全文获取类型
收费全文 | 4206篇 |
免费 | 468篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 42篇 |
综合类 | 1篇 |
化学工业 | 1134篇 |
金属工艺 | 111篇 |
机械仪表 | 218篇 |
建筑科学 | 105篇 |
矿业工程 | 1篇 |
能源动力 | 176篇 |
轻工业 | 350篇 |
水利工程 | 10篇 |
石油天然气 | 2篇 |
武器工业 | 2篇 |
无线电 | 936篇 |
一般工业技术 | 1039篇 |
冶金工业 | 173篇 |
原子能技术 | 28篇 |
自动化技术 | 356篇 |
出版年
2024年 | 2篇 |
2023年 | 62篇 |
2022年 | 56篇 |
2021年 | 140篇 |
2020年 | 119篇 |
2019年 | 134篇 |
2018年 | 176篇 |
2017年 | 151篇 |
2016年 | 172篇 |
2015年 | 149篇 |
2014年 | 228篇 |
2013年 | 298篇 |
2012年 | 339篇 |
2011年 | 351篇 |
2010年 | 268篇 |
2009年 | 253篇 |
2008年 | 283篇 |
2007年 | 199篇 |
2006年 | 155篇 |
2005年 | 135篇 |
2004年 | 134篇 |
2003年 | 122篇 |
2002年 | 110篇 |
2001年 | 101篇 |
2000年 | 83篇 |
1999年 | 82篇 |
1998年 | 101篇 |
1997年 | 60篇 |
1996年 | 41篇 |
1995年 | 43篇 |
1994年 | 25篇 |
1993年 | 16篇 |
1992年 | 11篇 |
1991年 | 6篇 |
1990年 | 14篇 |
1989年 | 11篇 |
1988年 | 4篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 9篇 |
1984年 | 6篇 |
1981年 | 4篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1976年 | 3篇 |
1975年 | 1篇 |
1973年 | 2篇 |
1969年 | 1篇 |
1968年 | 1篇 |
1967年 | 2篇 |
排序方式: 共有4684条查询结果,搜索用时 15 毫秒
91.
Rational Design and Synthesis of Extremely Efficient Macroporous CoSe2–CNT Composite Microspheres for Hydrogen Evolution Reaction 下载免费PDF全文
Jin Koo Kim Gi Dae Park Jung Hyun Kim Seung‐Keun Park Yun Chan Kang 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(27)
Uniquely structured CoSe2–carbon nanotube (CNT) composite microspheres with optimized morphology for the hydrogen‐evolution reaction (HER) are prepared by spray pyrolysis and subsequent selenization. The ultrafine CoSe2 nanocrystals uniformly decorate the entire macroporous CNT backbone in CoSe2–CNT composite microspheres. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe2 by improving the electrical conductivity and minimizing the growth of CoSe2 nanocrystals during the synthesis process. In addition, the macroporous structure resulting from the CNT backbone improves the electrocatalytic activity of the CoSe2–CNT microspheres by increasing the removal rate of generated H2 and minimizing the polarization of the electrode during HER. The CoSe2–CNT composite microspheres demonstrate excellent catalytic activity for HER in an acidic medium (10 mA cm?2 at an overpotential of ≈174 mV). The bare CoSe2 powders exhibit moderate HER activity, with an overpotential of 226 mV at 10 mA cm?2. The Tafel slopes for the CoSe2–CNT composite and bare CoSe2 powders are 37.8 and 58.9 mV dec?1, respectively. The CoSe2–CNT composite microspheres have a slightly larger Tafel slope than that of commercial carbon‐supported platinum nanoparticles, which is 30.2 mV dec–1. 相似文献
92.
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
93.
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
94.
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
95.
96.
Seung‐Hwan Boo Jin‐Gyun Kim Phill‐Seung Lee 《International journal for numerical methods in engineering》2016,106(11):927-950
In this study, we propose an effective method to estimate the reliability of finite element models reduced by the automated multi‐level substructuring (AMLS) method. The proposed error estimation method can accurately predict relative eigenvalue errors in reduced finite element models. A new, enhanced transformation matrix for the AMLS method is derived from the original transformation matrix by properly considering the contribution of residual substructural modes. The enhanced transformation matrix is an important prerequisite to develop the error estimation method. Adopting the basic concept of the error estimation method recently developed for the Craig–Bampton method, an error estimation method is developed for the AMLS method. Through various numerical examples, we demonstrate the accuracy of the proposed error estimation method and explore its computational efficiency. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
97.
98.
A High‐Performance WSe2/h‐BN Photodetector using a Triphenylphosphine (PPh3)‐Based n‐Doping Technique 下载免费PDF全文
99.
100.