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131.
《Macromolecular bioscience》2017,17(9)
Carboxymethyl cellulose (CMC) is functionalized with norbornene groups to undergo thiol‐norbornene cross‐linking reactions. Hydrogels synthesized from a single norbornene‐modified carboxymethyl cellulose (NorCMC) via a light‐initiated thiol‐ene cross‐linking reaction with a variety of dithiol cross‐linkers yield hydrogels with a tunable compression modulus ranging from 1.7 to 103 kPa. Additionally, thermoresponsiveness is spatiotemporally imparted to NorCMC hydrogels by photopatterning a dithiol‐terminated poly(N‐isopropyl acrylamide) cross‐linker, enabling swelling and topological control of the hydrogels as a function of incubation temperature. NorCMC hydrogels are cytocompatible as the viability of encapsulated human mesenchymal stem cells (hMSCs) is greater than 85% after 21 d while using a variety of cross‐linkers. Moreover, hMSCs can remodel, adhere, and spread in the NorCMC matrix cross‐linked with a matrix metalloproteinase‐degradable peptide, further demonstrating the utility of these materials as a tunable biomaterial. 相似文献
132.
Chau N. Tang Hunaid B. Nulwala Krishnan Damodaran Palwinder Kaur David R. Luebke 《Journal of polymer science. Part A, Polymer chemistry》2011,49(9):2024-2032
CO2‐based, crosslinked poly(hydroxyl urethane)s (PHUs) are accessed via a set of efficient reactions based on the addition chemistry of thiol‐ene and amines‐cyclic carbonates. This strategy to utilize 5‐membered cyclic carbonates produced from CO2 is robust, facile, modular, and atomically efficient in nature. The thiol‐ene reaction was utilized to access bis(cyclic carbonate), tris(cyclic carbonate), and tetrakis(cyclic carbonate) in quantitative yield from 4‐vinyl‐1,3‐dioxolan‐2‐one and thiols. Multi‐functional cyclic carbonates were simply mixed with diethylenetriamine and/or 1,6‐diaminohexane to generate crosslinked PHUs from 25 to 80 °C. These materials are easy to scale‐up and are potential candidates in many applications such as coatings, binders, and resins. The resulting polymers have glass transition temperatures between ?1 and 16 °C and thermal decomposition temperatures from 190 to 230 °C. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
133.
134.
Christopher O. Bounds Ronald Goetter John A. Pojman Max Vandersall 《Journal of polymer science. Part A, Polymer chemistry》2012,50(3):409-422
We report a novel approach to prepare microparticles via a dispersion polymerization using the amine‐catalyzed addition of a trithiol to a triacrylate. Microparticles loaded with various core materials were produced and applied in various systems to improve the desired characteristics of the given system. We determined that this type of microparticle could be used as either a stimulated release or controlled release system for certain desired core materials. These microparticles were able to prevent the interaction between a Lewis acid initiator and fumed silica, improving the rheological properties of an epoxy system containing the initiator. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
135.
Firdaus Yhaya Arlingga Sutinah Andrew M. Gregory Mingtao Liang Martina H. Stenzel 《Journal of polymer science. Part A, Polymer chemistry》2012,50(19):4085-4093
The polymerization of vinyl methacrylate (VMA) allows the synthesis of polymers with pendant double bonds. When this polymerization was undertaken in the presence of 2‐cyanopropyl dithiobenzoate as reversible addition–fragmentation chain transfer agent, it led almost exclusively to vinylester functional sidegroups, which were available for further reactions. The vinylester functionality could not be functionalized using common thiol‐ene catalysts, but could be activated using Candida antarctica lipase B (CAL‐B) (Novozyme 435). The reaction between PVMA and various thiols in N, N‐dimethyl formamide in the presence of CAL‐B led exclusively to the formation of the anti‐Markovnikov product. The rate of reaction between PVMA and 1‐butanethiol was monitored using 1H NMR. The reaction was complete within 72 h. Similar results were obtained with other small‐sized thiols such as 2‐mercaptoethanol, 3‐mercaptopropionic acid, and 2‐(trimethylsilyl)ethanethiol, while more bulky thiols, such as secondary thiols, thiols with long alkyl chains, and sterically demanding thiols, such as mono(6‐deoxy‐6‐mercapto)‐β‐cyclodextrin, only led to lower conversions. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012 相似文献
136.
