全文获取类型
收费全文 | 1005篇 |
免费 | 22篇 |
国内免费 | 4篇 |
专业分类
化学 | 753篇 |
晶体学 | 22篇 |
力学 | 5篇 |
数学 | 58篇 |
物理学 | 193篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 9篇 |
2019年 | 7篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 15篇 |
2014年 | 22篇 |
2013年 | 44篇 |
2012年 | 27篇 |
2011年 | 35篇 |
2010年 | 22篇 |
2009年 | 26篇 |
2008年 | 46篇 |
2007年 | 55篇 |
2006年 | 59篇 |
2005年 | 41篇 |
2004年 | 43篇 |
2003年 | 32篇 |
2002年 | 36篇 |
2001年 | 37篇 |
2000年 | 26篇 |
1999年 | 18篇 |
1998年 | 20篇 |
1997年 | 24篇 |
1996年 | 13篇 |
1995年 | 17篇 |
1994年 | 18篇 |
1993年 | 24篇 |
1992年 | 19篇 |
1991年 | 21篇 |
1990年 | 18篇 |
1989年 | 21篇 |
1988年 | 7篇 |
1987年 | 11篇 |
1986年 | 6篇 |
1985年 | 22篇 |
1984年 | 19篇 |
1983年 | 6篇 |
1982年 | 22篇 |
1981年 | 15篇 |
1980年 | 25篇 |
1979年 | 10篇 |
1978年 | 11篇 |
1977年 | 13篇 |
1976年 | 7篇 |
1975年 | 8篇 |
1974年 | 9篇 |
1973年 | 7篇 |
1971年 | 4篇 |
排序方式: 共有1031条查询结果,搜索用时 359 毫秒
11.
Toshiki Kono Toshikazo Sakaguchi Yanming Hu Masashi Shiotsuki Fumio Sanda Toshio Masuda 《Journal of polymer science. Part A, Polymer chemistry》2006,44(20):5943-5953
Phenylacetylene (PA) derivatives having two polar groups (ester, 2a – d ; amide, 4) or one cyclic polar group (imide, 5a – c ) were polymerized using (nbd)Rh+[(η6‐C6H5)B?(C6H5)3] catalyst to afford high molecular weight polymers (~1 × 106 – 4 × 106). The hydrolysis of ester‐containing poly(PA), poly( 2a) , provided poly(3,4‐dicarboxyPA) [poly ( 3 )], which could not be obtained directly by the polymerization of the corresponding monomer. The solubility properties of the present polymers were different from those of poly(PA) having no polar group; that is, poly( 2a )–poly( 2d ) dissolved in ethyl acetate and poly( 4 ) dissolved in N,N‐dimethylformamide, while poly(PA) was insoluble in such solvents. Ester‐group‐containing polymers [poly( 2a )–poly( 2d )] afforded free‐standing membranes by casting from THF solutions. The membrane of poly( 2a ) showed high carbon dioxide permselectivity against nitrogen (PCO2/PN2 = 62). © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 5943–5953, 2006 相似文献
12.
13.
14.
Katsunori Nishimura Rie Hidaka Fumitoshi Hirayama Hidetoshi Arima Kaneto Uekama 《Journal of inclusion phenomena and macrocyclic chemistry》2006,54(1-2):85-88
Geometries, electronic properties and NMR-shielding of cucurbit[5]uril, decamethylcucurbit[5]uril, cucurbit[6]uril, cucurbit[7]uril,
and cucurbit[8]uril are investigated with DFT calculations. All molecules are highly symmetrical with a distinct geometric
flexibility. In addition with a characteristic partial charge distribution these findings account for their chemical complex
building ability. 相似文献
15.
Synthesis and structures of the title compounds 2a–d are described. In spite of non-parallel orientation of the two base rings, fairly large hypochromism was observed for 2a–d. 相似文献
16.
The title racemate-to-conglomerate transformation which occurs in the solid state on heating or contact with MeOH vapour has been studied by IR and DTA spectral measurements, microscopic observation, and by X-ray structural and X-ray powder diffraction analysis. 相似文献
17.
18.
Some o-xylylene (o-quinodimethane) derivatives were isolated as stable cyrstalline materials. A strong through-bond interaction in tetracyanoethylene addition product of tetraphenylbenzodicyclobutadiene ( is suggested. 相似文献
19.
20.
Fumio Hamada Kyoko Ishikawa Riko Ito Hisanori Shibuya Sanyo Hamai Iwao Suzuki Tetsuo Osa Akihiko Ueno 《Journal of inclusion phenomena and macrocyclic chemistry》1994,20(1):43-51
-Cyclodextrin with two sodium anthranilate moieties (1) has been prepared as a sensor for detecting organic compounds including terpenoids and steroids. Compound1 shows a pure monomer fluorescence whose intensity is increased or decreased upon addition of the guest species examined. In this system, the sodium anthranilate moieties act either as a spacer, which enables the cyclodextrin to form a 1:1 host-guest complex by narrowing the -cyclodextrin cavity, or as a hydrophobic cap.1 recognizes steroids with much higher sensitivity than terpenoids, in which the appended moieties act as a hydrophobic cap for terpenoids and a spacer for steroids, respectively. 相似文献