全文获取类型
收费全文 | 3666篇 |
免费 | 219篇 |
国内免费 | 152篇 |
专业分类
电工技术 | 153篇 |
综合类 | 102篇 |
化学工业 | 1248篇 |
金属工艺 | 272篇 |
机械仪表 | 104篇 |
建筑科学 | 82篇 |
矿业工程 | 37篇 |
能源动力 | 538篇 |
轻工业 | 101篇 |
水利工程 | 15篇 |
石油天然气 | 183篇 |
武器工业 | 16篇 |
无线电 | 341篇 |
一般工业技术 | 376篇 |
冶金工业 | 156篇 |
原子能技术 | 105篇 |
自动化技术 | 208篇 |
出版年
2024年 | 3篇 |
2023年 | 56篇 |
2022年 | 74篇 |
2021年 | 111篇 |
2020年 | 110篇 |
2019年 | 111篇 |
2018年 | 96篇 |
2017年 | 121篇 |
2016年 | 113篇 |
2015年 | 100篇 |
2014年 | 185篇 |
2013年 | 297篇 |
2012年 | 265篇 |
2011年 | 282篇 |
2010年 | 239篇 |
2009年 | 236篇 |
2008年 | 208篇 |
2007年 | 275篇 |
2006年 | 198篇 |
2005年 | 153篇 |
2004年 | 101篇 |
2003年 | 98篇 |
2002年 | 93篇 |
2001年 | 76篇 |
2000年 | 70篇 |
1999年 | 50篇 |
1998年 | 57篇 |
1997年 | 30篇 |
1996年 | 48篇 |
1995年 | 25篇 |
1994年 | 35篇 |
1993年 | 31篇 |
1992年 | 21篇 |
1991年 | 21篇 |
1990年 | 14篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 3篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 2篇 |
1983年 | 5篇 |
1982年 | 1篇 |
1979年 | 1篇 |
排序方式: 共有4037条查询结果,搜索用时 15 毫秒
91.
M. I. Viseu C. A. Nieto de Castro S. M. B. Costa 《International Journal of Thermophysics》1991,12(2):323-331
Diffusion coefficients of the electron acceptor dye tetrazolium blue were measured by the Taylor dispersion method, with an accuracy better than 4%, in two solvents: (i) a homogeneous one-aqueous phosphate buffer, 0.1 M, pH=7.0 (medium I); and (ii) a heterogeneous one-nonionic micelles of Triton X-100, 2.0 mM (where M stands for mol·dm–3), in the same aqueous phosphate buffer (medium II). The values obtained were D
12
I
=3.64×10–10m2·s–1 and D
12
II
=3.01×10–10m2·s–1·D
12
II
has the meaning of a macroscopird or average diffusion coefficient, in which the partition coefficient of tetrazolium blue between micelles and water, as well as the diffusion coefficients of this dye and of the micelles in the aqueous phase, are involved. 相似文献
92.
Felix Schmutzler Christopher Zschiesche Juliane Titus David Poppitz Jens Freiding Rainer Rakoczy Andreas Reitzmann Roger Gläser 《化学,工程师,技术》2021,93(6):981-989
The hydroisomerization of two long-chain n-alkane mixtures was investigated over bifunctional Pt/H-ZSM-5 catalysts before and after dealumination of preshaped zeolite/binder pellets. The hydroisomerization over the dealuminated catalysts leads to more isomers and less cracking products. Consequently, higher ratios of multi- to mono-branched isomerization products are formed as expected for large- rather than medium-pore zeolites. This indicates a higher availability of space in the vicinity of the active sites and provides an attractive route to make medium-pore zeolites suitable for upgrading higher boiling hydrocarbon feeds. 相似文献
93.
电催化剂是质子交换膜燃料电池中非常重要的关键材料,文中详细地介绍了大连化学物理研究所燃料电池工程中心所研制的高分散度Pt/C催化剂的制备和表征结果,采用这种Pt/C催化剂组装了5kW的电池组,电池组良好的性能验证了催化剂的高活性,为了提高催化剂的利用率,文中研究了催化剂分散度和电池性能的关系,研究表明阳极侧催化剂分散度越高对提高电池的性能越有利,而在阴极侧Pt分散度的增加对电池的性能影响不大,这是因为反应界面上Pt分散度增加后降低了氧还原反应的比活性。 相似文献
94.
