全文获取类型
收费全文 | 2651篇 |
免费 | 256篇 |
国内免费 | 825篇 |
专业分类
化学 | 3415篇 |
晶体学 | 49篇 |
力学 | 23篇 |
综合类 | 31篇 |
数学 | 2篇 |
物理学 | 212篇 |
出版年
2024年 | 13篇 |
2023年 | 88篇 |
2022年 | 136篇 |
2021年 | 194篇 |
2020年 | 176篇 |
2019年 | 138篇 |
2018年 | 121篇 |
2017年 | 132篇 |
2016年 | 160篇 |
2015年 | 118篇 |
2014年 | 142篇 |
2013年 | 228篇 |
2012年 | 233篇 |
2011年 | 149篇 |
2010年 | 136篇 |
2009年 | 190篇 |
2008年 | 156篇 |
2007年 | 192篇 |
2006年 | 166篇 |
2005年 | 152篇 |
2004年 | 118篇 |
2003年 | 102篇 |
2002年 | 104篇 |
2001年 | 51篇 |
2000年 | 46篇 |
1999年 | 55篇 |
1998年 | 43篇 |
1997年 | 37篇 |
1996年 | 15篇 |
1995年 | 33篇 |
1994年 | 27篇 |
1993年 | 22篇 |
1992年 | 19篇 |
1991年 | 5篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 6篇 |
1987年 | 5篇 |
1986年 | 7篇 |
1985年 | 1篇 |
1982年 | 2篇 |
1979年 | 1篇 |
排序方式: 共有3732条查询结果,搜索用时 578 毫秒
201.
通过煅烧的方式制得多壁碳纳米管(MWCNT)质量分数为3%的MWCNT/Li1.18Ni0.15Co0.15Mn0.52O2锂离子电池复合正极材料,并测试了复合正极材料在不同服役温度环境下的电化学性能:-20和60℃下服役时,其放电容量分别高达169、303 mAh·g-1,且展示出良好的倍率性能和循环稳定性。结合电化学阻抗测试结果可知,MWCNT均匀附着在层状粒子的表面,有效减少了电解液对电极材料的侵蚀,阻碍了表面膜的生成,同时提高了材料的电子电导率。 相似文献
202.
为了开发较高能量密度的超级电容器,我们通过简单的溶剂热反应合成了一种三维的钴基金属有机框架(MOF)化合物([KCo7(OH)3(ip)6(H2O)4]·12H2O,Co?ip;ip=间苯二甲酸根),并考察了其作为超级电容器电极材料的性能。Co?ip电极显示出高比电容、良好的循环稳定性和优良的倍率性能。在1 mol·L^-1 KOH溶液中,电流密度为1 A·g^-1时,其最大比电容为1660 F·g^-1。在电流密度为2 A·g^-1条件下,循环3000次后,其比电容的保持率为82.7%。优异的超级电容性能可归因于Co?ip具有纳米尺寸颗粒和三维的多孔结构。 相似文献
203.
204.
Manuela Zanetti Devid Maniglio Cristian Fasoli Marco Pola Elisa Borga Claudio Corradi Mauro Dalla Serra Salvatore Iannotta Antonella Motta Tullio Toccoli 《Electroanalysis》2014,26(8):1653-1659
We report the fabrication of a microfluidic apparatus and the realization of a sensors based on PEDOT : PSS, a biocompatible semiconductor polymer used in substitution of standard electrodes for electrophysiological studies and for detection of nanopores in membrane. This gives the possibility to study the mechanisms of ions balance and molecular transport though cell membranes. In particular the apparatus is based on two chambers connected through an aperture in a PTFE sheet where lipid bilayer are formed using Montal‐Mueller method, and the pore‐forming proteins activity is detected by polymeric electrodes. This methodology could be applied to examine different membrane proteins for the purpose of biosensing, drug screening and nanopore technologies. 相似文献
205.
Controllable Release and High‐Efficiency Collection of Hydrogen Peroxide: Application on the Quantitative Investigation of Biomolecule Oxidation Induced by Reactive Oxygen Species
下载免费PDF全文
![点击此处可从《Electroanalysis》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Hydrogen peroxide and hydroxyl radical, both important members of the reactive oxygen species (ROS) family, can cause serious oxidative damages in biological systems. In order to proclaim and prevent oxidation stress, researches on the biomolecule oxidation induced by H2O2 or OH. are in crucial need. However, due to the high reactivity of ROS, traditional methods are difficult to achieve the in situ quantitative investigations on those reactions involving ROS. In this work, using scanning electrochemical microscopy technique (SECM) in a tip generation‐substrate collection mode (TG‐SC), the controllable release and the high‐efficiency collection of electrogenerated H2O2 were achieved. Compared to ex situ fluorescence method, SECM improved the collection efficiency approximately two times larger. Based on it, SECM combined with surface plasmon resonance (SPR) was employed to in situ monitor the protein oxidation (taking Cu12+? MT as a model) induced by H2O2. OH., which was generated from the interaction between H2O2 and Cu12+? MT, can attack the peptide chain and induced the unrepairable protein oxidation damage. The whole process was quantitatively characterized by SPR, and the linear relationship between SPR dip shift and the amounts of released H2O2 was successfully built. Our work proves that the combined SECM‐SPR technique can realize the in situ quantitative determinations of the biomolecule oxidation induced by ROS, which affords an avenue for further elucidation on the mechanisms of oxidation stress in organisms. 相似文献
206.
