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91.
One‐Pot Synthesis of Highly Substituted Polyheteroaromatic Compounds by Rhodium(III)‐Catalyzed Multiple CH Activation and Annulation 下载免费PDF全文
Jayachandran Jayakumar Dr. Kanniyappan Parthasarathy Yi‐Hsiang Chen Tai‐Hua Lee Prof. Dr. Shih‐Ching Chuang Prof. Dr. Chien‐Hong Cheng 《Angewandte Chemie (International ed. in English)》2014,53(37):9889-9892
A new method for the synthesis of highly substituted naphthyridine‐based polyheteroaromatic compounds in high yields proceeds through rhodium(III)‐catalyzed multiple C? H bond cleavage and C? C and C? N bond formation in a one‐pot process. Such highly substituted polyheteroaromatic compounds have attracted much attention because of their unique π‐conjugation, which make them suitable materials for organic semiconductors and luminescent materials. Furthermore, a possible mechanism, which involves multiple chelation‐assisted ortho C? H activation, alkyne insertion, and reductive elimination, is proposed for this transformation. 相似文献
92.
Regiospecific Coordination of Re3 Clusters with the Sumanene‐Type Hexagons on Endohedral Metallofullerenes and Higher Fullerenes That Provides an Efficient Separation Method 下载免费PDF全文
Dr. Chia‐Hsiang Chen Dong‐Yui Lin Dr. Wen‐Yann Yeh 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(19):5768-5775
The reactions of [(μ‐H)3Re3(CO)11(NCMe)] with Sc2@C82‐C3v(8), Sc2C2@C80‐C2v(5), Sc2O@C82‐Cs(6), C86‐C2(17), and C86‐Cs(16) have been carried out to produce face‐capping cluster complexes. The Re3 triangles are found to bind to the sumanene‐type hexagons on the fullerene surface regiospecifically. In contrast, Sc3N@C78‐D3h(5) and Sc3N@C80‐Ih show no reactivity toward [(μ‐H)3Re3(CO)11(NCMe)], probably due to electronic and steric factors. These complexes can be easily purified by using HPLC. Carbonylation of each complex releases the corresponding higher fullerene or endohedral metallofullerene in pure form. Remarkably, the C86‐C2(17) and C86‐Cs(16) isomers were successively separated through Re3 cluster complexation/decomplexation. This unique bonding feature may provide an attractive general strategy to purify as yet unresolved fullerene mixtures. 相似文献
93.
Hsiang‐Chun Chang Jia‐Qi Li Ching‐Kai Lin Yu‐Jung Hsu Tsung‐Han Tu Yi‐Liang Hsieh Hsiu‐Hao Hsu Gene‐Hsiang Lee Yi‐Hung Liu Chi‐How Peng 《中国化学会会志》2019,66(9):1119-1133
Poly(di(pyridin‐2‐yl)methyl acrylate) (PDPyMA), which was obtained by the free radical polymerization of designed coordinative monomer of di(pyridin‐2‐yl)methyl acrylate, is able to coordinate with various metal ions to form heterogeneous catalysts for diverse catalytic reactions. The Pd and Cu complexes supported by PDPyMA were developed for the heterogeneous Suzuki‐Miyaura reaction and Friedel‐Crafts alkylation, respectively. The PDPyMA‐based catalysts showed no significant decline of reactivity after five times recycling. However, the hydrolysis of the PDPyMA backbone under alkaline conditions limited the catalytic efficiency of this heterogeneous catalyst so that the coordinative monomer was redesigned as 1,1‐di(pyridine‐2‐yl)‐2‐(4‐vinylphenyl)ethan‐1‐ol and then 2,2′‐(1‐methoxy‐2‐(4‐vinylphenyl)ethane‐1,1‐diyl)dipyridine (MVPhDPy). With copolymerization of N‐isopropyl acrylamide (NIPAM), the efficiency of polymer‐based heterogeneous catalysts could be further raised, demonstrated by the increased turn over number in the Suzuki‐Miyaura reaction, which approached 5,260 by using the catalyst formed from poly(MVPhDPy‐co‐NIPAM) and Pd(OAc)2. poly(MVPhDPy‐co‐NIPAM) copolymer, therefore, could be a versatile platform to support different metal ions for various heterogeneous catalytic reactions. 相似文献
94.
