全文获取类型
收费全文 | 1359篇 |
免费 | 39篇 |
国内免费 | 3篇 |
专业分类
化学 | 1065篇 |
晶体学 | 10篇 |
力学 | 12篇 |
数学 | 33篇 |
物理学 | 281篇 |
出版年
2023年 | 12篇 |
2022年 | 14篇 |
2021年 | 28篇 |
2020年 | 27篇 |
2019年 | 29篇 |
2018年 | 23篇 |
2017年 | 12篇 |
2016年 | 35篇 |
2015年 | 29篇 |
2014年 | 33篇 |
2013年 | 68篇 |
2012年 | 79篇 |
2011年 | 98篇 |
2010年 | 35篇 |
2009年 | 47篇 |
2008年 | 85篇 |
2007年 | 76篇 |
2006年 | 83篇 |
2005年 | 67篇 |
2004年 | 62篇 |
2003年 | 47篇 |
2002年 | 53篇 |
2001年 | 21篇 |
2000年 | 28篇 |
1999年 | 7篇 |
1998年 | 12篇 |
1997年 | 6篇 |
1996年 | 9篇 |
1995年 | 7篇 |
1994年 | 15篇 |
1993年 | 12篇 |
1992年 | 14篇 |
1991年 | 13篇 |
1990年 | 13篇 |
1989年 | 9篇 |
1988年 | 16篇 |
1987年 | 20篇 |
1986年 | 7篇 |
1985年 | 12篇 |
1984年 | 10篇 |
1983年 | 6篇 |
1982年 | 8篇 |
1981年 | 14篇 |
1980年 | 7篇 |
1979年 | 10篇 |
1978年 | 14篇 |
1977年 | 9篇 |
1976年 | 11篇 |
1974年 | 8篇 |
1973年 | 11篇 |
排序方式: 共有1401条查询结果,搜索用时 15 毫秒
71.
Nobutaka Yoshimura Dr. Atsushi Kobayashi Dr. Masaki Yoshida Prof. Masako Kato 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(70):16939-16946
To investigate the effect of the surface structure of dye-sensitized photocatalyst nanoparticles, we prepared three types of RuII-photosensitizer (PS)-double-layered Pt-cocatalyst-loaded TiO2 nanoparticles with different surface structures, Zr- RuCP6 -Zr- RuP6 @N wt %Pt-TiO2, RuCP6 -Zr- RuP6 @N wt %Pt-TiO2, and RuCP2 -Zr- RuP6 @N wt %Pt-TiO2 (N=0.2, 1, and 5), and evaluated their photocatalytic H2 evolution activity in the presence of redox-reversible iodide as the electron donor. Although the driving force of the electron injection from I− to the photo-oxidized RuIII PS is comparable, the activity increased in the following order: RuCP2 -Zr- RuP6 @1 wt %Pt-TiO2 < RuCP6 -Zr- RuP6 @1 wt %Pt-TiO2 < Zr- RuCP6 -Zr- RuP6 @1 wt %Pt-TiO2. The apparent quantum yield of Zr- RuCP6 -Zr- RuP6 @1 wt %Pt-TiO2 in the first hour reached 1 %. Zeta-potential measurements suggest that the surface Zr4+-phosphate groups attracted I− anions to the nanoparticle–solution interface. Our results indicate that the surface modification of dye-sensitized photocatalysts is a promising approach to enhance photocatalytic activity with various redox mediators. 相似文献
72.
Kaisei Matsumoto Kazuki Ueno Prof. Dr. Jun Hirotani Prof. Dr. Yutaka Ohno Prof. Dr. Haruka Omachi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(28):6118-6121
Owing to their remarkable properties, single-walled carbon nanotube thin-film transistors (SWCNT-TFTs) are expected to be used in various flexible electronics applications. To fabricate SWCNT channel layers for TFTs, solution-based film formation on a self-assembled monolayer (SAM) covered with amino groups is commonly used. However, this method uses highly oxidized surfaces, which is not suitable for flexible polymeric substrates. In this work, a solution-based SWCNT film fabrication using methoxycarbonyl polyallylamine (Moc-PAA) is reported. The NH2-terminated surface of the cross-linked Moc-PAA layer enables the formation of highly dense and uniform SWCNT networks on both rigid and flexible substrates. TFTs that use the fabricated SWCNT thin film exhibited excellent performance with small variations. The presented simple method to access SWCNT thin film accelerates the realization of flexible nanoelectronics. 相似文献
73.
