全文获取类型
收费全文 | 457篇 |
免费 | 23篇 |
国内免费 | 3篇 |
专业分类
化学 | 364篇 |
晶体学 | 3篇 |
力学 | 10篇 |
数学 | 23篇 |
物理学 | 83篇 |
出版年
2023年 | 3篇 |
2021年 | 10篇 |
2020年 | 17篇 |
2019年 | 11篇 |
2018年 | 6篇 |
2017年 | 4篇 |
2016年 | 8篇 |
2015年 | 14篇 |
2014年 | 11篇 |
2013年 | 16篇 |
2012年 | 31篇 |
2011年 | 35篇 |
2010年 | 24篇 |
2009年 | 18篇 |
2008年 | 34篇 |
2007年 | 25篇 |
2006年 | 23篇 |
2005年 | 21篇 |
2004年 | 35篇 |
2003年 | 25篇 |
2002年 | 22篇 |
2001年 | 12篇 |
2000年 | 4篇 |
1999年 | 6篇 |
1997年 | 2篇 |
1996年 | 8篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1991年 | 4篇 |
1990年 | 4篇 |
1989年 | 3篇 |
1987年 | 2篇 |
1986年 | 1篇 |
1985年 | 2篇 |
1984年 | 3篇 |
1982年 | 4篇 |
1981年 | 2篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 2篇 |
1973年 | 1篇 |
1971年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
1965年 | 1篇 |
1964年 | 1篇 |
1963年 | 2篇 |
排序方式: 共有483条查询结果,搜索用时 0 毫秒
481.
Natsumi Fukushi Miku Yoshizawa Shota Onosato Motohiro Hanada Wataru Takarada 《Journal of Macromolecular Science: Physics》2018,57(2):110-128
Multiple melting behavior of high-speed melt-spun polylactide (PLA) fibers was investigated by temperature modulated differential scanning calorimetry (TMDSC) in the heating process with various modulation periods in the calorimeter. In the case of the as-spun PLA fibers taken-up at 1 km/min, a melting endothermic peak and a recrystallization exothermic peak appeared at the same peak temperature of 151°C in the reversing and non-reversing heat flows (RHF and NRHF), respectively, whereas at 168°C, an endothermic peak was observed in both the RHF and NRHF. On the other hand, the as-spun PLA fibers taken-up at a high-speed of 6 km/min showed the melting in both the RHF and NRHF, but the recrystallization behavior was not obvious in the NRHF at the shorter modulation period conditions. The obtained data were analyzed based on the kinetic modeling of melting proposed by Toda et al. The real and imaginary parts of the complex apparent heat capacity in the melting region showed a strong modulation period dependence for both the low- and high-speed spun fibers. The endothermic heat flow of melting was separated by extrapolating the frequency to zero. For the PLA fibers spun at 1 km/min, a set of melting and recrystallization peaks in the RHF and NRHF appeared even for the melting at 168°C. In other words, the simultaneous occurrence of melting and recrystallization was confirmed through this extrapolation. For the 6 km/min PLA fibers, the presence of an exothermic heat of recrystallization was clearly confirmed at a peak temperature of 164°C. 相似文献
482.
Erin M. Hanada Patrick J. McShea Prof. Suzanne A. Blum 《Angewandte Chemie (International ed. in English)》2023,62(43):e202307787
Trimethylsilyl chloride (TMSCl) is commonly used to “activate” metal(0) powders toward oxidative addition of organohalides, but knowledge of its mechanism remains limited by the inability to characterize chemical intermediates under reaction conditions. Here, fluorescence lifetime imaging microscopy (FLIM) overcomes these prior limitations and shows that TMSCl aids in solubilization of the organozinc intermediate from zinc(0) metal after oxidative addition, a previously unknown mechanistic role. This mechanistic role is in contrast to previously known roles for TMSCl before the oxidative addition step. To achieve this understanding, FLIM, a tool traditionally used in biology, is developed to characterize intermediates during a chemical reaction—thus revealing mechanistic steps that are unobservable without fluorescence lifetime data. These findings impact organometallic reagent synthesis and catalysis by providing a previously uncharacterized mechanistic role for a widely used activating agent, an understanding of which is suitable for revising activation models and for developing strategies to activate currently unreactive metals. 相似文献
483.
Dr. Wataru Kosaka Yoshie Hiwatashi Naoka Amamizu Prof. Dr. Yasutaka Kitagawa Prof. Dr. Jun Zhang Prof. Dr. Hitoshi Miyasaka 《Angewandte Chemie (International ed. in English)》2023,62(48):e202312205
Partial charge fluctuations in the charge-ordered state of a material, often triggered by structural disorders and/or defects, can significantly alter its physical characteristics, such as magnetic long-range ordering. However, it is difficult to post-chemically fix such accidental partial fluctuations to reconstruct a uniform charge-ordered state. Herein, we report CO2-aided charge ordering demonstrated in a CO2-post-captured layered magnet, [{Ru2(o-ClPhCO2)4}2{TCNQ(OMe)2}] ⋅ CO2 ( 1⊃CO2 ; o-ClPhCO2−=ortho-chlorobenzoate; TNCQ(OMe)2=2,5-dimethoxy-7,7,8,8-tetracyanoquinodimethane). Pristine porous layered magnet 1 had a partially charge-fluctuated ordered state, which provided ferrimagnetic ordering at TC=65 K. Upon loading CO2, 1 adsorbed one mole of CO2, forming 1⊃CO2 , and raising TC to 100 K. This was because of the vanishing charge fluctuations without significantly changing the framework structure. This research illustrates the post-accessible host–guest chemistry delicately combined with charge, spin, and lattice ordering in a spongy magnet. Furthermore, it highlights how this innovative approach opens up new possibilities for technology and nanoscale magnetism manipulation. 相似文献