In the case of disruption of Hcy metabolism, the blood level of Hcy increases and it causes particularly the cardiovascular diseases, cancer, dementia and Parkinson’s disease. Thus, the sensitive analysis of Hcy levels in biological fluids is very important. Hcy analysis was performed herein using very practical and cost‐effective protocol using differential pulse voltammetry and graphite electrode. Detection limit of Hcy was found to be 1.21 µM in the linear range from 2 µM to 20 µM. The electrochemical Hcy detection in artificial urine medium was also successfully performed even in the presence of L ‐Cysteine, L ‐Methionine and Glutathione. 相似文献
207.
采用阳极氧化法和脉冲电沉积制备出β-PbO2改性TiO2纳米管(β-PbO2/TiO2-NTs)电极,通过扫描电子显微镜(SEM)、X射线衍射(XRD)和X射线光电子能谱(XPS)等技术手段对制备的β-PbO2/TiO2-NTs电极的表面形貌和结构进行了表征。结果表明,该方法成功地将β-PbO2纳米颗粒分散在TiO2纳米管中,通过电催化降解苯酚评价了β-PbO2/TiO2-NTs电极的电催化活性,实验结果表明,在TiO2-NTs中电沉积β-PbO2提高了电极的电催化活性,对苯酚的降解达到83%。 相似文献
208.
209.
利用电化学湿法印章技术在氧化铟锡(ITO)导电玻璃上制备AuPd合金和Au的双组分阵列图案. 采用具有微浮雕图案的琼脂糖印章存储足够多的溶液,并通过控制电沉积的时间来控制图案厚度. 应用场发射扫描电子显微镜(FE-SEM),X射线能谱分析(EDX)和原子力显微镜(AFM)分别对ITO表面上的AuPd合金和Au的形貌和组分进行表征,并通过循环伏安(CV)技术和扫描电化学显微镜(SECM)研究比较了Au和AuPd合金的催化活性. 利用扫描电化学显微镜(SECM)的针尖产生-基底收集(TG-SC)模式和氧化还原竞争(RC)模式,发现Au电极对二茂铁甲醇氧化物(FcMeOH+)电催化还原能力高于AuPd合金电极,而在AuPd合金上催化还原H2O2的能力显著高于Au. 相似文献
210.
Scanning Droplet Cell for Chemoselective Patterning through Local Electroactivation of Protected Quinone Monolayers
下载免费PDF全文
![点击此处可从《Chemphyschem》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jan Clausmeyer Dr. Jörg Henig Prof. Dr. Wolfgang Schuhmann Dr. Nicolas Plumeré 《Chemphyschem》2014,15(1):151-156
A reagentless strategy for template‐free patterning of uniformly inert surfaces is suggested. A layer of p‐hydroquinone (HQ) protected by the tert‐butyldimethylsilyl (TBDMS) group is electrografted onto glassy carbon electrodes. Chemoselective activation is performed through electrochemically controlled cleavage of the TBDMS group, which yields the redox‐active surface‐confined quinone moieties. The latter are shown to undergo electrochemically induced Michael addition, which serves for subsequent functionalization of the electrode surface. Patterning of the TBDMS–quinone‐modified surface is accomplished by using selective localized cleavage of the protecting group. State‐of‐the‐art direct‐mode scanning electrochemical microscopy (SECM) patterning fails to yield the anticipated interfacial reaction; however, the electrochemical scanning droplet cell (SDC) is capable of conducting the localized chemoselective reaction. In a small area, dictated by the dimensions of the droplet, electrochemically induced cleavage of the protecting group can be performed locally to give rise to arrays of active quinone spots. Upon deprotection, the redox signals, attributed to the hydroquinone/benzoquinone couple, provide the first direct evidence for chemoselective electrochemical patterning of sensitive functionalities. Subsequent SECM studies of the resulting modified areas demonstrate spatial control of the proposed patterning technique. 相似文献