全文获取类型
收费全文 | 1617篇 |
免费 | 162篇 |
国内免费 | 5篇 |
专业分类
化学 | 1416篇 |
晶体学 | 21篇 |
力学 | 13篇 |
数学 | 68篇 |
物理学 | 266篇 |
出版年
2023年 | 22篇 |
2022年 | 14篇 |
2021年 | 38篇 |
2020年 | 62篇 |
2019年 | 70篇 |
2018年 | 41篇 |
2017年 | 26篇 |
2016年 | 96篇 |
2015年 | 86篇 |
2014年 | 85篇 |
2013年 | 99篇 |
2012年 | 176篇 |
2011年 | 202篇 |
2010年 | 75篇 |
2009年 | 59篇 |
2008年 | 123篇 |
2007年 | 96篇 |
2006年 | 87篇 |
2005年 | 79篇 |
2004年 | 67篇 |
2003年 | 36篇 |
2002年 | 31篇 |
2001年 | 14篇 |
2000年 | 7篇 |
1999年 | 7篇 |
1998年 | 7篇 |
1997年 | 9篇 |
1996年 | 2篇 |
1995年 | 5篇 |
1994年 | 6篇 |
1993年 | 3篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1990年 | 4篇 |
1988年 | 2篇 |
1986年 | 6篇 |
1985年 | 4篇 |
1984年 | 6篇 |
1983年 | 4篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 2篇 |
1979年 | 1篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 2篇 |
1975年 | 2篇 |
1973年 | 1篇 |
1968年 | 2篇 |
1937年 | 1篇 |
排序方式: 共有1784条查询结果,搜索用时 328 毫秒
71.
Yusuke Shiraki Kazuhiro Tsuruta Junpei Morimoto Chihiro Ohba Akifumi Kawamura Ryo Yoshida Ryuji Kawano Tadashi Uragami Takashi Miyata 《Macromolecular rapid communications》2015,36(6):515-519
Microdevices designed for practical environmental pollution monitoring need to detect specific pollutants such as dioxins. Bisphenol A (BPA) has been widely used as a monomer for the synthesis of polycarbonate and epoxy resins. However, the recent discovery of its high potential ability to disrupt human endocrine systems has made the development of smart systems and microdevices for its detection and removal necessary. Molecule‐responsive microsized hydrogels with β‐cycrodextrin (β‐CD) as ligands are prepared by photopolymerization using a fluorescence microscope. The molecule‐responsive micro‐hydrogels show ultra‐quick shrinkage in response to target BPA. Furthermore, the flow rate of a microchannel is autonomously regulated by the molecule‐responsive shrinking of their hydrogels as smart microvalves.
72.
Rate constant measurements for initial addition reactions of radicals at the propagation step of photo‐polymerization as studied by pulsed EPR spectroscopy 下载免费PDF全文
Yusuke Miyake Yutaka Marushima Hirona Takahashi Nobuyuki Akai Kazuhiko Shibuya Akio Kawai 《Journal of Physical Organic Chemistry》2016,29(9):468-475
Pulsed EPR spectroscopy was employed to determine reaction rate constants at an early stage of addition reactions in radical polymerizations triggered by four initiator radicals, which were generated by photodissociation of four parent molecules. Two monomers (tert‐butylacrylate and tert‐butylmethacrylate) were examined as reactant. Stern–Volmer analysis on the measured decay time of electron spin echo intensity of reacting radicals provides rate constants for addition reactions. We focused on rate constants for the second step reaction between monomer and adduct radical that is produced by the first step addition reaction between initiator radical and monomer. The rate constant measured by pulsed EPR was evaluated by theoretical calculations in the light of (1) enthalpy difference between product radical and reactants and (2) charge transfer interaction between reacting radical and monomer. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
73.
Herein reported is a photo-induced production of vicinal diols from alkenes under mild reaction conditions. The present dihydroxylation method using diacetyl (= butane-2,3-dione), oxygen, and water dispenses with toxic reagents and intractable waste generation. 相似文献
74.
Yusuke Sasano Shota Nagasawa Mai Yamazaki Dr. Masatoshi Shibuya Prof. Dr. Jaiwook Park Prof. Dr. Yoshiharu Iwabuchi 《Angewandte Chemie (International ed. in English)》2014,53(12):3236-3240
The direct oxidation of unprotected amino alcohols to their corresponding amino carbonyl compounds has often posed serious challenges in organic synthesis and has constrained chemists to adopting an indirect route, such as a protection/deprotection strategy, to attain their goal. Described herein is a highly chemoselective aerobic oxidation of unprotected amino alcohols to their amino carbonyl compounds in which 2‐azaadamantane N‐oxyl (AZADO)/copper catalysis is used. The catalytic system developed leads to the alcohol‐selective oxidation of various unprotected amino alcohols, carrying a primary, secondary, or tertiary amino group, in good to high yield at ambient temperature with exposure to air, thus offering flexibility in the synthesis of nitrogen‐containing compounds. 相似文献
75.
Back Cover: Chemical Preparation of Ferroelectric Mesoporous Barium Titanate Thin Films: Drastic Enhancement of Curie Temperature Induced by Mesopore‐Derived Strain (Chem. Eur. J. 36/2014) 下载免费PDF全文
76.
Back Cover: Amphiphilic Inclusion Spaces for Various Guests and Regulation of Fluorescence Intensity of 1,8‐Bis(4‐aminophenyl)anthracene Crystals (Chem. Eur. J. 11/2014) 下载免费PDF全文
77.
