全文获取类型
收费全文 | 184篇 |
免费 | 8篇 |
专业分类
化学 | 161篇 |
晶体学 | 2篇 |
数学 | 7篇 |
物理学 | 22篇 |
出版年
2023年 | 2篇 |
2022年 | 5篇 |
2021年 | 5篇 |
2020年 | 4篇 |
2019年 | 6篇 |
2018年 | 5篇 |
2017年 | 1篇 |
2016年 | 4篇 |
2015年 | 4篇 |
2014年 | 6篇 |
2013年 | 18篇 |
2012年 | 10篇 |
2011年 | 9篇 |
2010年 | 3篇 |
2009年 | 7篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 14篇 |
2005年 | 12篇 |
2004年 | 12篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 1篇 |
1997年 | 1篇 |
1996年 | 1篇 |
1995年 | 1篇 |
1994年 | 1篇 |
1992年 | 5篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 1篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1981年 | 1篇 |
1978年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1944年 | 2篇 |
1939年 | 1篇 |
1938年 | 1篇 |
1933年 | 1篇 |
1932年 | 2篇 |
1928年 | 1篇 |
1906年 | 1篇 |
排序方式: 共有192条查询结果,搜索用时 46 毫秒
101.
102.
Alkylation and intramolecular palladium-catalyzed arylation allows for the ready synthesis of C57H33N3 from symmetrical triindole, a triaza analogue of truxene. 相似文献
103.
Cebrián-Losantos B Krokhin AA Stepanenko IN Eichinger R Jakupec MA Arion VB Keppler BK 《Inorganic chemistry》2007,46(12):5023-5033
The osmium(III) complex [(DMSO)2H][trans-OsIIICl4(DMSO)2] (1) has been prepared via stepwise reduction of OsO4 in concentrated HCl using N2H(4).2HCl and SnCl(2).2H2O in DMSO. 1 reacts with a number of azole ligands, namely, indazole (Hind), pyrazole (Hpz), benzimidazole (Hbzim), imidazole (Him), and 1H-1,2,4-triazole (Htrz), in organic solvents, affording novel complexes (H2ind)[OsIIICl4(Hind)(DMSO)] (2), (H2pz)[OsIIICl4(Hpz)(DMSO)] (3), (H2bzim)[OsIIICl4(Hbzim)(DMSO)] (4), (H2im)[OsIIICl4(Him)(DMSO)] (6), and (H2trz)[OsIIICl4(Htrz)(DMSO)] (7), which are close analogues of the antimetastatic complex NAMI-A. Metathesis reaction of 4 with benzyltriphenylphosphonium chloride in methanol led to the formation of (Ph3PCH2Ph)[OsIIICl4(Hbzim)(DMSO)] (5). The complexes were characterized by IR, UV-vis, ESI mass spectrometry, 1H NMR spectroscopy, cyclic voltammetry, and X-ray crystallography. In contrast to NAMI-A, 2-4, 6, and 7 are kinetically stable in aqueous solution and resistant to hydrolysis. Surprisingly, they show reasonable antiproliferative activity in vitro in two human cell lines, HT-29 (colon carcinoma) and SK-BR-3 (mammary carcinoma), when compared with analogous ruthenium compounds. Structure-activity relationships and the potential of the prepared complexes for further development are discussed. 相似文献
104.
105.
Conformational analysis of 1-amino-3-butene and 3-butene-1-thiol was carried out using the 4-21G basis set. The conformers obtained were subjected to 6-31G* single-point analysis for the calculation of energies, charge distributions, and dipole moments. The geometries and stabilities obtained are in good agreement with available experimental data. The results are interpreted in terms of intramolecular hydrogen bonding and anomeric interactions: Some of the most stable conformers of both molecules have intramolecular hydrogen bonds between the hydrogens of the amino or thiol groups and the electrons of the double bond. The 4-21G geometries were refined to obtain rotational constants closer to the experimental values. 相似文献
106.
Metallation of thiols RFC2H4SH followed by alkylation with iodides R′FC2H4I leads either to symmetrical or to unsymmetrical sulphides RFC2H4SC2H4R′F (with RF=R′F or RF ≠ R′F). All compounds obtained are good solvents of gases (particularly O2, CO, CO2, N2).This property allows their application as biological carriers of dissolved gases. 相似文献
107.
108.
Rosa Carballo Berta Covelo Ezequiel M. Vzquez‐Lpez Alfonso Castieiras Juan Nicls 《无机化学与普通化学杂志》2002,628(2):468-472
The cobalt(II) complexes [Co(HL1)2(H2O)2]·H2O) ( 1 ) and [Co(HL2)2(H2O)2]( 2 ) [(HL1)‐ = (/plusmn;)‐lactate, (HL2)‐ = 2‐Methyl‐lactate] were prepared and characterized structurally. The cobalt atom is in a distorted octahedral environment in both compounds. Both α‐hydroxycarboxylato ligands are O, O'‐bidentate chelating monoanions. The presence of a lattice water molecule in 1 makes its supramolecular organization different from that of 2 . The thermal behaviour of both compounds was also investigated. 相似文献
109.
Franguelli Fernanda Paiva Barta-Holló Berta Petruševski Vladimir M. Sajó Istvan E. Klébert Szilvia Farkas Attila Bódis Eszter Szilágyi Imre Miklós Pawar Rajendra P. Kótai László 《Journal of Thermal Analysis and Calorimetry》2021,145(6):2907-2923
Journal of Thermal Analysis and Calorimetry - Detailed vibrational (IR, Raman, far-IR) and thermal (TGA, TG–MS, DSC) analysis has been performed on... 相似文献