Emiko Igarashi Kenta Sakamoto Tomoyuki Yoshimura Jun-ichi Matsuo 《Tetrahedron letters》2019,60(1):13-15
Various 3-phenylcyclobutanones reacted with aliphatic and aromatic nitriles in the presence of Me3SiOTf to afford dihydropyridones by formal [4+2] cycloaddition. 相似文献
74.
75.
Effects of graded porous structure on local strain distribution under compression in silicone rubber
Keijiro Yoshimura Kazunori Nakano Takeshi Nishiwaki Yuki Iwama Masanobu Murata 《Journal of Polymer Science.Polymer Physics》2019,57(16):1033-1042
Silicone rubber samples with gradually changing pore sizes within the range of 70–610 μm are produced using an improved spacer method. The samples are scanned using an X‐ray computed tomography to evaluate their graded structure as compared to uniform rubber. A compressive test reveals that graded porous silicone rubber has characteristic stress–strain curves whose slope changes within a specific strain range depending on the porous structure. Analysis results of local strain based on a digital image correlation of the graded porous silicone rubber under compression demonstrate that the characteristic stress–strain properties are caused by shifts in the main deformation region in the graded structure. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2019 , 57, 1033–1042 相似文献
76.
Jin Tanaka Yu Shibata Anton Joseph Juntaro Nogami Jyunichi Terasawa Ryo Yoshimura Prof. Dr. Ken Tanaka 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(26):5774-5779
It has been established that a newly developed cyclopentadienyl rhodium(III) [CpARhIII] complex, bearing an acidic secondary amide moiety on the Cp ring, is able to catalyze the ortho-bromination of O-phenyl carbamates with N-bromosuccinimide (NBS) at room temperature. The presence of the acidic secondary amide moiety on the CpA ligand accelerates the bromination by the hydrogen bond between the acidic NH group of the CpA ligand and the carbonyl group of NBS. 相似文献
77.
78.
Dr. Yuki Ohishi Kentaro Masuda Kazuki Kudo Prof. Dr. Hajime Abe Prof. Dr. Masahiko Inouye 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(2):785-793
Generally, cage-shaped hosts for saccharides can bind strongly to guest molecules because of the three-dimensional preorganized hydrogen-bonding sites. However, the preparation of cage molecules is often difficult because of the low yield of the macrocyclization step. Here, we report a three-arm-shaped molecule possessing pyridine-acetylene-phenol units as a new kind of host having a preorganized three-dimensional hydrogen-bonding site. This three-arm-shaped host was readily prepared compared to a cage-shaped analogue. This host associated with lipophilic glycosides to form chiral complexes, and the association constants were sufficiently high as to be comparable to those of the cage-shaped analogue. Furthermore, this host extracted native monosaccharides into a lipophilic solvent. 相似文献
79.
Kentaro Okuma Kazuki Kojima Kosei Shioji 《Phosphorus, sulfur, and silicon and the related elements》2013,188(1):583-586
Reactions of selenobenzophenones with methyl propiolate afforded two types of cycloadducts regioselectively. The reaction with tetracyanoethylene gave selenophene derivatives. Mechanisms of these reactions were discussed. 相似文献
80.
Yoshiki Chujo Akio Naka Martina Krämer Kazuki Sada Takeo Saegusa 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(6):1213-1223
Abstract This paper describes the synthesis of various star-shaped polymers by means of complexation of bipyridyl-terminated polyoxyethylene with Ru(II) ion. Three kinds of bipyridyl-terminated polyoxyethylenes of different molecular weights were prepared from the corresponding polyoxyethylene monomethyl ethers with narrow molecular weight distributions. Bipyridyl was found to be introduced quantitatively at the end of the polymers based on the results of UV spectra. The formation of a star-shaped polymer was carried out by the reaction of RuCl3 with three equivalents of bipyridyl-terminated polyoxyethylene. The UV spectrum of the star-shaped polymer obtained supported the formation of a typical Ru(II) tris(bipyridyl) complex. From the results of GPC, the star-shaped polymer obtained had a higher molecular weight than the pre-polymer and showed a narrow molecular weight distribution. In the case of a Ni(II) or a Co(II) complex, however, the star-shaped polymer was found to be dissociated into three linear prepolymers under the conditions of GPC measurement. 相似文献