全文获取类型
收费全文 | 4475篇 |
免费 | 681篇 |
国内免费 | 625篇 |
专业分类
化学 | 3665篇 |
晶体学 | 38篇 |
力学 | 262篇 |
综合类 | 63篇 |
数学 | 615篇 |
物理学 | 1138篇 |
出版年
2024年 | 2篇 |
2023年 | 62篇 |
2022年 | 69篇 |
2021年 | 91篇 |
2020年 | 140篇 |
2019年 | 151篇 |
2018年 | 133篇 |
2017年 | 117篇 |
2016年 | 216篇 |
2015年 | 197篇 |
2014年 | 276篇 |
2013年 | 350篇 |
2012年 | 389篇 |
2011年 | 344篇 |
2010年 | 321篇 |
2009年 | 277篇 |
2008年 | 284篇 |
2007年 | 253篇 |
2006年 | 258篇 |
2005年 | 205篇 |
2004年 | 191篇 |
2003年 | 188篇 |
2002年 | 299篇 |
2001年 | 256篇 |
2000年 | 138篇 |
1999年 | 118篇 |
1998年 | 86篇 |
1997年 | 50篇 |
1996年 | 46篇 |
1995年 | 38篇 |
1994年 | 45篇 |
1993年 | 11篇 |
1992年 | 17篇 |
1991年 | 28篇 |
1990年 | 25篇 |
1989年 | 18篇 |
1988年 | 16篇 |
1987年 | 16篇 |
1986年 | 11篇 |
1985年 | 11篇 |
1984年 | 9篇 |
1982年 | 5篇 |
1981年 | 4篇 |
1980年 | 7篇 |
1979年 | 4篇 |
1977年 | 3篇 |
1975年 | 1篇 |
1974年 | 1篇 |
1972年 | 2篇 |
1971年 | 1篇 |
排序方式: 共有5781条查询结果,搜索用时 15 毫秒
91.
92.
93.
PengWANG ShuRenJIANG ZhiQiangZHOU 《中国化学快报》2004,15(12):1457-1460
Cellulose-tris(3,5-dimethylphenylcarbamate)(CDMPC) were synthesized as highperformance liquid chromatography (HPLC) chiral stationary phase(CSP). The successful resolution of four chiral pesticides on the CSP was realized and the influence of the temperature on the separation was studied. 相似文献
94.
Shu Ping XU* Huan Wen CHEN Ai Min YU Qin Han JIN Hua Ying LIAO Changchun R&D Center for Analytical Instruments Department of Chemistry Jilin University Changchun Key Laboratory for Supramolecular Structure Spectroscopy of Ministr 《中国化学快报》2002,13(7):660-661
In recent years, the determination of Cr (VI) has attracted great attention because of its toxicity to human, plants and animals1-5. Usually, in the industrial waste water, the concentration of Cr (VI) is relatively high and should be determined frequently. So, an accurate, quick, and convenient method for the measurement of Cr (VI) in environmental water, as well as in river, lake, sea and tap water, is of great importance. The method for determination of Cr (VI) by diphenylcarbazine … 相似文献
95.
Shu Jiang ZHANG Yan Feng LI Xiao Long WANG Da Xue YIN Yu SHAO Xin ZHAO 《中国化学快报》2005,16(9):1165-1168
A new aromatic diamine monomer containing pyridine unit, 2,6-bis (4-aminophenoxy- 4'-benzoyl)pyridine(BABP), was synthesized in three steps, starting from 2,6-pyridinedicarboxyl chloride. A series of novel pyridine-containing polyimides were prepared v/a the polycondensation of BABP with various aromatic dianhydrides through poly(amic acid) precursors, and thermal or chemical imidization of the precursors. The polyimides exhibit desirable properties, e.g., good solubility in N-methyl-2-pyrrolidone and m-cresol, excellent thermal stability and film-forming capability, as well as high inherent viscosity, indicating high molecular weight. 相似文献
96.
Xiao Ling WANG Wei JIAO Xun LIAO Shu Ling PENG Li Sheng DING 《中国化学快报》2006,17(7):916-918
The roots of Paeonia lactiflora Pall. is one of the most important traditional Chinese medicines, which has been used for the treatment of dizziness, spasm, menstrual disorder, spontaneous and night sweating, and as a general analgesic1. Chemical constitu… 相似文献
97.
98.
Wang TT Chung SM Wu FI Shu CF Diau EW 《The journal of physical chemistry. B》2005,109(50):23827-23835
We performed time-resolved spectral investigations of two distyrylcarbazole derivatives, 2,7- and 3,6-distyrylcarbazole (2,7-DPVTCz and 3,6-DPVTCz, respectively), in dilute toluene solution and in solid films mixed with poly(methyl methacrylate) (PMMA). The lifetime of 2,7-DPVTCz in its excited state in solution is approximately 100 times as great as that of 3,6-DPVTCz, consistent with their photophysical nature. The former shows intense emission, but the latter is nearly nonfluorescent in a free environment. Moreover, the lifetime of 3,6-DPVTCz in its excited state increased also approximately 100 times when the molecule was encapsulated in a 3,6-DPVTCz/PMMA solid film, indicating that intramolecular motion of the molecule significantly affects the observed relaxation dynamics in a confined environment. Calculations on the excited states indicate that an efficient intersystem crossing is activated upon twisting of the bridged C-C single bond in a free 3,6-linked carbazole; such efficient deactivation is impractical in 2,7-linked carbazole or for 3,6-linked carbazole in a PMMA matrix. Information obtained from experiments on femtosecond fluorescence enables us to distinguish crucial relaxation processes in the excited state for a profound understanding of the details of vibrational and electronic relaxations of 3,6-DPVTCz in solution. 相似文献
99.
Jun Zhao Shu Hong Guan Xiao Bin Chen Wei Wang Min Ye De An Guo 《中国化学快报》2007,18(11):1316-1318
The biotransformation of bufalin by cell suspension cultures of Platycodon grandiflorus was investigated and two new biotransformed products were obtained,which was 3-epi-telocinobufagin and 3-epi-bufalin-3-O-β-D-glucoside. 相似文献
100.
Fuzzy Optimization and Decision Making - In this paper, an uncertain nonlinear switched system is a nonlinear switched system disturbed by subjective uncertainties, which can be illustrated by... 相似文献