全文获取类型
收费全文 | 8371篇 |
免费 | 313篇 |
国内免费 | 47篇 |
专业分类
化学 | 5479篇 |
晶体学 | 52篇 |
力学 | 255篇 |
数学 | 1485篇 |
物理学 | 1460篇 |
出版年
2023年 | 44篇 |
2022年 | 80篇 |
2021年 | 133篇 |
2020年 | 140篇 |
2019年 | 156篇 |
2018年 | 161篇 |
2017年 | 153篇 |
2016年 | 255篇 |
2015年 | 257篇 |
2014年 | 252篇 |
2013年 | 528篇 |
2012年 | 595篇 |
2011年 | 640篇 |
2010年 | 372篇 |
2009年 | 328篇 |
2008年 | 481篇 |
2007年 | 466篇 |
2006年 | 428篇 |
2005年 | 397篇 |
2004年 | 345篇 |
2003年 | 307篇 |
2002年 | 244篇 |
2001年 | 143篇 |
2000年 | 120篇 |
1999年 | 93篇 |
1998年 | 74篇 |
1997年 | 67篇 |
1996年 | 69篇 |
1995年 | 54篇 |
1994年 | 65篇 |
1993年 | 75篇 |
1992年 | 57篇 |
1991年 | 69篇 |
1990年 | 65篇 |
1989年 | 59篇 |
1988年 | 50篇 |
1987年 | 40篇 |
1985年 | 54篇 |
1984年 | 72篇 |
1983年 | 37篇 |
1982年 | 56篇 |
1981年 | 45篇 |
1980年 | 48篇 |
1979年 | 40篇 |
1978年 | 38篇 |
1977年 | 53篇 |
1976年 | 39篇 |
1975年 | 39篇 |
1974年 | 35篇 |
1973年 | 32篇 |
排序方式: 共有8731条查询结果,搜索用时 15 毫秒
991.
992.
In this study, the effect of ascorbic acid in the electrochemical behavior of copper has been investigated in 3.5 % NaCl solution using potentiodynamic polarization and electrochemical impedance spectroscopy. Current-potential curve and Nyquist diagrams were obtained in different concentrations of ascorbic acid. The surface morphology of copper after its exposure to 3.5 % NaCl solution with and without of ascorbic acid was examined by scanning electron microscopy. The obtained results show that ascorbic acid inhibits corrosion of copper in 3.5 % NaCl solution. The inhibition activity of ascorbic acid increases with a decrease in the concentration of ascorbic acid. 相似文献
993.
994.
The uptake of H2S has been determined for Al2O3 supported Mo, RuMo and PdMo catalysts, exposed previously to cyclohexanol, cyclohexene or thiophene. The amounts of H2S-uptake were compared with those taken up by catalysts treated with H2S only. Significant differences were found in behavior of the different and differently treated catalysts with respect to their sulfur uptake. 相似文献
995.
By weakening the counit and antipode axioms of aC
*-Hopf algebra and allowing for the coassociative coproduct to be nonunital, we obtain a quantum group, that we call aweak C
*-Hopf algebra, which is sufficiently general to describe the symmetries of essentially arbitrary fusion rules. This amounts to generalizing the Baaj-Skandalis multiplicative unitaries to multipicative partial isometries. Every finite-dimensional weakC
*-Hopf algebra has a dual which is again a weakC
*-Hopf algebra. An explicit example is presented with Lee-Yang fusion rules. We briefly discuss applications to amalgamated crossed products, doubles, and quantum chains.Supported by the Hungarian Scientific Research Fund, OTKA T 016 233.Supported by the Hungarian Scientific Research Fund, OTKA-1815. 相似文献
996.
本文揭示了钠、钾受基体元素碲干扰的现象和分析系统中酸度对钠、钾吸光度的影响,在理论上探讨了碲对钠、钾干扰的原因,利用加入盐酸和铝元素的方法分别排除碲对钾、钠的干扰,提出一个方便,实用的测定方法,回收率和RSD分别为95-102%和7.4%。 相似文献
997.
Noël Lohoue 《Annals of Global Analysis and Geometry》1998,16(6):543-571
We give a sufficient condition for stability around 2 of Lp cohomology of a system over locally symmetric space. 相似文献
998.
999.
Translated from Sibirskii Matematicheskii, Vol. 36, No. 1, pp. 164–176, January–February, 1995. 相似文献
1000.
We extend the Gustavsson–Peetre method to the context of N ‐tuples of Banach spaces. We give estimates for the norm of the interpolated operator. The method is applied to tuples of weighted L p ‐spaces and to tuples of Orlicz spaces identifying the outcoming spaces in both cases. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献