全文获取类型
收费全文 | 265篇 |
免费 | 9篇 |
国内免费 | 1篇 |
专业分类
化学 | 239篇 |
晶体学 | 1篇 |
力学 | 5篇 |
数学 | 3篇 |
物理学 | 27篇 |
出版年
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2018年 | 2篇 |
2017年 | 1篇 |
2016年 | 5篇 |
2015年 | 3篇 |
2014年 | 6篇 |
2013年 | 16篇 |
2012年 | 12篇 |
2011年 | 13篇 |
2010年 | 6篇 |
2009年 | 11篇 |
2008年 | 11篇 |
2007年 | 13篇 |
2006年 | 14篇 |
2005年 | 10篇 |
2004年 | 10篇 |
2003年 | 13篇 |
2002年 | 7篇 |
2001年 | 2篇 |
2000年 | 9篇 |
1999年 | 4篇 |
1998年 | 7篇 |
1997年 | 7篇 |
1996年 | 1篇 |
1995年 | 3篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 1篇 |
1990年 | 4篇 |
1989年 | 6篇 |
1988年 | 7篇 |
1987年 | 1篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 8篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 7篇 |
1980年 | 2篇 |
1979年 | 4篇 |
1978年 | 3篇 |
1975年 | 2篇 |
1974年 | 3篇 |
1973年 | 7篇 |
1972年 | 1篇 |
排序方式: 共有275条查询结果,搜索用时 0 毫秒
271.
Bis(isopropylxanthogen) disulfide (BX) has been used as a photoinitiator with various vinyl monomers at 30°C. The kinetics of polymerization of styrene (St) and methyl methacrylate (MMA) at 30°C were studied for various concentrations of monomer and initiator. The observed deviations in polymerization rate from simple kinetic theory could be explained in terms of primary radical termination. The fraction of primary radical terminating chains was obtained as a function of various concentrations. The ratio of the rate constants for chain initiation and chain termination by a primary radical was determined to be 3.34 ± 107 for St and 2.60 ± 107 for MMA. The number-average degree of polymerization (DP n) of polymers obtained by photopolym-erization with BX was found to increase linearly with conversion. However, the DP n extrapolated to zero conversion was in good agreement with that calculated on the basis of the kinetic scheme. It was found that BX had interesting properties for the design of block copolymers, i.e., BX acts as a terminator and a chain transfer agent as well as an initiator in these polymerizations. The polymers obtained with BX contained two reactive isopropyl xanthate groups bonded at their chain ends, which could also act as macrophotoinitiators. 相似文献
272.
The authors have developed an asymmetric hollow‐fiber membrane with a skin layer on the outer surface using a dry/wet phase inversion process with a newly synthesized aromatic fluorinated polyamide. Because the skin layer is ultrathin and has no defects, the membrane has gas selectivity in addition to higher gas flux. The membrane has excellent hemocompatibility, which is probably related to packing density of the skin layer. Authors are now clarifying the mechanism of the microstructure formation of the membrane relating to spinning conditions by the standing point of polymer physics. Generally, the microstructure of a polymeric membrane prepared by a phase inversion process is discussed using the phase diagram of the system. However, the process is so dynamic that conventional discussion based on the start and end points is not sufficient, but which path is to be chosen on the phase diagram is more important. 相似文献
273.
Hao K. Shen Kiyoshi Morishita Dr. P. K. Hashim Prof. Dr. Kou Okuro Daiki Kashiwagi Ayumi Kimura Dr. Haruaki Yanagisawa Prof. Dr. Masahide Kikkawa Prof. Dr. Tatsuya Niwa Prof. Dr. Hideki Taguchi Prof. Dr. Takuzo Aida 《Angewandte Chemie (International ed. in English)》2023,62(31):e202304894
Herein, we report an ATP-responsive nanoparticle (GroELNP) whose surface is fully covered with the biomolecular machine “chaperonin protein GroEL”. GroELNP was synthesized by DNA hybridization between a gold NP with DNA strands on its surface and GroEL carrying complementary DNA strands at its apical domains. The unique structure of GroELNP was visualized by transmission electron microscopy including under cryogenic conditions. The immobilized GroEL units retain their machine-like function and enable GroELNP to capture denatured green fluorescent protein and release it in response to ATP. Interestingly, the ATPase activity of GroELNP per GroEL was 4.8 and 4.0 times greater than those of precursor cysGroEL and its DNA-functionalized analogue, respectively. Finally, we confirmed that GroELNP could be iteratively extended to double-layered NP. 相似文献
274.
275.
Akinori Takasu Terumi Niwa Hisashi Itou Yoshihito Inai Tadamichi Hirabayashi 《Macromolecular rapid communications》2000,21(11):764-769
A new procedure for chemical modification of poly(vinyl alcohol) (PVA) was established by a glycosidation reaction of hydroxyl groups in PVA with triacetylated sugar oxazoline 1 . 1H and 13C NMR analyses indicated that triacetylated N‐acetyl‐D‐glucosamine (GlcNAc) was introduced onto a PVA backbone selectively via a β‐O‐glycoside linkage. Deacetylation of triacetylated GlcNAc‐substituted PVA 2 resulted in GlcNAc‐substituted PVA 3 in good yield. These modified PVAs 2 and 3 exhibited solubilities and thermal properties different from the original PVA. 相似文献