全文获取类型
收费全文 | 102篇 |
免费 | 1篇 |
国内免费 | 20篇 |
专业分类
化学 | 100篇 |
晶体学 | 1篇 |
力学 | 3篇 |
综合类 | 5篇 |
数学 | 2篇 |
物理学 | 12篇 |
出版年
2024年 | 1篇 |
2023年 | 5篇 |
2022年 | 7篇 |
2021年 | 6篇 |
2020年 | 5篇 |
2019年 | 9篇 |
2018年 | 5篇 |
2017年 | 2篇 |
2016年 | 5篇 |
2015年 | 1篇 |
2014年 | 4篇 |
2013年 | 10篇 |
2012年 | 10篇 |
2011年 | 6篇 |
2010年 | 6篇 |
2009年 | 1篇 |
2008年 | 3篇 |
2007年 | 2篇 |
2006年 | 4篇 |
2005年 | 2篇 |
2004年 | 2篇 |
2003年 | 5篇 |
2001年 | 3篇 |
2000年 | 2篇 |
1999年 | 1篇 |
1997年 | 5篇 |
1996年 | 5篇 |
1995年 | 3篇 |
1993年 | 1篇 |
1990年 | 1篇 |
1983年 | 1篇 |
排序方式: 共有123条查询结果,搜索用时 0 毫秒
51.
Xiaohui He Suli Wang Yingping Yang Guangshui Tu Feng Zhang Shengmei Huang Yapeng Duan Chuanyi Zhu Changwen Cheng Defu Chen 《应用有机金属化学》2019,33(2)
Two C–C bridged Ni(II) complexes bearing β‐keto‐9‐fluorenyliminato ligands with electron‐withdrawing groups (─CF3), Ni{PhC(O)CHC[N(9‐fluorenyl)]CF2}2 (Ni 1 ) and Ni{CF3C(O)CHC[N(9‐fluorenyl)]Ph}2 (Ni 2 ), were synthesized by metal coordination reaction and different in situ bonding mechanisms. The C–C bridged bonds of Ni 1 were formed by in situ intramolecular trifluoromethyl and 9‐fluorenyl carbon–carbon cross‐coupling reaction and those of Ni 2 were formed by in situ intramolecular 9‐fluorenyl carbon–carbon radical coupling reaction mechanism. The obtained complexes were characterized using 1H NMR spectroscopy and elemental analyses. The crystal and molecular structures of Ni 1 and Ni 2 with C–C bridged configuration were determined using X‐ray diffraction. Ni 1 and Ni 2 were used as catalysts for norbornene (NB) polymerization after activation with B(C6F5)3 and the catalytic activities reached 106 gpolymer molNi?1 h?1. The copolymerization of NB and styrene catalyzed by the Ni 1 /B(C6F5)3 system showed high activity (105 gpolymer molNi?1 h?1) and the catalytic activities decreased with increasing feed content of styrene. All vinyl‐type copolymers exhibited high molecular weight (104 g mol?1), narrow molecular weight distribution (Mw/Mn = 1.71–2.80), high styrene insertion ratios (11.13–50.81%) and high thermal stability (Td > 380°C) and could be made into thin films with high transparency in the visible region (400–800 nm). 相似文献
52.
Hong Shaoming Ren Huijun Fang Yanfeng Huang Yingping Li Ruiping 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2018,92(5):984-991
Russian Journal of Physical Chemistry A - Three-dimensionally (3D) BiOBr microflowers were prepared by a simple solvothermal method, employing Bi(NO3)3 · 5H2O and NaBr as starting reagents in... 相似文献
53.
Fang Yanfen Cao Xinqiang Zhou Wei Li Yue Johnson David M. Huang Yingping 《Research on Chemical Intermediates》2020,46(2):1141-1152
Research on Chemical Intermediates - There are increasing concerns about detoxification of microcystin-LR (MC-LR) over the past few decades. Nevertheless, the removal of MC-LR in water by... 相似文献
54.
Tao Wang Liuliu Feng Jun Yuan Lihui Jiang Wei Deng Zhi-Guo Zhang Yongfang Li Yingping Zou 《中国科学:化学(英文版)》2018,61(2):206-214
A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC71BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G, 100 mW cm?2, which is the highest value for PP-based PSCs. 相似文献
55.
