全文获取类型
收费全文 | 181篇 |
免费 | 4篇 |
国内免费 | 3篇 |
专业分类
化学 | 119篇 |
力学 | 4篇 |
数学 | 12篇 |
物理学 | 53篇 |
出版年
2023年 | 2篇 |
2022年 | 2篇 |
2020年 | 6篇 |
2019年 | 4篇 |
2018年 | 4篇 |
2017年 | 4篇 |
2015年 | 5篇 |
2014年 | 5篇 |
2013年 | 5篇 |
2012年 | 10篇 |
2011年 | 8篇 |
2010年 | 4篇 |
2009年 | 4篇 |
2008年 | 8篇 |
2007年 | 10篇 |
2006年 | 6篇 |
2005年 | 10篇 |
2004年 | 8篇 |
2003年 | 7篇 |
2002年 | 6篇 |
2001年 | 5篇 |
2000年 | 5篇 |
1999年 | 3篇 |
1998年 | 2篇 |
1996年 | 2篇 |
1994年 | 2篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 2篇 |
1989年 | 3篇 |
1987年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 4篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 1篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1976年 | 3篇 |
1975年 | 2篇 |
1974年 | 1篇 |
1973年 | 1篇 |
1972年 | 2篇 |
1969年 | 2篇 |
1968年 | 1篇 |
1967年 | 2篇 |
1966年 | 1篇 |
排序方式: 共有188条查询结果,搜索用时 15 毫秒
71.
Colletodiol and 6-epi-colletodiol were synthesized from (5S,2E)-5-tetrahydropyranyloxy-2-hexenoic acid and p-toluenesulfonylethyl (4R,5R,7R,2E)-7-hydroxy-4,5-dimethylmethylenedioxy-2-octenoate. 相似文献
72.
Yohei Tsutsui 《Mathematische Nachrichten》2016,289(2-3):360-376
In R 3, a div‐curl lemma with critical exponents in terms of Hardy spaces associated to Herz spaces is given. 相似文献
73.
74.
The structure of rings all of whose ideals are prime is studied and several examples of such rings are constructed. 相似文献
75.
Optical Review - In this report, we propose a ring resonator with one port for surface normal input/output attached with another ring resonator. A resonance generated by one of the ring resonators... 相似文献
76.
Daiki Tanaka Yuya Tsutsui Dr. Akihito Konishi Koichi Nakaoka Dr. Hideto Nakajima Prof. Dr. Akio Baba Dr. Kouji Chiba Prof. Dr. Makoto Yasuda 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(65):15023-15034
Selective bond formations are one of the most important reactions in organic synthesis. In the Lewis acid mediated electrophile reactions of carbonyls, the selective formation of a carbonyl–acid complex plays a critical role in determining selectivity, which is based on the difference in the coordinative interaction between the carbonyl and Lewis acid center. Although this strategy has attained progress in selective bond formations, the discrimination between similarly sized aromatic and aliphatic carbonyls that have no functional anchors to strongly interact with the metal center still remains a challenging issue. Herein, this work focuses on molecular recognition driven by dispersion interactions within some aromatic moieties. A Lewis acid catalyst with a π-space cavity, which is referred to as a π-pocket, as the recognition site for aromatic carbonyls is designed. Cage-shaped borates 1 B with various π-pockets demonstrated significant chemoselectivity for aromatic aldehydes 3 b – f over that of aliphatic 3 a in competitive hetero-Diels–Alder reactions. The effectiveness of our catalysts was also evidenced by intramolecular recognition of the aromatic carbonyl within a dicarbonyl substrate. Mechanistic and theoretical studies demonstrated that the selective activation of aromatic substrates was driven by the preorganization step with a larger dispersion interaction, rather than the rate-determining step of the C−C bond formation, and this was likely to contribute to the preferred activation of aromatic substrates over that of aliphatic ones. 相似文献
77.
