全文获取类型
收费全文 | 614篇 |
免费 | 35篇 |
国内免费 | 1篇 |
专业分类
化学 | 526篇 |
晶体学 | 4篇 |
力学 | 2篇 |
数学 | 5篇 |
物理学 | 113篇 |
出版年
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 13篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2016年 | 16篇 |
2015年 | 14篇 |
2014年 | 17篇 |
2013年 | 22篇 |
2012年 | 45篇 |
2011年 | 30篇 |
2010年 | 22篇 |
2009年 | 21篇 |
2008年 | 31篇 |
2007年 | 24篇 |
2006年 | 38篇 |
2005年 | 21篇 |
2004年 | 24篇 |
2003年 | 18篇 |
2002年 | 16篇 |
2001年 | 6篇 |
2000年 | 9篇 |
1999年 | 6篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 4篇 |
1995年 | 7篇 |
1993年 | 10篇 |
1992年 | 7篇 |
1991年 | 13篇 |
1990年 | 7篇 |
1989年 | 6篇 |
1988年 | 5篇 |
1987年 | 11篇 |
1986年 | 11篇 |
1985年 | 21篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 10篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 5篇 |
1978年 | 6篇 |
1977年 | 9篇 |
1976年 | 5篇 |
1974年 | 10篇 |
1973年 | 6篇 |
1972年 | 9篇 |
1968年 | 5篇 |
1967年 | 3篇 |
排序方式: 共有650条查询结果,搜索用时 0 毫秒
1.
2.
3.
Calculations of the effects of amplified spontaneous emission (ASE) in laser amplifiers designed to amplify sub-picosecond pulses are presented. A one-dimensional code is used with some simple approximations to account for aspect ratio variation in cases of cylindrical symmetry. Gain depletion due to ASE is compared for various multi-pass geometries. Optimisation for short pulse amplification of a telescopic, beam-expanding, 4-pass amplifier is considered.On leave from Electrotechnical Laboratory, Tsukuba, Ibaraki, Japan 相似文献
4.
Takanori MiyashitaNoritake Matsumoto Tomohisa MoriguchiKazuo Shinozuka 《Tetrahedron letters》2003,44(40):7399-7402
A novel phosphoramidite synthon of a dinucleoside phosphotriester unit bearing an intercalative moiety at its internucleotide linkage in a stereospecific manner was prepared and successfully incorporated into the middle portion of α-β chimeric oligoDNA. One of the resulting stereoisomeric chimera DNAs strongly enhances the thermal stability of an alternate-stranded triplex formed between the chimera and a double-stranded DNA. 相似文献
5.
Hiroshi Aoki Ken Hosoya Tomohisa Norisuye Nobuo Tanaka Daisuke Tokuda Norio Ishizuka Kazuki Nakanishi 《Journal of polymer science. Part A, Polymer chemistry》2006,44(2):949-958
An investigation was made of the gelation of dimethacrylate‐type crosslinking agents in view of an application for separation media. The study mainly centered on a crosslinking agent, glycerol dimethacrylate (GDMA), which is relatively hydrophilic because of a hydroxyl group in the middle of its structure. The gelation of GDMA was compared with that of other hydrophobic crosslinking agents such as ethylene glycol dimethacrylate and 1,6‐hexanediol dimethacrylate. The diluents used in the study were toluene, toluene with methanol, and cyclohexanol. The gelation was observed in real time with a charge coupled device camera and dynamic light scattering (DLS). Also, the separated dry gels were extensively characterized with scanning electron microscopy, BET (N2 absorption and desorption isotherm), and Fourier transform infrared. DLS analysis showed a stronger molecular interaction of GDMA gelation in toluene, whereas this interaction was much weaker in an alcoholic solvent such as toluene with methanol or cyclohexanol. This indicated that GDMA gelation might proceed through hydrogen bonding as well as a crosslinking reaction of vinyl groups. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 949–958, 2006 相似文献
6.
7.
8.
9.
Dedicated to Professor John C. Sheehan on the occasion of his sixty-fifth birthday. Chemical and biological modifications of bleomycin, an antitumor glycopeptide antibiotic, have been achieved by three procedures analogous to the modifications of penicillin. 相似文献
10.