全文获取类型
收费全文 | 779篇 |
免费 | 40篇 |
国内免费 | 1篇 |
专业分类
化学 | 721篇 |
晶体学 | 4篇 |
力学 | 3篇 |
数学 | 1篇 |
物理学 | 91篇 |
出版年
2023年 | 4篇 |
2022年 | 8篇 |
2021年 | 5篇 |
2020年 | 9篇 |
2019年 | 20篇 |
2018年 | 10篇 |
2017年 | 5篇 |
2016年 | 14篇 |
2015年 | 19篇 |
2014年 | 13篇 |
2013年 | 57篇 |
2012年 | 49篇 |
2011年 | 49篇 |
2010年 | 27篇 |
2009年 | 25篇 |
2008年 | 64篇 |
2007年 | 46篇 |
2006年 | 49篇 |
2005年 | 42篇 |
2004年 | 62篇 |
2003年 | 30篇 |
2002年 | 32篇 |
2001年 | 14篇 |
2000年 | 8篇 |
1999年 | 12篇 |
1998年 | 8篇 |
1997年 | 12篇 |
1996年 | 5篇 |
1995年 | 4篇 |
1994年 | 3篇 |
1993年 | 13篇 |
1992年 | 10篇 |
1991年 | 5篇 |
1990年 | 5篇 |
1986年 | 6篇 |
1985年 | 3篇 |
1984年 | 7篇 |
1983年 | 6篇 |
1982年 | 9篇 |
1981年 | 6篇 |
1980年 | 5篇 |
1979年 | 10篇 |
1978年 | 8篇 |
1977年 | 2篇 |
1976年 | 6篇 |
1974年 | 3篇 |
1972年 | 3篇 |
1970年 | 1篇 |
1967年 | 2篇 |
1964年 | 1篇 |
排序方式: 共有820条查询结果,搜索用时 15 毫秒
1.
Atsuhiro Fujimori Mikako Ishitsuka Hiroo Nakahara Eisuke Ito Masahiko Hara Kaname Kanai Hisao Ishii Yukio Ouchi Kazuhiko Seki 《Journal of Polymer Science.Polymer Physics》2004,42(12):2329-2336
Photopolymerization of cadmium 10,12-pentacosadiynoate (CdDA) in Langmuir–Blodgett (LB) films, with the molecular packing well arranged by moderate preannealing, was investigated with near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. Greenish films of polydiacetylene with an absorption wavelength of 705 nm were obtained through the photopolymerization of preannealed monomer LB films, and this resulted in an extended π-conjugate system based on the well-ordered monomer in a two-dimensional arrangement. The electronic structures of the polydiacetylenes were found to be correlated to the variation of the molecular arrangements in the films from the changes in the NEXAFS spectra through photopolymerization in the LB films. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 2329–2336, 2004 相似文献
2.
Yamashita Hiromi Ariyuki Masao Yoshizawa Katsuhiro Kida Keiko Ohshiro Satoshi Anpo Masakazu 《Research on Chemical Intermediates》2004,30(2):235-245
The photocatalytic reactivities of chromium-containing mesoporous silica molecular sieves (Cr-HMS) under visible light irradiation have been investigated. Cr-HMS involves tetrahedral chromium oxide (Cr-oxide) moieties which are highly dispersed and incorporated in the framework of molecular sieve with two terminal Cr=O groups. In the presence of propane with molecular oxygen, a partial oxidation proceeded under visible light irradiation to produce acetone and acrolein, with high selectivity, while a complete oxidation proceeded under UV light irradiation mainly to produce CO2. The charge-transfer excited state of the tetrahedral Cr-oxide moieties plays a significant role in the photocatalytic reactions. 相似文献
3.
Hirofumi Kuroda Emi Hanaki Hironori Izawa Michiko Kano Hiromi Itahashi 《Tetrahedron》2004,60(8):1913-1920
α-Vinylfurans were obtained by phosphine-initiated cyclization of various enynes bearing a carbonyl group at the ene end in the presence of various aldehydes, in moderate to high yields. The reaction may consist of 1,6-addition of phosphine to the enynes, ring closure, and Wittig reaction between the ylid resulting from cyclization and an aldehyde. Thus, various aldehydes were able to be used in the reaction. The reaction was influenced greatly by the substituents at the acetylene position (R1) and the α-position of the carbonyl group (R3). 相似文献
4.
