全文获取类型
收费全文 | 1780篇 |
免费 | 40篇 |
国内免费 | 14篇 |
专业分类
化学 | 1389篇 |
晶体学 | 20篇 |
力学 | 12篇 |
数学 | 52篇 |
物理学 | 361篇 |
出版年
2021年 | 19篇 |
2020年 | 11篇 |
2019年 | 26篇 |
2018年 | 17篇 |
2017年 | 10篇 |
2016年 | 21篇 |
2015年 | 25篇 |
2014年 | 31篇 |
2013年 | 90篇 |
2012年 | 70篇 |
2011年 | 102篇 |
2010年 | 57篇 |
2009年 | 45篇 |
2008年 | 106篇 |
2007年 | 93篇 |
2006年 | 88篇 |
2005年 | 85篇 |
2004年 | 80篇 |
2003年 | 64篇 |
2002年 | 63篇 |
2001年 | 46篇 |
2000年 | 50篇 |
1999年 | 41篇 |
1998年 | 21篇 |
1997年 | 20篇 |
1996年 | 29篇 |
1995年 | 32篇 |
1994年 | 20篇 |
1993年 | 12篇 |
1992年 | 25篇 |
1991年 | 26篇 |
1990年 | 19篇 |
1989年 | 20篇 |
1988年 | 15篇 |
1987年 | 22篇 |
1986年 | 26篇 |
1985年 | 49篇 |
1984年 | 38篇 |
1983年 | 17篇 |
1982年 | 18篇 |
1981年 | 10篇 |
1980年 | 16篇 |
1979年 | 24篇 |
1978年 | 26篇 |
1977年 | 15篇 |
1976年 | 15篇 |
1975年 | 13篇 |
1974年 | 14篇 |
1973年 | 9篇 |
1971年 | 10篇 |
排序方式: 共有1834条查询结果,搜索用时 15 毫秒
151.
152.
153.
Y. Hashimoto L. Matsuoka D. NagamotoS. Hasegawa 《Spectrochimica Acta Part B: Atomic Spectroscopy》2008
We developed an ion trap — laser cooling system for observing the laser induced fluorescence (LIF) of a single ion, in the view of utilizing it for the trace isotope analysis of Ca. We observed stepwise LIF signals, which correspond to the numbers of trapped 40Ca+ ions (40Ca/Ca = 96.9%). The detection efficiency was evaluated and the observation of single ions demonstrated the experimental feasibility of trace isotope analysis. Furthermore, as the next step towards trace isotope analysis, we report observation of the even calcium isotopes, 44Ca (44Ca/Ca = 2.09%) and 48Ca (48Ca/Ca = 0.187%), without the use of a selective loading method. 相似文献
154.
155.
156.
Tamio Kamidate Yasunori Hashimoto Hirofumi Tani Akihiko Ishida 《Analytical sciences》2002,18(3):273-276
The uptake of Cu2+ was investigated using various types of liposomes composed of phosphatidylcholine (PC), cholesterol (Chol) and dicethylphosphate (DCP). DCP played a role as a ligand for Cu2+. Multilamellar vesicles (MLVs) were more effective for the uptake of Cu2+ compared to unilamellar vesicles prepared by the extrusion technique. The uptake efficiency of MLVs for Cu2+ was dependent on the molar ratio of DCP in MLVs. The uptake percent of Cu2+ was 92% using MLVs having a PC:DCP:Chol molar ratio of 4:3:3; 95% of the total vesicle Cu2+ was bound to DCP of the outer membrane surface of the MLVs, and the remaining 5% of the total Cu2+ was distributed into the interior side of the MLVs. MLVs having a PC:DCP:Chol molar ratio of 4:3:3 were also effective as separation media for Mn2+, Co2+, Ni2+ and Zn2+. The uptake efficiency of the MLVs for the transition-metal ions increased in the order Co2+ < Zn2+ < Ni2+ < Mn2+ < Cu2+. 相似文献
157.
158.
159.
Tamotsu Hashimoto Yusuke Makino Michio Urushisaki Toshikazu Sakaguchi 《Journal of polymer science. Part A, Polymer chemistry》2008,46(5):1629-1637
Living cationic polymerization of 2‐adamantyl vinyl ether (2‐vinyloxytricyclo[3.3.1.1]3,7decane; 2‐AdVE) was achieved with the CH3CH(OiBu)OCOCH3/ethylaluminum sesquichloride/ethyl acetate [CH3CH(OiBu)OCOCH3/Et1.5AlCl1.5/CH3COOEt] initiating system in toluene at 0 °C. The number‐average molecular weights (Mn's) of the obtained poly(2‐AdVE)s increased in direct proportion to monomer conversion and produced the polymers with narrow molecular weight distributions (MWDs) (Mw/Mn = ~1.1). When a second monomer feed was added to the almost polymerized reaction mixture, the added monomer was completely consumed and the Mn's of the polymers showed a direct increase against conversion of the added monomer. Block and statistical copolymerization of 2‐AdVE with n‐butyl vinyl ether (CH2?CH? O? CH2 CH2CH2CH3; NBVE) were possible via living process based on the same initiating system to give the corresponding copolymers with narrow MWDs. Grass transition temperature (Tg) and thermal decomposition temperature (Td) of the poly(2‐AdVE) (e.g., Mn = 22,000, Mw/Mn = 1.17) were 178 and 323 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1629–1637, 2008 相似文献
160.