全文获取类型
收费全文 | 5055篇 |
免费 | 580篇 |
国内免费 | 508篇 |
专业分类
化学 | 3314篇 |
晶体学 | 22篇 |
力学 | 231篇 |
综合类 | 45篇 |
数学 | 69篇 |
物理学 | 2462篇 |
出版年
2024年 | 5篇 |
2023年 | 73篇 |
2022年 | 159篇 |
2021年 | 197篇 |
2020年 | 236篇 |
2019年 | 170篇 |
2018年 | 141篇 |
2017年 | 258篇 |
2016年 | 306篇 |
2015年 | 272篇 |
2014年 | 353篇 |
2013年 | 360篇 |
2012年 | 407篇 |
2011年 | 319篇 |
2010年 | 249篇 |
2009年 | 296篇 |
2008年 | 303篇 |
2007年 | 308篇 |
2006年 | 249篇 |
2005年 | 219篇 |
2004年 | 227篇 |
2003年 | 165篇 |
2002年 | 156篇 |
2001年 | 93篇 |
2000年 | 89篇 |
1999年 | 92篇 |
1998年 | 90篇 |
1997年 | 86篇 |
1996年 | 48篇 |
1995年 | 47篇 |
1994年 | 36篇 |
1993年 | 35篇 |
1992年 | 21篇 |
1991年 | 23篇 |
1990年 | 23篇 |
1989年 | 11篇 |
1988年 | 8篇 |
1987年 | 7篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
排序方式: 共有6143条查询结果,搜索用时 15 毫秒
81.
Ying Zhang Yong-Guang Gao You-Di Shi Lian-Qian Tan Jessica S. Yue Zhong-Lin Lu 《中国化学快报》2015,26(7):894-898
A novel [12]aneN3-based BODIPY sensor 1 can be applied in the sequential recognition of Cu2 and ADP in aqueous solution and living cells with high selectivity and sensitivity 相似文献
82.
基于制备接枝型分子印迹膜构建农药电位型电化学传感器及其检测性能研究 总被引:1,自引:0,他引:1
基于分子设计,以氯甲基化聚砜(CMPSF)为基膜,阴离子单体对苯乙烯磺酸钠(SSS)为功能单体,N,N'-亚甲基双丙烯酰胺(MBA)为交联剂,在表面引发体系-NH2/S2O2-8的作用下,采用"接枝聚合与分子印迹同步进行"的分子表面印迹新技术,制备了接枝型农药抗蚜威分子印迹膜(MIM)。采用红外光谱(FITR)和光学显微镜(OM)对该分子印迹膜进行表征,通过等温结合实验与竞争吸附实验,考察了抗蚜威分子印迹膜的分子识别性能与机理。以该印迹膜作为敏感膜,构建了抗蚜威电位型传感器,并对其检测性能进行了考察。结果表明,所制备的接枝型印迹膜对模板抗蚜威分子具有特异的识别选择性和优良的结合亲和性,结合容量高达92μg/cm2,相对于分子结构与抗蚜威相似的阿特拉津,印迹膜对抗蚜威的选择性系数为4.537。在p H 4.0的水介质中,传感器膜电极的电位响应与抗蚜威浓度对数在1.0×10-6~1.0×10-3mol/L范围内呈良好的线性关系(r=0.999 9),其检出限为2.5×10-8mol/L;以抗蚜威分子印迹膜为敏感膜所构建的电位型传感器,其构建过程简捷,检测灵敏准确,电位响应快速(t10 s)。 相似文献
83.
以钌(Ⅱ)多吡啶配合物[Ru(bipy)2DAFND](Cl O4)2(Ru-DAFND,bipy=2,2'-联吡啶,DAFND=4,5-二氮杂芴-9-对硝基苯腙)为指示剂,采用锁相放大技术构建了基于荧光猝灭原理的光纤DNA传感器,研究了传感器的性能。以p H 7.1的Tris缓冲溶液为介质,在2.6×10-8~5.4×10-6mol/L范围,ct DNA浓度与传感器光学敏感膜的相对滞后相移(Δφ)有较好的线性关系,检出限为8.4×10-9mol/L,响应时间为70 s。通过研究溶液p H值和干扰物对传感器性能的影响,表明该传感系统具有较好的重复性和稳定性。 相似文献
84.
本研究用氨基二茂铁(Aminoferrocene,AFc)经重氮化反应后修饰单壁碳纳米管(SWNTs),制备SWNTs-AFc复合物,并以该复合物修饰玻碳电极(GCE),通过循环伏安法(CV)和差分脉冲伏安法(DPV)等电化学方法检测对硝基苯酚(p-NP)。结果表明,与裸玻碳电极相比,SWNTs-AFc/GCE对p-NP响应的还原过电位显著减小,峰电流大大增强,p-NP的检测线性范围为1~850μmol/L(R2=0.997),检测限为1μmol/L。该方法电流响应快、灵敏度高、检测限低,具有良好的应用前景。 相似文献
85.
Ekaterina E. Stoikova Michail I. Sorvin Dmitry N. Shurpik Herman C. Budnikov Ivan I. Stoikov Gennady A. Evtugyn 《Electroanalysis》2015,27(2):440-449
A novel potentiometric sensor based on screen‐printed carbon electrode covered with electropolymerized polyaniline (PANI) and unsubstituted pillar[5]arene as ionophore has been developed and tested in potentiometric measurements of pH and metal ions. The introduction of pillar[5]arene improved the reversibility of the pH response in the range from 2.0 to 9.0 with the slope of 45 mV/pH. Among metal cations, the response to Fe3+ and Ag+ ions was referred to PANI redox conversion whereas the signal toward Cu2+ in the range from 1.0×10?6 to 1.0×10?2 M (limit of detection (LOD) 3.0×10?7 M) to specific interaction with the macrocycle. 相似文献
86.