Ishii K Tsutsui K Endoh Y Tohyama T Maekawa S Hoesch M Kuzushita K Tsubota M Inami T Mizuki J Murakami Y Yamada K 《Physical review letters》2005,94(20):207003
We report a resonant inelastic x-ray scattering (RIXS) study of charge excitations in the electron-doped high-T(c) superconductor Nd1.85 Ce0.15 CuO4. The intraband and interband excitations across the Fermi energy are separated for the first time by tuning the experimental conditions properly to measure charge excitations at low energy. A dispersion relation with q-dependent width emerges clearly in the intraband excitation, while the intensity of the interband excitation is concentrated around 2 eV near the zone center. The experimental results are consistent with theoretical calculation of the RIXS spectra based on the Hubbard model. 相似文献
78.
Masami Iyo Kosuke Tsutsui Atsushi Kameyama Tadatoimi Nishikubo 《Journal of polymer science. Part A, Polymer chemistry》1999,37(16):3071-3078
Novel polyfunctional (meth)acrylates with a calixarene backbone [calixarene (meth)acrylates] were synthesized in good yields by certain reactions of p-methylcalix[6]arene (1a) or p-tert-butylcalix[6]arene (1b) with (meth)acrylate derivatives such as acryloyl chloride, methacryloyl chloride, (2-methacryloxy)ethyl isocyanate, and glycidyl methacrylate. Polyfunctional acrylate 6a having poly(oxyethylene) spacer chain between 1a and acrylate groups was also synthesized by the reaction of the poly(oxyethylene) modified 1a with acrylic acid. Calixarene acrylate 6a was liquid at room temperature, although the other calixarene (meth)acrylates were solid at room temperature. The initial decomposition temperature (IDT) of the resulting calixarene (meth)acrylates was measured by the thermogravimetric analysis to evaluate the thermal stability, and it was found that some of the IDTs of the calixarene acrylates were over 400°C. This means that calixarene (meth)acrylates have very good thermal stability. The photopolymerization of the resulting some calixarene (meth)acrylates with (2-phenyoxy)ethyl acrylate as a reactive diluent in the presence of photoinitiator proceeded smoothly upon irradiation with UV light. Therefore, polyfunctional (meth)acrylates with a calixarene backbone can be expected to be novel and thermally stable photoreactive acrylate oligomers. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3071–3078, 1999 相似文献
79.
Taira Aida Yusuke Tsutsui Satoshi Kanada Jiro Okada Kazuhide Hayashi Tetsufumi Komukai 《Journal of Solid State Electrochemistry》2017,21(7):2047-2054
LiNi1-x-yCoxMnyO2 (NCM) with excessive lithium is known to exhibit high rate capability and charge–discharge cycling durability. However, the practical usage of NCM is difficult, because the positive electrode slurry is unstable and battery cells swell due to the alkaline residual lithium compound generated on the surface of NCM particles. To reduce the residual lithium compound, ammonium metatungstate (AMT) added to NCM is studied, and the effect is investigated by scanning electron microscopy, aberration-corrected scanning transmission electron microscopy, X-ray diffractometry, synchrotron X-ray diffractometry, and several electrochemical measurements. It is found that the AMT modification reduces the amount of alkaline residual lithium compound and improves the rate capability due to the ~1-nm-thick W-rich layer generated on the NCM surface. 相似文献
80.
The effect of Zn2+ on the O2- generation and change in intracellular Ca2+ concentration ([Ca2+]i) of rat peritoneal neutrophils was studied. Zymosan (serum-treated zymosan (STZ))-induced O2- generation was inhibited by Zn2+ at concentrations as low as 10 microM. A large amount of the inhibition was observed in the absence of extracellular Ca2+ but the inhibition could not be restored by increasing the extracellular Ca2+ concentration, indicating that Zn2+ does not necessarily inhibit the O2- generation competitively with extracellular Ca2+. In the absence of extracellular Ca2+, Zn2+ inhibited STZ-induced transient increase in [Ca2+]i in the concentration range that evoked a marked inhibition in the O2- generation. On the other hand, Zn2+ did not inhibit significantly STZ-induced uptake of 45Ca2+ from extracellular medium by the cells. From these results, it is suggested that Zn2+ inhibits STZ-induced release of Ca2+ from intracellular storage sites, resulting in the suppression of the activation mechanism of neutrophils. 相似文献