全文获取类型
收费全文 | 275篇 |
免费 | 9篇 |
专业分类
化学 | 220篇 |
晶体学 | 2篇 |
力学 | 5篇 |
数学 | 6篇 |
物理学 | 51篇 |
出版年
2023年 | 1篇 |
2021年 | 4篇 |
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 3篇 |
2016年 | 7篇 |
2015年 | 7篇 |
2014年 | 8篇 |
2013年 | 10篇 |
2012年 | 15篇 |
2011年 | 19篇 |
2010年 | 5篇 |
2009年 | 12篇 |
2008年 | 24篇 |
2007年 | 18篇 |
2006年 | 17篇 |
2005年 | 13篇 |
2004年 | 19篇 |
2003年 | 10篇 |
2002年 | 6篇 |
2001年 | 4篇 |
2000年 | 5篇 |
1999年 | 10篇 |
1998年 | 6篇 |
1997年 | 2篇 |
1996年 | 1篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 3篇 |
1990年 | 1篇 |
1989年 | 4篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 3篇 |
1985年 | 2篇 |
1984年 | 1篇 |
1982年 | 5篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1978年 | 2篇 |
1977年 | 3篇 |
1976年 | 4篇 |
1974年 | 3篇 |
1973年 | 2篇 |
排序方式: 共有284条查询结果,搜索用时 15 毫秒
221.
Kataoka T Tsukahara Y Hasegawa Y Wada Y 《Chemical communications (Cambridge, England)》2005,(48):6038-6040
Size-controlled EuS nanoparticles were synthesized by the reaction of europium metal with thiourea as a sulfur source in liq. NH3, whose surface was confirmed to be modified with thiourea by FT-IR measurement, and the opto-magnetic properties (Faraday effect) of the EuS nanoparticles were investigated by using PMMA films containing the nanoparticles, showing that their Faraday rotation peaks were adjustable by control of their particle size. 相似文献
222.
Yasuhisa Tsukahara Katsuji Ito Hsi-Chuan Tsai Yuya Yamashita 《Journal of polymer science. Part A, Polymer chemistry》1989,27(4):1099-1114
Water-soluble graft copolymers of well-defined structure having hydrophobic polymethacrylate branches with different ester groups were prepared by the macromonomer method. Methacrylate macromonomers of controlled molecular weights having a methacryloyloxyl end group were synthesized by radical polymerization of the corresponding monomer in the presence of thioglycolic acid followed by the reaction of glycidyl methacrylate with the terminal carboxyl group. These macromonomers were copolymerized with methacrylic acid and methyl methacrylate to prepare tailor-made graft copolymers composed of a hydrophlic backbone and different kinds of hydrophobic branches, which were characterized by elemental analysis, NMR, and GPC. The viscosities of the aqueous solutions of the sodium salts of these graft copolymers were measured. It was found that the viscosity of the dilute solution of the graft copolymer was remarkably high compared with the corresponding random copolymer irrespective of the ester group in branch segments. Solubilizing behavior of Orange-OT in aqueous solutions of the graft copolymers and the random copolymer were also investigated to study the nature of the hydrophobic domain of the graft copolymers. 相似文献
223.
Masayori Hagimori Kenichirou Yokota Ai Fukuda Yasuhisa Nishimura Ryousuke Satodani Bo‐Cheng Wang Ho‐Hsiang Wei San‐Lang Wang Yasuhiro Shigemitsu Yoshinori Tominaga 《Journal of heterocyclic chemistry》2016,53(2):414-420
New fluorescent compounds, 2‐substituted indeno[1,2‐d]pyrimidin‐5‐ones ( 3a , 3b , 3c , 3d ) were synthesized in good yield by the reaction of 2‐[bis(methylsulfanyl)methylene]indan‐1,3‐dione ( 1 ) with the respective amidine derivatives [guanidine carbonate ( 2a ), acetamidine hydrochloride ( 2b ), S‐methylisothiourea sulfate ( 2c ), and S‐benzylisothiourea sulfate ( 2d )]. 4‐Substituted amino‐2‐aminoindeno[1,2‐d]pyrimidin‐5‐ones ( 7b , 7c , 7d ) were synthesized by a one‐pot reaction of 1 , 2a and the respective amine compounds ( 4b , 4c , 4d ) in pyridine. These fused pyrimidine derivatives showed fluorescence in the solid state. 相似文献
224.
