全文获取类型
收费全文 | 37517篇 |
免费 | 1311篇 |
国内免费 | 1025篇 |
专业分类
化学 | 16849篇 |
晶体学 | 383篇 |
力学 | 1784篇 |
综合类 | 61篇 |
数学 | 9734篇 |
物理学 | 11042篇 |
出版年
2023年 | 181篇 |
2022年 | 275篇 |
2021年 | 334篇 |
2020年 | 370篇 |
2019年 | 331篇 |
2018年 | 1432篇 |
2017年 | 1665篇 |
2016年 | 1127篇 |
2015年 | 913篇 |
2014年 | 904篇 |
2013年 | 1278篇 |
2012年 | 3925篇 |
2011年 | 3115篇 |
2010年 | 2283篇 |
2009年 | 2025篇 |
2008年 | 1111篇 |
2007年 | 1142篇 |
2006年 | 1055篇 |
2005年 | 4845篇 |
2004年 | 4178篇 |
2003年 | 2473篇 |
2002年 | 686篇 |
2001年 | 468篇 |
2000年 | 266篇 |
1999年 | 323篇 |
1998年 | 251篇 |
1997年 | 180篇 |
1996年 | 150篇 |
1995年 | 177篇 |
1994年 | 159篇 |
1993年 | 110篇 |
1992年 | 247篇 |
1991年 | 226篇 |
1990年 | 206篇 |
1989年 | 142篇 |
1988年 | 145篇 |
1987年 | 92篇 |
1986年 | 78篇 |
1985年 | 68篇 |
1984年 | 51篇 |
1982年 | 38篇 |
1979年 | 36篇 |
1976年 | 86篇 |
1975年 | 44篇 |
1974年 | 46篇 |
1973年 | 51篇 |
1972年 | 39篇 |
1970年 | 37篇 |
1969年 | 37篇 |
1966年 | 40篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
301.
Semih?Calamak Eda?Ayse?Aksoy Ceren?Erdogdu Meral?Sag?roglu Kezban?UlubayramEmail author 《Journal of nanoparticle research》2015,17(2):87
Development of new generation bionanotextiles is an important growing field, and they have found applications as wound dressings, bandages, tissue scaffolds, etc. In this study, silver nanoparticle (AgNP) containing silk-based bionanotextiles were fabricated by electrospinning, and processing parameters were optimized and discussed in detail. AgNPs were in situ synthesized within fibroin nanofibers by UV reduction of silver ions to metallic silver. The influence of post-treatments via methanol treatment and glutaraldehyde (GA) vapor exhibited changes in the secondary structure of silk. Methanol treatment increased the tensile properties of fibers due to supported crystalline silk structure, while GA vapor promoted amorphous secondary structure. AgNP containing silk fibroin bionanotextiles had strong antibacterial activity against gram-positive Staphylococcus aureus and gram-negative Pseudomonas aeruginosa. 相似文献
302.
Jan?C.?Myland Keith?B.?OldhamEmail author 《Journal of Solid State Electrochemistry》2014,18(12):3259-3269
The popular inlaid disc electrode suffers from an edge effect that is usually, and sometimes unwarrantedly, ignored in analyzing transient voltammograms. This study addresses the role played by the edge in linear scan and cyclic voltammetries when the electron transfer is reversible or quasi-reversible. A simulation models the concentrations, current densities and currents in two circumstances—when the edge in important and when it is absent—simultaneously, and thereby the evolving edge current is quantified. Special attention is paid to the effect that the edge has on the heights and positions of the voltammetric peaks. It is demonstrated that disregarding the edge may lead to the bogus classification of a reversible electrode reaction as quasi-reversible. 相似文献
303.
304.
Guan Wu ;Ran Ran ;Bote Zhao ;Yujing Sha ;Chao Su ;Yingke Zhou ;Zongping Shao 《天然气化学杂志》2014,(3):363-375
Amorphous carbon and graphene co-modified LiFePO_4 nanocomposite has been synthesized via a facile polyol process in connection with a following thermal treatment.Various characterization techniques,including XRD.Mossbauer spectra,Raman spectra,SEM,TEM,BET,O_2-TPO,galvano charge-discharge,CV and EIS were applied to investigate the phase composition,carbon content,morphological structure and electrochemical performance of the synthesized samples.The effect of introducing way of carbon sources on the properties and performance of LiFePO_4/C/graphene composite was paid special attention.Under optimized synthetic conditions,highly crystalized olivine-type LiFePO_4was successfully obtained with electron conductive Fe_2P and FeP as the main impurity phases.SEM and TEM analyses demonstrated the graphene sheets were randomly distributed inside the sample to create an open structured LiFePO_4 with respect to graphene,while the glucosederived carbon mainly coated over LiFeP04 particles which effectively connected the graphene sheets and LiFePO_4 particles to result in a more efficient charge transfer process.As a result,favorable electrochemical performance was achieved.The performance of the amorphous carbon-graphene co-modified LiFePO_4 was further progressively improved upon cycling in the first 200 cycles to reach a reversible specificcapacity as high as 97 mAh·g~(-1) at 10 C rate. 相似文献
305.
Saeromi Chung Mahmood H. Akhtar A. Benboudiaf Deog‐Su Park Yoon‐Bo Shim 《Electroanalysis》2020,32(3):520-527
An electrochemical sensor based on the conducting polymer composite with a palladium complex (Pd(C2H4N2S2)2) was developed for the detection of serotonin and dopamine simultaneously in the breast cancer cell and human plasma samples. The proposed sensor was fabricated using the Pd(C2H4N2S2)2 complex‐anchored poly2,2 : 5,2‐terthiophene‐3‐(p‐benzoic acid) (pTBA) layer on the AuNPs decorated reduced graphene oxide (AuNPs@rGO) substrate, which revealed the enhanced anodic current of the target species. The sensor probe was characterized by electrochemical and surface analysis methods. The experimental parameters affecting the sensor performance were optimized, in terms of AuNPs@rGO concentration, the number of electropolymerization cycle for pTBA, immobilization time of Pd(C2H4N2S2)2, and pH. The dynamic ranges for serotonin and dopamine were obtained from 0.02 to 200 μM, and from 0.1 to 200 μM with the detection limit of 2.5, and 24.0 nM, respectively. The reliability of proposed sensor was evaluated using cancer cell lines for the clinical applications. 相似文献
306.
Nonlinear Dynamics - Combining the complex factors of mechanical impact, Coulomb friction, harmonic excitation, and Gaussian white noise, an electromagnetic energy harvesting system is analytically... 相似文献
307.
308.
通过引入电子性作用V_c,在弱耦合条件下导出了两带模型的T_c公式和同位素效应指数公式,计算了超导体MgB_2的超导转变温度和同位素效应,得到了与实验相符的结果。结果表明,带内电子性作用比带间电子性作用对同位素效应指数的影响要大。 相似文献
309.
310.