全文获取类型
收费全文 | 3575篇 |
免费 | 136篇 |
国内免费 | 650篇 |
专业分类
化学 | 3844篇 |
晶体学 | 22篇 |
力学 | 12篇 |
综合类 | 1篇 |
数学 | 1篇 |
物理学 | 481篇 |
出版年
2024年 | 11篇 |
2023年 | 142篇 |
2022年 | 138篇 |
2021年 | 153篇 |
2020年 | 174篇 |
2019年 | 112篇 |
2018年 | 76篇 |
2017年 | 131篇 |
2016年 | 163篇 |
2015年 | 166篇 |
2014年 | 184篇 |
2013年 | 160篇 |
2012年 | 275篇 |
2011年 | 225篇 |
2010年 | 214篇 |
2009年 | 267篇 |
2008年 | 258篇 |
2007年 | 243篇 |
2006年 | 219篇 |
2005年 | 199篇 |
2004年 | 184篇 |
2003年 | 122篇 |
2002年 | 83篇 |
2001年 | 101篇 |
2000年 | 46篇 |
1999年 | 41篇 |
1998年 | 45篇 |
1997年 | 36篇 |
1996年 | 23篇 |
1995年 | 30篇 |
1994年 | 13篇 |
1993年 | 21篇 |
1992年 | 15篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 10篇 |
1988年 | 17篇 |
1987年 | 12篇 |
1986年 | 3篇 |
1985年 | 6篇 |
1984年 | 7篇 |
1983年 | 1篇 |
1982年 | 6篇 |
1979年 | 1篇 |
排序方式: 共有4361条查询结果,搜索用时 15 毫秒
991.
Nanostructured Base Electrochemical Sensor for Simultaneous Quantification and Voltammetric Studies of Levodopa and Carbidopa in Pharmaceutical Products and Biological Samples 下载免费PDF全文
A novel carbon paste electrode modified with carbon nanotubes and 5‐amino‐2′‐ethyl‐biphenyl‐2‐ol (5AEB) was fabricated. The electrochemical study of the modified electrode, as well as its efficiency for electrocatalytic oxidation of levodopa (LD) and carbidopa (CD), is described. Cyclic voltammetry (CV) was used to investigate the redox properties of this modified electrode at various scan rates. The apparent charge transfer rate constant, ks, and transfer coefficient, a, for electron transfer between 5AEB and CPE were calculated as 17.3 s?1 and 0.5, respectively. Square wave voltammetry (SWV) exhibits a linear dynamic range from 2.5×10?7 to 2.0×10?4 M and a detection limit of 9.0×10?8 M for LD. 相似文献
992.
添加剂对染料敏化太阳电池电解质性能的影响 总被引:1,自引:0,他引:1
以N-甲基咪唑、苯并咪唑、叔丁基吡啶和离子液体1-甲基-3-乙基咪唑三氟乙酸盐(EMITA)作为染料敏化太阳电池(DSCs)电解质溶液中的添加剂, 使用超微电极通过循环伏安法研究其对液体电解质中I-3和I-氧化还原行为的影响, 通过电化学阻抗谱研究了上述四种添加剂对Pt电极电解质界面的影响. 结果表明, 添加剂EMITA的加入使I-3在电解质中的扩散系数减小, Pt电极电解质界面上的界面传输电阻Rct增大, 电解质的电阻降低; 光伏性能测试表明, EMITA的添加提高了DSCs的开路电压和填充因子, 其DSCs的光电转换效率达到了5.72%. 相似文献
993.
Abolanle S. Adekunle Kenneth I. Ozoemena 《Journal of Solid State Electrochemistry》2008,12(10):1325-1336
Electrochemistry of edge-plane pyrolytic graphite electrodes (EPPGEs) modified with Aldrich single-walled carbon nanotubes
(SWCNTs) electro-decorated with metal (Ni, Fe and Co) and their oxides have been studied. The morphology and identity of the
metallic dispersions were examined by scanning electron microscopy and energy-dispersive spectroscopy. We show that SWCNTs
serve as efficient conducting carbon material for electronic communication between metal films and the underlying carbon electrode.
By using cyclic voltammetry and electrochemical impedance spectroscopy (EIS) techniques, it is proved that both EPPGE-SWCNT-Ni
and EPPGE-SWCNT-Fe exhibit comparable electrochemical response in buffered aqueous solution (pH 7.0) and towards electro-oxidation
of hydrazine in Na2SO4 solution. The impedance spectra of these SWCNT-metal hybrids were complicated and follow electrical equivalent circuit model
typical of adsorption-controlled charge transfer kinetics. Hydrazine impedance spectra exhibited inductive loop, characteristic
of Faradaic current being governed by the occupation of an intermediate state. On the other hand, the EIS data obtained in
a simple redox probe, [Fe(CN)6]3−/[Fe(CN)6]4−, showed that EPPGE-SWCNT and EPPGE-SWCNT-Ni followed electrical equivalent circuit models typical of partial charge transfer
or adsorption-controlled kinetics with some resemblance to the behaviour of electrolyte–insulator–semiconductor sensors. 相似文献
994.