Tao Wang Liuliu Feng Jun Yuan Lihui Jiang Wei Deng Zhi-Guo Zhang Yongfang Li Yingping Zou 《中国科学:化学(英文版)》2018,(2)
A series of new polymer donors (PT-PP, PT-2fPP and PT-4fPP) were synthesized based on alkylthiophene substituted benzodithiophene (BDT-T) and pyrido[3,4-b]pyrazine (PP) building blocks and the effects of fluorination on the polymer properties were explored. Photophysical properties, charge mobilities and morphologies of the three polymers have been intensively investigated. The results indicated that the introduction of the fluorine atom at meta-positions of phenyl substituted PP unit hardly affected their highest occupied molecular orbital (HOMO) level. More importantly, controlling the degree of side-chain fluorination in the polymers is crucial for optimizing the blend morphology. Three polymers showed different photovoltaic properties. The polymer solar cell (PSC) based on the single layer device structure of ITO/PEDOT:PSS/PT-4fPP:PC71BM (1:1, w:w)/ZrAcac/Al demonstrates a high power conversion efficiency (PCE) of 7.61% under the illumination of AM 1.5G,100 mW cm-2, which is the highest value for PP-based PSCs. 相似文献
56.
应用紫外-可见吸收光谱法研究细胞细色素C(Fecty-C)活性中心铁离子在pH7.1的磷酸缓冲液中与4种微量元素M(Ⅱ)的直接相互作用。结果表明,细胞色素C(Fecyt-C)活性中心Fe(Ⅱ)离子可被微量元素M(Ⅱ)部分取代,形成部分的细胞色素C衍生物(Mcyt-C),溶液的吸收光谱的Soret带最大吸收峰发生蓝移,且α带与β带最大吸收峰相对峰强减弱。 相似文献
57.
Xiaohui He Yingjiao Deng Zhilong Han Yingping Yang Defu Chen 《Journal of polymer science. Part A, Polymer chemistry》2016,54(21):3495-3505
Three new three‐dimensional geometry bulky α‐diimine ligands ( L ) containing electron‐donating and electron‐withdrawing groups, 9,10‐dihydro‐9,10‐ethanoanthracene‐11,12‐di(Ar)imine (Ar = p‐PhCH3, L1 ; Ar=p‐PhCl, L2 ; Ar=p‐PhCF3, L3 .), and their corresponding single Ni(II) catalysts, NiL2Br2 ( Ni(L1)2Br2 , Ni(L2)2Br2 , and Ni(L3)2Br2 , were synthesized and the molecular structure were determined by X‐ray crystallography. All NiL2Br2 catalysts were tested for norbornene polymerization and copolymerization of norbornene with 1‐alkene after activation with B(C6F5)3. The results that the polymerization catalytic activities for norbornene up to 105 gpolymer/molNi·h even at 140 °C, shown that NiL2Br2 catalysts have high thermal stability. Meanwhile, catalysts with electron‐withdrawing groups could achieve higher reactivity. The obtained poly(NB‐co‐1‐alkene)s were confirmed to be vinyl‐addition copolymers and noncrystalline. All copolymers exhibited high 1‐alkenes insertion ratio, good thermal stability (Td > 375 °C), high molecular weight (up to 105 g/mol), good solubility in common organic solvents and could be processed into films with good transparency in the visible region. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3495–3505 相似文献
58.
单粒子气溶胶的基质辅助激光解吸/电离飞行时间质谱技术具有快速在线检测环境大气生物气溶胶的潜力.以α-环糊精为分析物,实验研究了吡啶羧酸、2,5-二羟基苯甲酸、芥子酸、阿魏酸四种常用基质材料的效果,考察基质与分析物的摩尔比对分析物单粒子激光质谱信号的影响.实验结果表明阿魏酸做基质时质谱命中率及分析物质谱信号峰检测效率最高,吡啶羧酸做基质时的分析物质谱信号峰激发率最高,信号峰强度最强.吡啶羧酸对分析物摩尔比为100:1时,分析物质谱信号检测效率最高. 相似文献
59.
60.
Two alternative copolymers of thieno[3,4b]pyrazine (TPZ) and triphenylamine (TPA) or phenylene (Ph), P(TPA‐TPZ) and P(Ph‐TPZ), were synthesized by Wittig–Horner polycondensation and characterized by 1H NMR, elemental analysis, GPC, TGA, cyclic voltammetry, UV–Vis absorption, and photoluminescence (PL) spectroscopy. The polymers are soluble in common organic solvents and possess good thermal stability. Both of them shows strong solvatochromism phenomenon when dissolved in different solvents. The fluorescence of the copolymer solutions is efficiently quenched upon the addition of Hg2+, indicating that the two copolymers could be good Hg2+ detectors. More interestingly, the copolymers show high selectivity for the Hg2+ detection and P(TPA‐TPZ) shows higher sensitivity and selectivity toward the Hg2+ detection than P(Ph‐TPZ) does in the presence of other competing metal ions. The results imply that the conjugated polymers (CPs) containing the thieno[3,4b]pyrazine moiety are promising materials for chemosensors. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献