全文获取类型
收费全文 | 8703篇 |
免费 | 927篇 |
国内免费 | 687篇 |
专业分类
化学 | 2645篇 |
晶体学 | 61篇 |
力学 | 625篇 |
综合类 | 52篇 |
数学 | 841篇 |
物理学 | 6093篇 |
出版年
2024年 | 28篇 |
2023年 | 91篇 |
2022年 | 131篇 |
2021年 | 112篇 |
2020年 | 195篇 |
2019年 | 169篇 |
2018年 | 173篇 |
2017年 | 235篇 |
2016年 | 318篇 |
2015年 | 276篇 |
2014年 | 488篇 |
2013年 | 816篇 |
2012年 | 414篇 |
2011年 | 726篇 |
2010年 | 508篇 |
2009年 | 619篇 |
2008年 | 607篇 |
2007年 | 600篇 |
2006年 | 510篇 |
2005年 | 375篇 |
2004年 | 349篇 |
2003年 | 333篇 |
2002年 | 317篇 |
2001年 | 272篇 |
2000年 | 296篇 |
1999年 | 208篇 |
1998年 | 192篇 |
1997年 | 136篇 |
1996年 | 103篇 |
1995年 | 119篇 |
1994年 | 84篇 |
1993年 | 84篇 |
1992年 | 80篇 |
1991年 | 50篇 |
1990年 | 39篇 |
1989年 | 60篇 |
1988年 | 38篇 |
1987年 | 31篇 |
1986年 | 19篇 |
1985年 | 19篇 |
1984年 | 22篇 |
1983年 | 10篇 |
1982年 | 11篇 |
1981年 | 10篇 |
1980年 | 8篇 |
1979年 | 6篇 |
1978年 | 5篇 |
1977年 | 4篇 |
1976年 | 6篇 |
1973年 | 8篇 |
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
191.
192.
The solid-liquid equilibrium diagrams of binary mixtures involving magnesium nitrate hexahydrate with cobalt nitrate hexahydrate, nickel nitrate hexahydrate (partly), manganese nitrate tetrahydrate, and iron(III) nitrate nonahydrate and of magnesium chloride hexahydrate with cobalt and nickel chlorides hexahydrates and manganese chloride tetrahydrate, and the of two manganese salts were determined. Those diagrams that showed a simple eutectic were fitted by the Ott equation and where the required BET parameters were available, the magnesium salt rich parts of the liquidus were modeled by means of this method. 相似文献
193.
194.
Joachim Angelkort Sander van Smaalen Prof. Dr. Sven Oliver Hauber Mark Niemeyer 《无机化学与普通化学杂志》2007,633(7):1031-1035
Single crystal X‐ray diffraction of Eu(SC36H49)2 has revealed a first order phase transition at a temperature of 119 K, that involves a reduction of the specific volume by 1 %. The transition corresponds to a doubling of the unit cell, as it is the result from reorientations of isopropyl groups that appear at peripheral sites of the organic ligands. It is argued that a denser packing is achieved at the expense of a less favourable conformation of one of the two crystallographically‐independent complexes in the low‐temperature phase. The Bond‐Valence method is used to show that interactions of equal strengths are present between europium and both sulphur atoms and both coordinating phenyl rings. 相似文献
195.
Cr(Ⅲ)—5—Br—PADAP—Triton X—100析相光度法测定微量铬的研究 总被引:1,自引:0,他引:1
研究Cr(Ⅲ)-5-Br-PADAP-Triton X-100析相显色体系,建立测定微量铬的析相光度法。在pH 4.5乙酸-乙酸钠介质中,Cr(Ⅲ)、5-Br-PADAP、Triton X-100加热形成的配合物,于95℃恒温浴中析相1h,即被Triton X-100相完全富集,最大吸收峰为593nm,铬含量在0~10μg/5ml服从比耳定律,以硫脲、锰-EDTA、柠檬酸钠、氟化钾为掩蔽剂,测定水样中微量铬,获得满意结果。 相似文献
196.
197.
198.
A general thermodynamic equation for the swelling of a cross-linked polymer system in the vapour of a swelling agent has been derived under isothermal and isobaric conditions. The equation is used to describe the equilibrium uptake of water by elastomers Arnitel® (DSM), which are hard-soft-segment block copolymers in which the hard segments poly(butylene terephthalate) crystallise and are responsible for a physical cross-linking. The gravimetrically determined degrees of swelling of different elastomers in water vapour of various partial pressures are analysed and discussed by the application of an extended semi-empirical swelling equation of Flory-Huggins-Staverman-van Santen. 相似文献
199.
The crystalline morphology of a thermotropic aromatic polyester has been studied by microscopy techniques. Spherulites with ringed structure under polarizing micioscope were observed for solution cast specimens, They were composed of radially growing crystalline lamellae of thickness around 100. It was found that the molecules were packed in the thickness direction. Banded texture was observed in randomly packed domains for melt cast specimens. The bands have the same width and internal structure as those usually observed in oriented specimens of these polymers obtained by shearing their mesomorphic melt. 相似文献
200.
Jin Ling CHAI Yan Hong GAO Kong Shuang ZHAO Gan Zuo LI Gao Yong ZHANG 《中国化学快报》2005,16(9):1263-1266
The dielectric relaxation spectroscopy (DRS) of Winsor I -Ⅲ microemulsions for nonionic surfactant octyl polyglucoside CsG1.46/1-butanol/cyclohexanedwater system was studied. The experiment shows that the permittivity decreases with the increase in the frequency and clear dielectric relaxation phenomena were observed. Permittivity obviously decreases with the change of the microstructure of the microemulsion, W/O, B.C. and O/W can be distinguished by the permittivity. 相似文献