95.
AerMet100超高强度钢热变形行为 总被引:3,自引:0,他引:3
在热模拟机上对AerMet100超高强度钢进行了恒温和恒应变速率的热压缩实验,温度范围是900℃~1100℃,应变速率范围是0.01s-1~10s-1。实测了高温下应力-应变关系曲线,观察了变形后的显微组织,计算了材料的激活能,并建立了峰值应力与变形温度和应变速率的关系。结果表明,材料的流动应力随着变形温度的升高而降低,随应变速率的增大而增大;材料在不同变形条件下其软化机制分别受动态回复和动态再结晶控制;在实验条件范围内,AerMet100超高强度钢的再结晶温度在1000℃~1050℃之间,材料的热变形激活能为261.2kJ/mol。 相似文献
96.
郁琰 《自动化技术与应用》2010,29(8):90-92
本文在分析100KHZ高频逆变电源电路拓扑的基础上,对100KHZ的高频逆变电源进行了参数设计,并在SIMULINK环境下对100KHZ高频逆变电源系统及数字锁相进行了仿真,给出了逆变器输出电压与输出电流的仿真波形,验证了ZCS软开关工作模式。 相似文献
97.
98.
Tuning Surface Structure and Strain in Pd–Pt Core–Shell Nanocrystals for Enhanced Electrocatalytic Oxygen Reduction
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
99.
Immobilization of Pt Nanoparticles via Rapid and Reusable Electropolymerization of Dopamine on TiO2 Nanotube Arrays for Reversible SERS Substrates and Nonenzymatic Glucose Sensors
下载免费PDF全文
![点击此处可从《Small (Weinheim an der Bergstrasse, Germany)》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jingsheng Cai Jianying Huang Mingzheng Ge James Iocozzia Zhiqun Lin Ke‐Qin Zhang Yuekun Lai 《Small (Weinheim an der Bergstrasse, Germany)》2017,13(19)
Inspired by mussel‐adhesion phenomena in nature, polydopamine (PDA) coatings are a promising route to multifunctional platforms for decorating various materials. The typical self‐polymerization process of dopamine is time‐consuming and the coatings of PDA are not reusable. Herein, a reusable and time‐saving strategy for the electrochemical polymerization of dopamine (EPD) is reported. The PDA layer is deposited on vertically aligned TiO2 nanotube arrays (NTAs). Owing to the abundant catechol and amine groups in the PDA layer, uniform Pt nanoparticles (NPs) are deposited onto the TiO2 NTAs and can effectively prevent the recombination of electron–hole pairs generated from photo‐electrocatalysis and transfer the captured electrons to participate in the photo‐electrocatalytic reaction process. Compared with pristine TiO2 NTAs, the as‐prepared Pt@TiO2 NTA composites exhibit surface‐enhanced Raman scattering sensitivity for detecting rhodamine 6G and display excellent UV‐assisted self‐cleaning ability, and also show promise as a nonenzymatic glucose biosensor. Furthermore, the mussel‐inspired electropolymerization strategy and the fast EPD‐reduced nanoparticle decorating process presented herein can be readily extended to various functional substrates, such as conductive glass, metallic oxides, and semiconductors. It is the adaptation of the established PDA system for a selective, robust, and generalizable sensing system that is the emphasis of this work. 相似文献
100.
Yueyue Wang Feifei Qin Junfeng Lu Jitao Li Zhu Zhu Qiuxiang Zhu Ye Zhu Zengliang Shi Chunxiang Xu 《Nano Research》2017,10(10):3447-3456
It is essential to develop a single mode operation and improve the performance of lasing in order to ensure practical applicability of microlasers and nanolasers.In this paper,two hexagonal microteeth with varied nanoscaled air-gaps of a ZnO microcomb are used to construct coupled whispering-gallery cavities.This is done to achieve a stable single mode lasing based on Vernier effect without requiring any complicated or sophisticated manipulation to achieve positioning with nanoscale precision.Optical gain and the corresponding ultraviolet lasing performance were improved greatly through coupling with localized surface plasmons of Pt nanoparticles.The ZnO/Pt hybrid microcavities achieved a seven-fold enhancement of intensity of single mode lasing with higher sidemode suppression ratio and lower threshold.The mechanism that led to this enhancement has been described in detail. 相似文献