全文获取类型
收费全文 | 547篇 |
免费 | 11篇 |
国内免费 | 1篇 |
专业分类
化学 | 334篇 |
晶体学 | 11篇 |
力学 | 11篇 |
数学 | 30篇 |
物理学 | 173篇 |
出版年
2023年 | 7篇 |
2022年 | 10篇 |
2021年 | 8篇 |
2020年 | 14篇 |
2019年 | 20篇 |
2018年 | 20篇 |
2017年 | 14篇 |
2016年 | 19篇 |
2015年 | 14篇 |
2014年 | 12篇 |
2013年 | 30篇 |
2012年 | 36篇 |
2011年 | 31篇 |
2010年 | 22篇 |
2009年 | 14篇 |
2008年 | 23篇 |
2007年 | 28篇 |
2006年 | 23篇 |
2005年 | 19篇 |
2004年 | 14篇 |
2003年 | 10篇 |
2002年 | 9篇 |
2000年 | 3篇 |
1999年 | 8篇 |
1998年 | 10篇 |
1997年 | 5篇 |
1996年 | 4篇 |
1995年 | 5篇 |
1994年 | 8篇 |
1993年 | 5篇 |
1992年 | 6篇 |
1991年 | 4篇 |
1990年 | 5篇 |
1988年 | 7篇 |
1987年 | 4篇 |
1986年 | 5篇 |
1985年 | 9篇 |
1984年 | 13篇 |
1983年 | 6篇 |
1981年 | 12篇 |
1980年 | 4篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 6篇 |
1974年 | 3篇 |
1973年 | 4篇 |
1972年 | 2篇 |
1971年 | 5篇 |
1955年 | 2篇 |
1954年 | 2篇 |
排序方式: 共有559条查询结果,搜索用时 15 毫秒
451.
452.
K. Venkatesh Sumit Chhillar Granthali S. Kamble Shailaja P. Pandey Manisha Venkatesh Sanjukta A. Kumar Sanjiv Kumar R. Acharya P. K. Pujari A. V. R. Reddy 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(3):1425-1428
Boron is an important element in nuclear technology. A comparative study was carried out for the determination of boron in borosilicate glass, boron carbide and graphite samples by wet-chemical and nuclear analytical methods. Wet chemical methods namely titrimetry, Inductively Coupled Plasma Mass Spectrometry and ICP Optical Emission Spectrometry and nuclear analytical methods namely Particle Induced Gamma-Ray Emission and Nuclear Reaction Analysis were used. Boron concentrations were in trace (mg kg?1) level in graphite and percentage level in borosilicate glass and boron carbide. 相似文献
453.
454.
455.
456.
Sumit S. Bhosale 《合成通讯》2013,43(12):1411-1420
Aromatic and heteroaromatic aldehydes are efficiently reduced to their corresponding alcohols in the presence of [RuCl2(p-cymene)]2 and KOAc in 2-propanol under air at 80 °C. The presence of KOAc in the reaction is essential; in its absence no reduction takes place. A highly efficient, external-base-free reduction of aldehydes has also been reported with (η6-arene)ruthenium(II) complexes containing O^O chelate ligand such as [Ru(OAc)2(p-cymene)] and [RuCl(KA)(p-cymene)], obtaining alcohol in excellent yield (OAc, acetate; KA, kojic acetate). The scope of the reaction has been extended to a broad range of aromatic and heteroaromatic aldehydes. 相似文献
457.
A novel and efficient method for the synthesis of a new variety of methylsulfanylpyrimidines by the reaction of dimethyl N‐cyanodithioiminocarbonate with substituted hydrazides. The synthetic potential of the method is demonstrated. 相似文献
458.
The formation of new C-C bond through highly regioselective ring opening of chalcone epoxides to nitrogen-containing heterocycles has been effectively worked out in impressive yields with heterocyclic nucleophiles such as pyrrole, indole, and 2-methyl indole in the presence of β-cyclodextrin using water as solvent at room temperature within 25–50 min. Water, an environmentally friendly reaction medium, has been utilized for the first time for the reaction of these heterocyclic nucleophiles with chalcone epoxides as their β-cyclodextrin complexes to afford 1,3-diaryl-2-hydroxy-3-(1H-3-indolyl/2-pyrrolyl)propan-1-ones (3a–u). The catalyst can be easily recovered and recycled for several times without loss of activity. 相似文献
459.
Kumar Ajay Vij Raman Sharma Sumit Sarin Amit 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):495-506
In this investigation, the passive estimation of radon (Rn222), thoron (Rn220) and their progenies have been measured in the dwellings of Reasi district of Jammu & Kashmir for a period of 1 year. These estimations have been done with the help of latest developed single entry Pin-hole based dosimeters and progeny sensors based on deposition. The annual Equilibrium factors for 222Rn, 220Rn, and their progenies have been calculated separately for each dwellings The average annual effective dose was found to be 0.9 ± 0.2 mSv/y for 222Rn, which is less than prescribed limit of ICRP. The results obtained indicate no vital health hazards because of exposure of Rn222, Rn220 and their progenies.
相似文献460.