全文获取类型
收费全文 | 17034篇 |
免费 | 2815篇 |
国内免费 | 3129篇 |
专业分类
化学 | 13896篇 |
晶体学 | 288篇 |
力学 | 773篇 |
综合类 | 265篇 |
数学 | 1822篇 |
物理学 | 5934篇 |
出版年
2024年 | 17篇 |
2023年 | 291篇 |
2022年 | 407篇 |
2021年 | 571篇 |
2020年 | 690篇 |
2019年 | 712篇 |
2018年 | 596篇 |
2017年 | 594篇 |
2016年 | 815篇 |
2015年 | 884篇 |
2014年 | 1103篇 |
2013年 | 1486篇 |
2012年 | 1582篇 |
2011年 | 1649篇 |
2010年 | 1263篇 |
2009年 | 1119篇 |
2008年 | 1307篇 |
2007年 | 1220篇 |
2006年 | 1058篇 |
2005年 | 871篇 |
2004年 | 705篇 |
2003年 | 583篇 |
2002年 | 537篇 |
2001年 | 502篇 |
2000年 | 409篇 |
1999年 | 373篇 |
1998年 | 256篇 |
1997年 | 213篇 |
1996年 | 193篇 |
1995年 | 184篇 |
1994年 | 155篇 |
1993年 | 125篇 |
1992年 | 87篇 |
1991年 | 86篇 |
1990年 | 82篇 |
1989年 | 36篇 |
1988年 | 43篇 |
1987年 | 23篇 |
1986年 | 39篇 |
1985年 | 28篇 |
1984年 | 19篇 |
1983年 | 17篇 |
1982年 | 9篇 |
1981年 | 10篇 |
1980年 | 5篇 |
1979年 | 4篇 |
1976年 | 3篇 |
1974年 | 2篇 |
1973年 | 3篇 |
1957年 | 4篇 |
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
991.
992.
993.
WANG Zhi-xin HOU Yi HAN Wei WANG Kai-chen GUO Bao-feng LIU Ying CHANG Xi-hua WANG Wei-hua NA Wan-li KONG Xiang-bo ZHAO Xu ZHANG Ling 《高等学校化学研究》2011,27(1):94-98
Renal cell carcinoma is the most common cancer of the kidney, and resistant to traditional therapies. The aim of this study is to investigate the effects of hydroxyapatite nanoparticles on human renal cell carcinoma 786-0 cells. Cell proliferation was assessed with an 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide(MTT) staining kit. The apoptosis assay was assessed with an FITC Annexin V Apoptosis Detection Kit. Caspase-3 and caspase-12 were detected by immunocytochemical staining and semi-qua... 相似文献
994.
995.
One solid-state electrochemiluminescence(ECL) protein biosensor based on the competing reaction and substitute reaction between protein-to-DNA aptamer and DNA-to-DNA aptamer was proposed.Additionally,the biosensor was based on ECL photo-quenching effect of ferrocene(Fc) to tris(2,2'-bipyridyl)ruthenium(II)(Ru(bpy)32+).It was built up by modification of Au nanoparticles(AuNPs) and Ru(bpy)3 2+ on one Au electrode firstly,and then self-assembly of one special double-stranded DNA(dsDNA) onto the electrode.This ... 相似文献
996.
WANG Ming LI Ying XIE ZhiYuan & WANG LiXiang State Key Laboratory of Polymer Physics Chemistry Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun China 《中国科学B辑(英文版)》2011,(4)
A series of conjugated copolymers of 9,9-dioctylfluorene and symmetrical pyrazine unit (BY) were synthesized by Suzuki copolymerization and were used as novel light-emitting materials in PLEDs.Efficient energy transfer was observed in both thin film and solution.Compared with the lowest occupied molecular orbital (LUMO) energy level of the polyfluorenes homopolymer (PFO),the lower LUMO energy levels of copolymers indicated that the introduction of the BY unit would be benefit to electron injection.The turn-... 相似文献
997.
998.
An amperometric sensor for the determination of indole-3-acetic acid (IAA) based on the CeCl3-DHP film modified gold electrode was developed. CeCl3 was dissolved into water in the presence of dihexadecyl hydrogen phosphate (DHP). The IAA sensor was prepared via evaporating
solvent of the CeCl3-DHP dispersion on the gold electrode surface. The amperometric response of IAA on the CeCl3-DHP film modified gold electrode was investigated. The experimental results indicate that the passivation of the electrode
due to the adsorption of the oxidation product of IAA decreases significantly at the CeCl3-DHP film modified gold electrode, in contrast to that at the bare and the DHP modified gold electrode. The experimental parameters
were optimized and an electrochemical method for the determination of IAA was established. The oxidation peak current is linearly
with the concentration of IAA from 1 × 10−7 to 2 × 10−5 mol l−1 and the detection limit is 3 × 10−8 mol l−1. The relative standard deviation of eight measurements is 3.2% for 5 × 10−7 mol l−1 IAA. The IAA in plant leaves were extracted and determined by the IAA sensor. 相似文献
999.
A novel nanocomposite integrating the good biocompatibility of polyacrylic resin nanoparticles (PAR) and the good conductivity of colloidal gold nanoparticles was proposed to construct the matrix for the immobilization of hemoglobin (Hb) on the surface of a glassy carbon electrode (GCE). UV‐vis spectra demonstrated that Hb preserved its native structure after being entrapped into the composite film. The direct electrochemistry of hemoglobin (Hb) in this nanocomposite films showed a pair of well‐defined and quasi‐reversible cyclic voltammetric peaks with a formal potential of ?0.307 mV and a constant electron transfer rate of 2.51±0.2 s?1. The resultant amperometric biosensor showed fast responses to the analytes with excellent detection limits of 0.2 µM for H2O2 and 0.89 µM for TCA (S/N=3), and high sensitivity of 1108.6 for H2O2 and 77.14 mA cm?2 M?1 for TCA, respectively. The linear current response was found in the range from 0.59 to 7.3 µM (R2=0.9996) for H2O2 and from 5 to 85 µM (R2=0.9996) for TCA, while the superior apparent Michaelis–Menten constant was 0.012 mM for H2O2 and 0.536 mM for TCA, respectively. Therefore, the PAR‐Au‐Hb nanocomposite as a novel matrix opens up a possibility for further study on the direct electrochemistry of other proteins. 相似文献
1000.
Han‐Guang Wu Xiao‐Jie Ju Rui Xie Ying‐Mei Liu Jin‐Gen Deng Catherine Hui Niu Liang‐Yin Chu 《先进技术聚合物》2011,22(9):1389-1394
A novel ion‐imprinted strategy is developed for synthesizing responsive hydrogels with rapid response to potassium ions. With potassium ions as templates, ion‐imprinted poly(N‐isopropylacrylamide‐co‐benzo‐15‐crown‐5‐acrylamide) (P(NIPAM‐co‐B15C5Am)) hydrogels are synthesized with 15‐crown‐5 crown ethers mounted on the polymer networks in pairs; therefore, it is very easy and fast for the crown ethers to capture potassium ions again by their Venus flytrap action and form stable 2:1 “host–guest” complexes with potassium ions in the ion‐recognition process. As a result, the response rate of the ion‐imprinted hydrogels to potassium ions is significantly faster than that of normal P(NIPAM‐co‐B15C5Am) hydrogels in which 15‐crown‐5 crown ethers are randomly pendent on the polymeric networks. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献