Hiroshi Sakurai Fumitake Itoh Katsuyoshi Takano Hiromi Oike 《Journal of Physics and Chemistry of Solids》2004,65(12):2083-2088
A novel technique of measuring a magnetic Compton profile using the grazing angle geometry against a sample surface (Grazing Incidence Magnetic Compton Profile) has been successively developed. Measurements of a magnetic moment and a magnetic Compton profile are possible for a Fe 200 nm film on a thick glass substrate. The estimated thinnest limit for measurements is 100 nm for a Fe film. 相似文献
5.
Hiromi Matsuhashi Masakazu Oikawa Hiromi Shibata Michiko Tanaka 《Reaction Kinetics and Catalysis Letters》1998,65(2):253-258
Reversible formation of F+-centers was observed over platinum promoted sulfated zirconia in the presence and absence of hydrogen. The intensity of ESR
signal of F+-centers was increased by treatment in He stream and it was decreased rapidly by supply of hydrogen in gas phase. This behavior
seems to be related to proton spillover. 相似文献
6.
Yuko Ouchi Yasuhiro Morisaki Dr. Tomoki Ogoshi Dr. Yoshiki Chujo Prof. Dr. 《化学:亚洲杂志》2007,2(3):397-402
A reaction of the P‐chiral compound (S,S)‐1,2‐bis(boranato(tert‐butyl)methylphosphino)ethane with an azobenzene derivative gave stimuli‐responsive polymers with P‐chiral phosphines in the main chain. This is the first example of a stimuli‐responsive P‐chiral polymer. The polymer isomerized from the trans to the cis form upon UV irradiation and reverted to the trans form reversibly. The polymer was able to coordinate to platinum, and the resulting polymer complex exhibited the Cotton effect owing to the chirality of the phosphorus atoms. The structure of the P‐chiral polymer obtained could be changed reversibly by light and thermal stimuli, and the polymer chain was induced to rotate helically when complexed with transition metals through the chiral phosphorus atoms. 相似文献
7.
A poly(N-isopropylacrylamide) (PNIPAAm)-like biodegradable thermosensitive polydepsipeptide, poly[Glc-Asn(N-isopropyl)], was synthesized by introducing an isopropyl amide group into poly[Glc-Asn]. Poly[Glc-Asn(N-isopropyl)] was degraded in vitro by cleavage of the ester bonds in the main chain in water at room temperature. The non-toxic nature of the polymer and its degradation products, coupled with a cloud point at 29 degrees C in water, make this polymer attractive for biomedical implant applications. 相似文献
8.
Tatsuro Ouchi Hirotoshi Fujie Satoshi Jokei Yoshiomi Sakamoto Hidenori Chikashita Takeshi Inoi Otto Vogl 《Journal of polymer science. Part A, Polymer chemistry》1986,24(9):2059-2074
Acryloyl-type polymer fixing 1-β-carbonylethyl-5-fluorouracil residues through D -glucofuranoses via ester bonds was synthesized by means of polymerization of the corresponding monomer and polymer reaction. In order to provide the water-soluble objective polymer, the copolymerization of the acryloyl-type monomer with acrylamide was carried out. The extent of release of 5-FU residues from the copolymer was investigated in the enzyme or nonenzyme system in vitro. Furthermore, the antitumor activities of the water-insoluble homopolymer and water-soluble copolymer obtained were tested in vivo. 相似文献
9.
Tatsuro Ouchi Tamio Nishimura Minoru Imoto 《Journal of polymer science. Part A, Polymer chemistry》1976,14(11):2695-2702
It was found recently that the system of nylon 3, copper(II) ion, and water could initiate a radical polymerization of methyl methacrylate(MMA). In the present paper, the effect of average chain length of the molecules of nylon 3 on the rate of polymerization of MMA was studied. The rate increased with the chain length of nylon 3. This result was explained well by the fact that the shorter nylon 3 forms a complex with copper (II) ion more easily than longer nylon 3. It was assumed that the shorter nylon 3 fills three or four coordination sites of copper(II) ion and loses the ability to initiate the polymerization. The efficiency of grafting of MMA and the degree of polymerization of MMA homopolymer were independent of the chain length of nylon 3. 相似文献
10.
A hybrid approach combining energy density analysis with the interaction energy decomposition method
We propose a new analysis technique for characterizing molecular interactions that combines an energy decomposition scheme, such as the Kitaura-Morokuma decomposition method, with energy density analysis, which partitions the total energy of the system into atomic contributions. The combined scheme, termed Interaction-EDA, enables us to estimate the local contribution of interaction energy components, such as electrostatic, exchange, polarization, and charge transfer. The evaluation of the local interaction energy is rather important in large systems. For a numerical assessment, the Interaction-EDA method is applied to the process of CO adsorption on Si(100) - (2 x 1) surface. 相似文献