A highly efficient heterogeneous rhodium(I)‐catalyzed C–S coupling reaction of thiols with polychloroalkanes or alkyl halides under mild conditions
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Heterogeneous C–S coupling reaction of thiols with polychloroalkanes or alkyl halides was achieved at 30 or 80 °C in the presence of 5 mol% of an MCM‐41‐immobilized bidentate phosphine rhodium complex (MCM‐41‐2P‐RhCl(PPh3)) and triethylamine, yielding a variety of formaldehyde dithioacetals, ethylenedithioethers and unsymmetric thioethers in good to excellent yields. This heterogeneous rhodium catalyst can be easily recovered and recycled by simple filtration of the reaction solution and used for at least 10 consecutive trials without significant loss of activity. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
137.
Phuoc Dien Pham Vincent Lapinte Yann Raoul Jean‐Jacques Robin 《Journal of polymer science. Part A, Polymer chemistry》2014,52(11):1597-1606
Oleic acid and α,ω‐diacid were converted into propargylic esters followed by thiol‐ene/yne coupling (TEC/TYC) functionalization in presence of mercaptoethanol. The multiradical addition on fatty esters leads to the formation of lipidic polyols (OH1 and OH2), as judged by 1H NMR and mass spectroscopies as well as by size exclusion chromatography. The crosslinking reaction between TEC/TYC‐based polyols and 4,4′‐methylene bis(phenylisocyanate) isocyanate reactant was monitored by FTIR experiment and reaction parameters were optimized. By differential scanning calorimetry, relatively high glass transitions are measured corresponding to structure with little or without dangling chain. Moreover, the thermal stability of the resulting plant oil‐based polyurethane materials (PU1 and PU2) were found to be fully consistent with that of other lipidic PUs respecting a three‐step process. Thanks to TYC methodology, fatty α,ω‐diacid produces lipidic polyol without dangling chain and lipidic thermoset PU with relatively high Tg. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1597–1606 相似文献
138.
Ting Yang Hui Long Michael Malkoch E. Kristofer Gamstedt Lars Berglund Anders Hult 《Journal of polymer science. Part A, Polymer chemistry》2011,49(18):4044-4054
Considering the large number of applications for hydrogels, a better understanding of the relation between molecular structure and mechanical properties for well‐defined hydrogel is essential. A new library has been compiled of poly(ethylene glycol) polymers (PEG) of different length end functionalized with diallyl, dithiol, and dimethacrylate, and crosslinked with complementary trifunctional crosslinkers. In this study, the hydrogels were initially analyzed by FT‐Raman and NMR to study the conversion ratio of the functional groups. The effects of solvent type, solid content concentration, curing time and length of the PEG chains on the final leaching, swelling and tensile properties of the hydrogels were studied. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
139.
140.
Carl Fredrik Carlborg Alexander Vastesson Yitong Liu Wouter van der Wijngaart Mats Johansson Tommy Haraldsson 《Journal of polymer science. Part A, Polymer chemistry》2014,52(18):2604-2615
We present a facile two‐stage UV/UV activation method for the polymerization of off‐stoichiometry thiol‐ene‐epoxy, OSTE+, networks. We show that the handling and processing of these epoxy‐based resins is made easier by introducing a material with a controlled curing technique based on two steps, where the first step offers excellent processing capabilities, and the second step yields a polymer with suitable end‐properties. We investigate the sequential thiol‐ene and thiol‐epoxy reactions during these steps by studying the mechanical properties, functional group conversion, water absorption, hydrolytic stability, and thermal stability in several different thiol‐ene‐epoxy formulations. Finally, we conclude that the curing stages can be separated for up to 24 h, which is promising for the usefulness of this technique in industrial applications. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 2604‐2615 相似文献