An efficient enantioselective synthesis of sn-2-aminooxy (AO) analogues of lysophosphatidic acid (LPA) that possess palmitoyl and oleoyl acyl chains is presented. Both sn-2-AO LPA analogues are agonists for the LPA1, LPA2, and LPA4 G-protein-coupled receptors, but antagonists for the LPA3 receptor and inhibitors of autotaxin (ATX). Moreover, both analogues stimulate migration of intestinal epithelial cells in a scratch wound assay. 相似文献
225.
Yamamura Y Shimoi H Sumita M Yasuzuka S Adachi K Fuyuhiro A Kawata S Saito K 《The journal of physical chemistry. A》2008,112(19):4465-4469
The heat capacity of [Hdamel]2[Cu(II)(tdpd)2] x 2 THF was measured from 6 to 250 K by adiabatic calorimetry. There are four heat anomalies around 150 K associated with disordering in the orientation of the uncoordinated THF molecules and in the conformation of the out-of-plane allyl groups of [Hdamel](+) units. The total entropy of transition was determined to be 19.8 J K(-1) mol(-1), less than the 4R ln 2 (R = gas constant) expected from the crystal structure at room temperature. The smallness of the total entropy change on phase transitions proves the presence of the strong motional correlation between the adjacent allyl groups. The calorimetric conclusion agreed with the crystal structure at 200 K re-examined in this study. 相似文献
226.
227.
The microscopic diffusion processes of NO molecules on Pt(997) at low coverage were investigated using time-resolved infrared reflection absorption spectroscopy (TR-IRAS). When NO molecules adsorb on Pt(997) at low temperature, each molecule transiently migrates on the surface from the first impact point to a possible adsorption site. At 11 K, the molecules are trapped at four adsorption sites on Pt(997): the on-top sites on the (111) terrace (OT), the hollow sites on the (111) terrace (HT), the bridge sites at the step (BS) and the hollow sites at the step downstream (HS). Based on the initial population ratio for these sites, the mean lateral displacement by transient migration is estimated to be 4.1 A. By heating the surface to 45 K, the HS species migrate up to the BS sites; the migration barrier is roughly estimated to be 120 meV. In the temperature range from 70 to 77 K, TR-IRAS measurements were carried out to observe the site change of OT species to the adjacent HT sites at isothermal conditions; the activation barrier and the preexponential factor are estimated to be 200 meV and 2.0 x 10(11) s(-1), respectively. In the temperature range from 100 to 110 K, the HT species migrate across the terrace and finally reach the BS sites. The activation barrier between the HT sites and the preexponential factor are estimated to be 290 meV and 6.5 x 10(11) s(-1), respectively, from the TR-IRAS data together with kinetic Monte Carlo simulations. On the whole, the quantitative microscopic picture of NO migration on Pt(997) has been established. 相似文献
228.
C.‐S. Deng H. E. Assender F. Dinelli O. V. Kolosov G. A. D. Briggs T. Miyamoto Y. Tsukahara 《Journal of Polymer Science.Polymer Physics》2000,38(23):3151-3162
The nucleation and initial stages of growth of aluminium oxide deposited on two different polymer surfaces [poly(ethylene terephthalate), (PET) and amorphous polypropylene, (PP)] have been studied by atomic force microscopy (AFM). The permeation of water vapor and oxygen through the films has been measured. The initial stages of the growth of the oxide consisted of separated islands on the polymer surface. Further growth of oxide depends strongly on the surface morphology and chemical nature of the polymer surface. Growth on PET follows a layer‐by‐layer mechanism that maintains the native surface roughness of the polymer substrate. Growth on PP, however, follows an island mode, which leads to an increase in surface roughness. This may be due to a lack of chemical bonding between the polymer and the arriving metal–oxygen particles. The oxide layer on PET grows more densely than on PP, providing superior barrier to gas permeation. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 3151–3162, 2000 相似文献
229.
230.