs for the suppression of Aβ‐mediated cytotoxicity, indicating bPEI@CDs' potency as an effective anti‐Aβ neurotoxin agent. 相似文献
997.
Microsphere‐Assisted Robust Epidermal Strain Gauge for Static and Dynamic Gesture Recognition 下载免费PDF全文
Zongming Su Haotian Chen Yu Song Xiaoliang Cheng Xuexian Chen Hang Guo Liming Miao Haixia Zhang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(47)
A novel and robust epidermal strain gauge by using 3D microsphere arrays to immobilize, connect, and protect a multiwalled carbon nanotubes (MWNTs) pathway is presented. During the solvent deposition process, MWNTs sedimentate, self‐assemble, and wrap onto surface of polystyrene (PS) microspheres to construct conductive networks, which further obtain excellent stretchability of 100% by combining with commercially used elastomer. Benefiting from its 3D conductive pathway defined by microspheres, immobilized MWNT (I‐MWNT) network can be directly used in practical occasions without further packaging and is proved by tape tests to be capable of defend mechanical damage effectively from external environment. By parameter optimization, the strain sensor with 3 µm PS spheres obtains stable resistive responses for more than 1000 times, and maintains its gauge factor (GF) of 1.35. This thin‐film conductive membrane built by this effective construction method can be easily attached onto fingers of both robot and human, and is demonstrated in sensitive epidermal strain sensing and recognizing different hand gestures effectively, in static and dynamic modes, respectively. 相似文献
998.
DNA Imaging: DNA Binding Peptide Directed Synthesis of Continuous DNA Nanowires for Analysis of Large DNA Molecules by Scanning Electron Microscope (Small 2/2017) 下载免费PDF全文
999.
Dominance of Plasmonic Resonant Energy Transfer over Direct Electron Transfer in Substantially Enhanced Water Oxidation Activity of BiVO4 by Shape‐Controlled Au Nanoparticles 下载免费PDF全文
Mi Gyoung Lee Cheon Woo Moon Hoonkee Park Woonbae Sohn Sung Bum Kang Sanghan Lee Kyoung Jin Choi Ho Won Jang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(37)
The performance of plasmonic Au nanostructure/metal oxide heterointerface shows great promise in enhancing photoactivity, due to its ability to confine light to the small volume inside the semiconductor and modify the interfacial electronic band structure. While the shape control of Au nanoparticles (NPs) is crucial for moderate bandgap semiconductors, because plasmonic resonance by interband excitations overlaps above the absorption edge of semiconductors, its critical role in water splitting is still not fully understood. Here, first, the plasmonic effects of shape‐controlled Au NPs on bismuth vanadate (BiVO4) are studied, and a largely enhanced photoactivity of BiVO4 is reported by introducing the octahedral Au NPs. The octahedral Au NP/BiVO4 achieves 2.4 mA cm?2 at the 1.23 V versus reversible hydrogen electrode, which is the threefold enhancement compared to BiVO4. It is the highest value among the previously reported plasmonic Au NPs/BiVO4. Improved photoactivity is attributed to the localized surface plasmon resonance; direct electron transfer (DET), plasmonic resonant energy transfer (PRET). The PRET can be stressed over DET when considering the moderate bandgap semiconductor. Enhanced water oxidation induced by the shape‐controlled Au NPs is applicable to moderate semiconductors, and shows a systematic study to explore new efficient plasmonic solar water splitting cells. 相似文献
1000.
Ji Chan Park Shin Wook Kang Jeong-Chul Kim Jae In Kwon Sanha Jang Geun Bae Rhim Mijong Kim Dong Hyun Chun Ho-Tae Lee Heon Jung Hyunjoon Song Jung-II Yang 《Nano Research》2017,(3):1044-1055
A cobalt-silica hybrid nanocatalyst bearing small cobalt particles of diameter ~5 nm was prepared through a hydrothermal reaction and hydrogen reduction.The resulting material showed very high CO conversion (>82%) and high hydrocarbon productivity (~1.0 gHc·g-1cat,·h-11) with high activity (~8.5 x 10-5 molco·g-1Co·S-1) in the Fischer-Tropsch synthesis reaction. 相似文献