Dr. Victor Malgras Dr. Priyanka Jood Dr. Ziqi Sun Prof. Shi Xue Dou Prof. Yusuke Yamauchi Prof. Jung Ho Kim 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(33):10451-10455
Porous titanium dioxide synthesized with a bicontinuous surfactant template is a promising method that leads to a high active surface area electrode. The template used is based on a water/isooctane/dioctyl sodium sulfosuccinate salt together with lecithin. Several parameters were varied during the synthesis to understand and optimize channel formation mechanisms. The material is patterned in stacked conical channels, widening towards the centre of the grains. The active surface area increased by 116 % when the concentration of alkoxide precursors was decreased and increased by 241 % when the template formation temperature was decreased to 10 °C. Increasing the oil phase viscosity tends to widen the pore aperture, thus decreasing the overall active surface area. Changing the phase proportions alters the microemulsion integrity and disrupts channel formation. 相似文献
78.
Single‐Crystal‐like Nanoporous Spinel Oxides: A Strategy for Synthesis of Nanoporous Metal Oxides Utilizing Metal‐Cyanide Hybrid Coordination Polymers 下载免费PDF全文
Masataka Imura Rahul R. Salunkhe Naoto Umezawa Hicham Hamoudi Alexei A. Belik Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(52):17375-17384
Development of a new method to synthesize nanoporous metal oxides with highly crystallized frameworks is of great interest because of their wide use in practical applications. Here we demonstrate a thermal decomposition of metal‐cyanide hybrid coordination polymers (CPs) to prepare nanoporous metal oxides. During the thermal treatment, the organic units (carbon and nitrogen) are completely removed, and only metal contents are retained to prepare nanoporous metal oxides. The original nanocube shapes are well‐retained even after the thermal treatment. When both Fe and Co atoms are contained in the precursors, nanoporous Fe?Co oxide with a highly oriented crystalline framework is obtained. On the other hand, when nanoporous Co oxide and Fe oxide are obtained from Co‐ and Fe‐contacting precursors, their frameworks are amorphous and/or poorly crystallized. Single‐crystal‐like nanoporous Fe?Co oxide shows a stable magnetic property at room temperature compared to poly‐crystalline metal oxides. We further extend this concept to prepare nanoporous metal oxides with hollow interiors. Core‐shell heterostructures consisting of different metal‐cyanide hybrid CPs are prepared first. Then the cores are dissolved by chemical etching using a hydrochloric acid solution (i.e., the cores are used as sacrificial templates), leading to the formation of hollow interiors in the nanocubes. These hollow nanocubes are also successfully converted to nanoporous metal oxides with hollow interiors by thermal treatment. The present approach is entirely different from the surfactant‐templating approaches that traditionally have been utilized for the preparation of mesoporous metal oxides. We believe the present work proves a new way to synthesize nanoporous metal oxides with controlled crystalline frameworks and architectures. 相似文献
79.
Mesoporous Silica Particles as Topologically Crosslinking Fillers for Poly(N‐isopropylacrylamide) Hydrogels 下载免费PDF全文
Prof. Nobuyoshi Miyamoto Kotaro Shimasaki Kosuke Yamamoto Morio Shintate Yuichiro Kamachi Dr. Bishnu Prasad Bastakoti Dr. Norihiro Suzuki Dr. Ryuhei Motokawa Prof. Yusuke Yamauchi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(46):14955-14958
Here it is demonstrated that mesoporous silicas (MPSs) can be used as effective “topological crosslinkers” for poly(N‐isopropylacrylamide) (PNIPA) hydrogels to improve the mechanical property. Three‐dimensional bicontinuous mesporous silica is found to effectively reinforce the PNIPA hydrogels, as compared to nonporous silica and two‐dimensional hexagonally ordered mesoporous silica. 相似文献
80.
Well‐Defined Iron Complexes as Efficient Catalysts for “Green” Atom‐Transfer Radical Polymerization of Styrene,Methyl Methacrylate,and Butyl Acrylate with Low Catalyst Loadings and Catalyst Recycling 下载免费PDF全文
So‐ichiro Nakanishi Dr. Mitsunobu Kawamura Hidetomo Kai Prof. Dr. Ren‐Hua Jin Dr. Yusuke Sunada Prof. Dr. Hideo Nagashima 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(19):5802-5814
Environmentally friendly iron(II) catalysts for atom‐transfer radical polymerization (ATRP) were synthesized by careful selection of the nitrogen substituents of N,N,N‐trialkylated‐1,4,9‐triazacyclononane (R3TACN) ligands. Two types of structures were confirmed by crystallography: “[(R3TACN)FeX2]” complexes with relatively small R groups have ionic and dinuclear structures including a [(R3TACN)Fe(μ‐X)3Fe(R3TACN)]+ moiety, whereas those with more bulky R groups are neutral and mononuclear. The twelve [(R3TACN)FeX2]n complexes that were synthesized were subjected to bulk ATRP of styrene, methyl methacrylate (MMA), and butyl acrylate (BA). Among the iron complexes examined, [{(cyclopentyl)3TACN}FeBr2] ( 4 b ) was the best catalyst for the well‐controlled ATRP of all three monomers. This species allowed easy catalyst separation and recycling, a lowering of the catalyst concentration needed for the reaction, and the absence of additional reducing reagents. The lowest catalyst loading was accomplished in the ATRP of MMA with 4 b (59 ppm of Fe based on the charged monomer). Catalyst recycling in ATRP with low catalyst loadings was also successful. The ATRP of styrene with 4 b (117 ppm Fe atom) was followed by precipitation from methanol to give polystyrene that contained residual iron below the calculated detection limit (0.28 ppm). Mechanisms that involve equilibria between the multinuclear and mononuclear species were also examined. 相似文献