全文获取类型
收费全文 | 224篇 |
免费 | 3篇 |
国内免费 | 1篇 |
专业分类
化学 | 99篇 |
晶体学 | 1篇 |
力学 | 20篇 |
数学 | 72篇 |
物理学 | 36篇 |
出版年
2022年 | 4篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 5篇 |
2018年 | 13篇 |
2017年 | 5篇 |
2016年 | 4篇 |
2015年 | 2篇 |
2014年 | 7篇 |
2013年 | 9篇 |
2012年 | 15篇 |
2011年 | 11篇 |
2010年 | 11篇 |
2009年 | 13篇 |
2008年 | 4篇 |
2007年 | 1篇 |
2006年 | 5篇 |
2005年 | 6篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 3篇 |
2001年 | 6篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 5篇 |
1997年 | 5篇 |
1996年 | 3篇 |
1995年 | 3篇 |
1994年 | 6篇 |
1993年 | 6篇 |
1992年 | 8篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 5篇 |
1988年 | 5篇 |
1987年 | 3篇 |
1986年 | 1篇 |
1985年 | 3篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 1篇 |
1977年 | 1篇 |
1976年 | 1篇 |
1972年 | 1篇 |
1971年 | 2篇 |
排序方式: 共有228条查询结果,搜索用时 0 毫秒
1.
Unstable form changing (click) of an arched TiNi strip annealed at 773 K is investigated. After the annealing, the strip is
placed into the grips of a deforming machine and is transferred to the martensitic state by bending in the direction opposite
to its initial bend. Subsequent heating of the strip, which carries it to the austenitic state, is accompanied by a click
under the conditions of constrained form changing. Analysis of the martensitic deformation in terms of the theory of diffuse
martensitic transformations makes it possible to establish the conditions under which the form changing process becomes unstable. 相似文献
2.
The bromination of 3-bromo-6, 7-benzobicyclo [3.2.1] octa-2, 6-diene at ?50°C has been found to give only one product, the tribromide(7) produced via Wagner-Meerwein rearrangement with accompanying aryl migration. The bromination at 0°C produced nonrearranged tribromides beside the rearranged product. The structures of the products were determined by means of spectral data. The addition mechanism is discussed in terms of exo- and endo-attack. 相似文献
3.
4.
G. A. Zou S. Mansur S. C. Hu H. A. Aisa Kh. M. Shakhidoyatov 《Chemistry of Natural Compounds》2012,48(4):635-637
The novel pyrrole alkaloid alhagifoline A (1) together with the two known analogs pyrrolezanthine (2) and pyrrolezanthine-6-methyl ether (3) were isolated from the aerial part of Alhagi sparsifolia. Their structures were established based on spectral (HR-ESI-MS, 1 H and 13C NMR, 1 H–1 H COSY, HSQC, HMBC) data. Compounds 2 and 3 were isolated from the genus Alhagi for the first time. 相似文献
5.
6.
7.
Bromination of 3-bromo-6,7-benzobicyclo [3.2.1] octa-2,6-diene at ?50°C gave anti-tribromo adduct (5) in essentially quantitative yield. The double dehydrobromination of (5) was achieved using potassium tert.- butoxide to give 2-bromo-benzobarrelene (7). Reaction of (7) with n-BuLi and subsequent quenching with CH3I, CO2, and dimethylformamide afforded the corresponding substituted benzobarrelenes in high yield. 相似文献
8.
9.
A. Mushtaq M. S. Mansur Ali Muhammad 《Journal of Radioanalytical and Nuclear Chemistry》1996,212(2):107-115
Hydrated antimony pentoxide (HAP) as an absorbent for column operation has been prepared by hydrolysis of SbCl5 with deionized water. Sorption behavior of Sn, Cd, Sb and In was studied on HAP in HCl medium. Radiochemical separation of no-carrier added113mIn from113Sn/125Sb and115mIn from115Cd wa achieved over a HAPO column. The separated products were of high radionuclidic purity. 相似文献
10.
Mansur B. Ibrahim Rami Suleiman Mohammed Fettouhi Bassam El Ali 《Transition Metal Chemistry》2017,42(1):1-8
A palladium(II)-bis(oxazoline) complex supported on silica (Pd-BOX-Si) was prepared, characterized and applied as a catalyst in Mizoroki–Heck cross-coupling reactions. The bis(oxazoline) (BOX) ligand has a hydroxyl group that can be anchored to 4-benzyl chloride-functionalized silica gel, followed by the coordination of palladium(II) chloride. The catalytic activity and the recyclability of Pd-BOX-Si have been investigated in the production of cinnamic acid derivatives via Mizoroki–Heck coupling reactions of acrylates with aryl halides; The Pd-BOX-Si catalyst demonstrated excellent catalytic activity. Characterization of the recycled Pd-BOX-Si catalyst revealed its good stability under the reaction conditions employed. 相似文献