I‐Ling Lin I‐Hsiang Chen Chi‐Fong Lin Yu‐Hsiang Lo Sheng‐Huei Yang Shinne‐Ren Lin Ming‐Jung Wu 《中国化学会会志》2008,55(3):668-674
A series of 1‐(6‐(2‐(2‐arylethynyl)phenyl)hexyn‐5‐yl)piperidin‐2‐ones 2a‐j were synthesized and their antitumor activities were evaluated. Of these compounds, 1‐(6‐(2‐(2‐(4‐nitrophenyl)ethynyl)phenyl)hexyn‐5‐yl)piperidin‐2‐one ( 2j ) showed the highest potency of growth inhibition activity, especially against the RPMI‐8226 (0.4 μM) and SR (0.02 μM) cell lines of human leukemia. Compound 2j also induced significant apoptotic progress in the cell cycle assay with the K‐562 cell line. 相似文献
95.
We report what is, to our knowledge, the first experimental observation of stable new bound soliton pairs at the 10 GHz repetition rate in a hybrid FM harmonic mode-locked Er-fiber laser (1177 soliton pairs simultaneously in the laser cavity). The two solitons in the soliton pair have the identical pulse shape and are with the antiphase (pi phase difference). Their time separation is about three times the FWHM soliton width and varies with the phase modulation strength. The corresponding mechanism for explaining the formation as well as the superior stability of these closely bound soliton pairs is also given. 相似文献
96.
97.
Sheng‐Huei Hsiao Ming‐Hsiang He 《Journal of polymer science. Part A, Polymer chemistry》2001,39(22):4014-4021
Three new bis(ether‐acyl chloride) monomers, 1,1‐bis[4‐(4‐chloroformylphenoxy)phenyl]cyclohexane ( 1a ), 5,5‐bis[4‐(4‐chloroformylphenoxy)phenyl]‐4,7‐methanohexahydroindan ( 1b ), and 9,9‐bis[4‐(4‐chloroformylphenoxy)phenyl]fluorene ( 1c ), were synthesized from readily available compounds. Aromatic polybenzoxazoles bearing ether and cardo groups were obtained by the low‐temperature solution polycondensation of the bis(ether‐acyl chloride)s with three bis(aminophenol)s and the subsequent thermal cyclodehydration of the resultant poly(o‐hydroxy amide)s. The intermediate poly(o‐hydroxy amide)s exhibited inherent viscosities in the range of 0.35–0.71 dL/g. All of the poly(o‐hydroxy amide)s were amorphous and soluble in many organic polar solvents, and most of them could afford flexible and tough films by solvent casting. The poly(o‐hydroxy amide)s exhibited glass‐transition temperatures (Tg's) in the range of 141–169 °C and could be thermally converted into the corresponding polybenzoxazoles approximately in the region of 240–350 °C, as indicated by the DSC thermograms. Flexible and tough films of polybenzoxazoles could be obtained by thermal cyclodehydration of the poly(o‐hydroxy amide) films. All the polybenzoxazoles were amorphous and showed an enhanced Tg but a dramatically decreased solubility as compared with their poly(o‐hydroxy amide) precursors. They exhibited Tg's of 215–272 °C by DSC and showed insignificant weight loss before 500 °C in nitrogen or air. © 2001 John Wiley & Sons, Inc. J Polym Sci Part A: Polym Chem 39: 4014–4021, 2001 相似文献
98.
The first metal‐carbon bond β‐form paddlewheel complexes containing a Pd24+ core, [Pd(η2‐dithio)]2(μ‐dppa)( μ‐SCNMe2) (dithio = S2P(OEt)2, 2 ; S2COEt, 3 ; S2CNC4H8, 4 ), were prepared by the reactions of the α‐form paddlewheel‐type Pd2+4 dipalladium complex [Pd2 (μ‐Hdppa)2(μ‐SCNMe2)2][Cl]2, 1 with various dithio‐ligands, [NH4][S2P(OEt)2], [K][S2COEt] and [NH4][S2CNC4H8], in methanol at ambient temperature (Hdppa = bis(diphenylphosphino)amine). Electronic spectra and two X‐ray structures of the Pd2+4 species have been determined. 相似文献
99.
So‐Hsiang Chou Songnian He Wen‐Wei Lin 《Numerical Methods for Partial Differential Equations》2004,20(1):104-127
Compared with standard Galerkin finite element methods, mixed methods for second‐order elliptic problems give readily available flux approximation, but in general at the expense of having to deal with a more complicated discrete system. This is especially true when conforming elements are involved. Hence it is advantageous to consider a direct method when finding fluxes is just a small part of the overall modeling processes. The purpose of this article is to introduce a direct method combining the standard Galerkin Q1 conforming method with a cheap local flux recovery formula. The approximate flux resides in the lowest order Raviart‐Thomas space and retains local conservation property at the cluster level. A cluster is made up of at most four quadrilaterals. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq 20: 104–127, 2004 相似文献
100.