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21.
22.
A semi-preparative high-performance liquid chromatography process was evaluated as a tool to quantitatively determine the
purity or percentage mass fraction content (% m/m) of organic compounds. The method is simple and does not require the identification and subsequent quantitation of organic-related
structure impurities. A protocol was developed and tested on four reference materials certified for purity from 95% m/m to 99.3% m/m. Comparing the purity results of each certified reference material using the new approach with their respective certified
values showed no significant analytical bias. Semi-preparative high-performance liquid chromatography has proved the potential
to be a primary method directly traceable to mass with an uncertainty statement written down also in terms of mass with expanding
uncertainty ranging from 0.8% to 1.3% m/m compared to 0.3 to 2.0% m/m for the certified purity values at the 95% confidence interval. 相似文献
23.
Djukic JP Iali W Pfeffer M Le Goff XF 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(19):6063-6078
Facial selectivity during the π-coordination of pseudo-tetrahedral iridacycles by neutral (Cr(CO)(3)), monocationic (Cp*Ru(+)), and biscationic (Cp*Ir(2+)) metal centers was directly influenced by the coulombic imbalance in the coordination sphere of the chelated Ir center. We also showed by using theoretical calculations that the feasibility of the related metallacycles that displayed metallocenic planar chirality was dependent to the presence of an electron-donating group, such as NMe(2), which contributed to the overall stability of the complexes. When the π-bonded moiety was the strongly electron-withdrawing Cp*Ir(2+) group, the electron donation from NMe(2) resulted in major conformational changes, with a barrier to rotation of about 17?kcal mol(-1) for this group that became spectroscopically diastereotopic (high-field (1)H?NMR spectroscopy). This peculiar property is proposed as a means to introduce a new type of constitutional chirality at the nitrogen center: planar chirality at tertiary aromatic amines. 相似文献
24.
SN Ding D Shan S Cosnier A Le Goff 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(37):11564-11568
Ru being served: A pyrene-Ru/SWCNT nanohybrid was formed through noncovalent π-π stacking interactions. After oxidative treatment, the pyrene-Ru/SWCNT-functionalized Pt electrode achieved a highly reversible redox process and exhibited excellent electrogenerated chemiluminescence behavior. 相似文献
25.
Fustier-Boutignon M Heuclin H Le Goff XF Mézailles N 《Chemical communications (Cambridge, England)》2012,48(27):3306-3308
Early transition metal nucleophilic carbene complexes have been used as stoichiometric carbene transfer agents in a transmetalation process. 相似文献
26.
Bernard Deschamps Xavier Le Goff Louis Ricard Pascal Le Floch 《Heteroatom Chemistry》2007,18(4):363-371
The 1‐methoxy‐2‐(supermesitylphosphanylidenemethyl)‐benzene ligand ( 1 ) was prepared by reacting the phospha‐Wittig reagent [Mes*PPMe3] with o‐methoxybenzaldehyde. Reaction of 1 with one equivalent of the [Pd(allyl)Cl]2 dimer in the presence of Ag(OTf) affords a neutral complex ( 4 ) in which the triflate ligand is coordinated to the palladium atom. DFT calculations show that the formation of complex 4 is favored by 22.4 kcal/mol with respect to that of a chelate species involving coordination of the ligand through the phosphorus atom of one lone pair at the oxygen of the pendant methoxy group. Reaction of two equivalents of ligand 1 with the [Pd(allyl)Cl]2 dimer affords complex 5 , in which the two ligands are coordinated through their phosphorus atom. The catalytic activity of complex 5 was compared to that of the 1,3‐bis[2‐(supermesityl)phosphanediylmethyl]benzene palladium chloride complex (6). Performances of the two catalysts were found to be similar in the Suzuki cross‐coupling reaction between phenylboronic acid and some arylbromides (TON between 55.105 and 99.105) as well as in the Sonogashira coupling between phenylacetylene and arylbromides (TON between 400 and 950). © 2007 Wiley Periodicals, Inc. Heteroatom Chem 18:363–371, 2007; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/hc.20307 相似文献
27.
Dr. Tarun Kumar Yan Yang Sirine Sghaier Dr. Yassir Zaid Dr. Xavier F. Le Goff Dr. Elodie Rousset Dr. Fabien Massicot Dr. Dominique Harakat Agathe Martinez Dr. Marc Taillefer Prof. Laurent Maron Prof. Jean-Bernard Behr Dr. Florian Jaroschik 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(12):4016-4021
The development of new fluorine-containing building blocks and their efficient synthetic access is currently a challenging research field. Herein, the highly regio- and stereoselective addition of a large range of aldehydes onto trifluoromethylated benzofulvenes was achieved using a simple La/I2/DIBAL-Cl system via a selective C−F bond activation process. This versatile methodology provided homodienyl alcohols bearing a terminal CF2-alkene with potential further applications, as shown by the dehydration to the first benzofulvenes carrying a difluorovinyl group. In addition, for certain electron-poor aldehydes, unprecedented ipso substitution of the CF3 group in a diene was observed, which, according to DFT studies, is related to the presence of the large, Lewis-acidic lanthanum metal. 相似文献
28.
A. Saifer M. Kornblum S. P. Worden I. B. Rushing I. P. Barnes A. P. Surer M. Farren Greta Hammarsten B. Melichar L. Vsetecka S. A. Poworinskaja Raimonde Duval J. M. Le Goff E. Justin-Mueller G. Haslewood E. King A. T. Cameron J. S. Guthrie F. D. White Th. Findley Regine Kapeller-Adler N. P. Meschkowa Rangier Lafrançaise P. A. Clifford H. J. Wichmann F. Timm E. Komm F. Kiermeier und A. Douglas-Sauermann 《Fresenius' Journal of Analytical Chemistry》1938,115(7-8):296-300
Ohne Zusammenfassung 相似文献
29.
Dr. Solène Gentil Dr. Pierre Rousselot-Pailley Ferran Sancho Dr. Viviane Robert Dr. Yasmina Mekmouche Prof. Victor Guallar Dr. Thierry Tron Dr. Alan Le Goff 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(21):4798-4804
A maximization of a direct electron transfer (DET) between redox enzymes and electrodes can be obtained through the oriented immobilization of enzymes onto an electroactive surface. Here, a strategy for obtaining carbon nanotube (CNTs) based electrodes covalently modified with perfectly control-oriented fungal laccases is presented. Modelizations of the laccase-CNT interaction and of electron conduction pathways serve as a guide in choosing grafting positions. Homogeneous populations of alkyne-modified laccases are obtained through the reductive amination of a unique surface-accessible lysine residue selectively engineered near either one or the other of the two copper centers in enzyme variants. Immobilization of the site-specific alkynated enzymes is achieved by copper-catalyzed click reaction on azido-modified CNTs. A highly efficient reduction of O2 at low overpotential and catalytic current densities over −3 mA cm−2 are obtained by minimizing the distance from the electrode surface to the trinuclear cluster. 相似文献
30.
Preparation of conjugated trienediamines from 1,9-bis-dialkylaminonona-2,7-diynes 1 is reactions of these compounds are reported, more particularly the addition of hydrogen mixture of diastereoisomeric bis-α-aminonitriles 12 which, in turn, can be used for synthetic 相似文献