“Green Electrodes” Modified with Au Nanoparticles Synthesized in Glycerol,as Electrochemical Nitrite Sensor 下载免费PDF全文
Dino Gobelli N. Mariano Correa M. Fátima Barroso Fernando Moyano Patricia G. Molina 《Electroanalysis》2015,27(8):1883-1891
A new environmentally friendly Au nanoparticles (Au NPs) synthesis in glycerol by using ultraviolet irradiation and without extra‐added stabilizers is described. The synthesis proposed in this work may impact on the non‐polluting production of noble nanoparticles with simple chemicals normally found in standard laboratories. These Au NPs were used to modify a carbon paste electrode (CPE) without having to separate them from the reaction medium. This green electrode was used as an electrochemical sensor for the nitrite detection in water. At the optimum conditions the green sensor presented a linear response in the 2.0×10?7–1.5×10?5 M concentration range, a good detection sensitivity (0.268 A L mol?1), and a low detection limit of 2.0×10?7 M of nitrite. The proposed modified green CPE was used to determine nitrite in tap water samples. 相似文献
87.
Electroanalytical Studies of Chromone Based Ionophores for the Selective Determination of Arsenite Ion 下载免费PDF全文
Neha Gupta Ashok Kumar Singh Shubhrajyotsna Bhardwaj Divya Singhal 《Electroanalysis》2015,27(5):1166-1175
Two chemosensors 4H‐1‐benzopyran‐3‐carboxaldehyde, 4‐oxo‐, 3‐(2‐phenylhydrazone), [I1] and 4H‐1‐benzopyran‐3‐carboxaldehyde, 4‐oxo‐, 3‐[2‐(2,4‐dinitrophenyl)hydrazone], [I2] with hydrazone‐NH group as binding site have been shown excellent selectivity for arsenite ion. It is confirmed by the UV‐vis titration that I2 is more selective than I1. The performance of the coated graphite electrode (CGE) was found to be better than polymeric membrane electrode (PME) in terms of linear range of 4.89×10?7–1.0×10?1 mol L?1, low detection limit of 8.31×10?8 mol L?1 and short response time. The proposed sensors were also used to determine the arsenite ion in different water samples. 相似文献
88.
An Antibacterial Nonenzymatic Glucose Sensor Composed of Carbon Nanotubes Decorated with Silver Nanoparticles 下载免费PDF全文
Yingzhu Liu Shan Liu Rongsheng Chen Weiting Zhan Hongwei Ni Feng Liang 《Electroanalysis》2015,27(5):1138-1143
A glucose sensor composed of silver nanoparticles decorated carbon nanotubes (Ag‐NPs/CNTs) prepared by ion implantation is described. Ag‐NPs with size of 2–4 nm are uniformly distributed in the CNTs after ion implantation. This process provides a strong combination between Ag‐NPs and CNTs and can effectively prevent the Ag‐NPs from aggregation. A linear range of 125 µM to 10 mM towards glucose determination was obtained. The Ag‐NPs/CNTs electrode shows minimal interferences from co‐existence species such as uric acid and ascorbic acid and an antibacterial rate of 94 % towards E. coli. 相似文献
89.
Impedimetric Detection of DNA Damage with the Sensor Based on Silver Nanoparticles and Neutral Red 下载免费PDF全文
Yury Kuzin Anna Porfireva Veronika Stepanova Vladimir Evtugyn Ivan Stoikov Gennady Evtugyn Tibor Hianik 《Electroanalysis》2015,27(12):2800-2808
Novel electrochemical DNA‐sensor based on glassy carbon electrode (GCE) modified with Ag nanoparticles, Neutral red covalently attached to its surface and native DNA adsorbed on modifier coating was developed for the estimation of DNA damage on example of model system based on Fenton reagent. As was shown, the oxidation process resulted in synchronous increase of electron transfer resistance and capacitance measured by electrochemical impedance spectroscopy (EIS). The contribution of each sensor component on the signal was specified and sensitivity estimated against similar surface coatings. The shift of EIS parameters was found to be higher than that of similar biosensors reported. The DNA sensor was tested on the estimation of antioxidant capacity of green tea infusions again the results of coulometric titration with electrogenerated bromine. 相似文献
90.
A Nitrite Electrochemical Sensor Based on Boron‐Doped Diamond Planar Electrochemical Microcells Modified with a Monolacunary Silicotungstate Polyoxoanion 下载免费PDF全文
Yosra Sahraoui Amel Sbartai Sana Chaliaa Abderrazak Maaref Amor Haddad Nicole Jaffrezic‐Renault 《Electroanalysis》2015,27(6):1359-1367
A new boron doped diamond microcells (BDD) was modified, for rapid, selective and highly sensitive determination of nitrite, using a coating film of polyoxometalates (POMs), formed by cyclic voltammetry on the molecular p‐phenylenediamine (PPD) functionalized BDD. The scanning electron microscopy (SEM) technique was used to examine the morphology of (PPD/SiW11) modified (BDD) electrode. It was found that (SiW11) layer was uniformly formed on the electrode surface. It was observed that (BDD/PPD/SiW11) showed excellent electrocatalytic activities towards nitrite ion. Under the selected conditions, the anodic peak maximum at ?0.6 V was linear versus nitrite concentration in the 40 µM–4 mM range, and the detection limit obtained was 20 µM. The newly developed electrode has been successfully applied to the determination of nitrite content in real river water samples. 相似文献