Dan Han Mao‐Sheng Cao Na Li Dong‐Mei She Wei‐Li Song Haosen Chen Shuqiang Jiao Daining Fang 《中国化学》2021,39(1):157-164
Graphitic materials with intercalated sites are considered as the mostly used positive electrode materials in nonaqueous Al batteries. Unlike the small‐size cations, the intercalation/de‐intercalation of large‐size anions into/out of graphite would induce large volume expansion and micro‐structure reconfiguration, leading to unexpected coulombic efficiency in the full cells (<95% within initial several cycles). For understanding the irreversible processes induced by anion intercalation/de‐intercalation (AlCl4–), here the kinetics of first two cycles for the Al‐graphite batteries have been systematically studied. To study kinetics behaviors at representative states, a combined method upon galvanostatic intermittent titration technique and electrochemical impedance spectroscopy has been carried out. The achieved diffusion coefficients of the positive electrodes assembled with different graphite sizes suggest that size effect also plays a critical role in determining the electrochemical kinetics in the mass transport in both electrolyte and graphitic layers as well as in interface reaction. The morphologies and micro‐structures of the post‐cycled graphite electrodes have been also experimentally studied, which also well supports the irreversible intercalation/de‐intercalation behaviors in graphite electrodes. The results offer a significant platform to well understand the essential factors in tailoring coulombic efficiency from a kinetic view, which would be helpful in promoting the graphite electrodes in Al batteries. 相似文献
995.
Ahmad Alawad Laure Latapie David Evrard Pierre Gros Georges Istamboulie Thierry Noguer Carole Calas-Blanchard 《Electroanalysis》2021,33(2):292-295
Scanning electrochemical microscopy (SECM) is discussed as a versatile tool to provide a unique approach of localized electrochemical information in the context of biosensing research. The step-by-step immobilization of DNA aptamer with intrinsic redox activity on screen-printed carbon electrode (SPCE) was successfully monitored using SECM imaging tool. Control experiments were performed with a non-electroactive aptamer. After immobilization of these aptamers, SECM images showed the repartition of the electroactive anti-tetracycline aptamer when comparing with images produced for control and for all modification steps of SPCE. The possibility of tetracycline detection was also proved by causing a decrease in recorded current. 相似文献
996.
Jin Yong Park Dong-Wook Lee Jonggi Hong Seong Jun Kim Jung-Woo Ok Jang-Hee Yoon Mi-Sook Won 《Electroanalysis》2021,33(7):1715-1720
The O and N gas ions (O3+, O+, N2+, and N4+) were implanted on the glassy carbon surface employing the electron cyclotron resonance ion source, which were characterized using electrochemical and surface analysis methods. The modified electrode was examined for the catalytic oxidation of bioorganic molecules including dopamine, where the O+ ion implanted GC revealed the best catalytic performance. The XPS and Raman results represented that the ion implantation made enrichment in graphite nanocrystalline structure with edge plane, showing the enhanced electrochemical activity. It showed excellent performance for dopamine detection without significant interferences between 50.0 nM and 400.0 μM with the detection limit of 10.0±2.5 nM (95 % confidence level). The reliability of proposed electrode was evaluated by the real urine sample analysis. 相似文献
997.
以铂电极支撑的磷脂双层膜(Supported Bilayer Lipid Membrane,s-BLM)作为生物膜的模型,以Fe(CN)36-和Fe(CN)64-为探针分子,利用循环伏安法(CV)和交流阻抗谱(EIS)研究两性表面活性剂十二烷基磺基甜菜碱(Dodecyl Sulfobetaine,DSB)对s-BLM相互作用。结果显示,DSB可以嵌入到s-BLM的疏水区,容易使其表面分子的排列发生变化,产生缺陷或孔洞,探针分子Fe(CN)63-和Fe(CN)64-可以通过这些微孔接近电极,产生氧化还原响应。并且作用时间、DSB的浓度以及胆固醇的存在与否对二者的相互作用有直接影响。此外作用后的双层膜在0.1mol/LKCl溶液中能够自我修复,这表明DSB与s-BLM的相互作用是可逆的。 相似文献
998.
The electrochemical biosensor properties of the molecular devices based on solid supported bilayer lipid membranes were investigated. The results showed that the system embedded with antihistaminic agent had strong response for the histamine. The response currents for the histamine will rise following the increasing concentrations of the histamine,as a result of the special opposing effect between histamine and antihistamine. Near the normal physiological condition(pH=7. 5),a good linearity occurred for the current response against histamine concentration ranging from 3. 0 to 60. 0 μg / L,and the relation coefficient R is 0. 9878. All the experiments mentioned above showed good sensitivity,selectivity and stability. This system can measure the concentration of histamine under -200 mV by voltammetry and be expected to form the electrochemical biosensor with high stability and low detection limit. 相似文献
999.
1000.