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21.
M. A. Haimova M. D. Palamareva C. I. Novkova B. J. Kurtev C. A. Petrova T. I. Arnaudov 《Monatshefte für Chemie / Chemical Monthly》1970,101(3):855-865
Zusammenfassung Durch Umsetzung von Hydramiden mit am aromatischen Ring m,p-dialkoxysubstituierten Arylessigsäureestern in Gegenwart von wasserfr. AlCl3 entstehen Gemische aus Estern der (±)-erythro- und (±)-threo-3-Amino-2,3-diarylpropansäuren. Bei der Umsetzung von Piperonalhydramid mit dem Methylester der Homoveratrumsäure konnte lediglich daserythro-Diastereomere isoliert werden.Die diastereomeren Ester wurden zu den jeweiligen (±)-erythro- und (±)-threo-3-Amino-2,3-diaryl-1-propanolen reduziert, die als N,O-Dibenzoylderivate charakterisiert wurden. Ihre relativen Konfigurationen und die der zugehörigen Ester wurden auf Grund der IR-Spektren der diastereomeren Aminopropanole bestimmt. Die NMR-Spektren eines Diastereomerenpaares von Aminopropanolen bestätigen die ihnen chemisch zugeordneten Konfigurationen und ermöglichen den Nachweis auch ihrer bevorzugten Konformationen.
Synthesis and configuration of methyl esters of the diastereomeric (±)-3-amino-2,3-diarylpropanoic acids, the (±)-3-amino-2,3-diaryl-1-propanols and their derivatives
Reaction of hydramides with m,p-dialkoxysubstituted arylacetates in the presence of anhydrous AlCl3 generally leads to mixtures of the esters of the (±)-erythro- and (±)-threo-3-amino-2,3-diarylpropanoic acids. However, in the reaction of piperonal hydramide with methyl homoveratrate, only the correspondingerythro-diastereomer was obtained.Reduction of the diastereomeric esters gives the corresponding (±)-erythro- and (±)-threo-3-amino-2,3-diaryl-1-propanols, which can be characterized as N,O-dibenzoyl derivatives. Relative configurations of both alcohols and esters were determined by means of their IR spectra. Configurations were confirmed for one pair of diastereomeric amino alcohols by means of NMR spectra and preferred conformations deduced.相似文献
22.
A. P. Borisov L. A. Petrova T. P. Karpova V. D. Makhaev 《Russian Chemical Bulletin》1994,43(12):2107-2109
Tris(4-imino-2-pentanonato)chromium was prepared by solid-state synthesis under conditions of mechanical activation of a mixture of chromium(III) chloride and sodium 4-imino-2-pentanonate and characterized by IR spectroscopy, X-ray diffraction, and electronic absorption spectroscopy.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 12, pp. 2227–2229, December, 1994.The present work was carried out as a part of Project No. 1.164 Mechanochemical Synthesis of Complex Compounds of The State Scientific and Technical Program Ecologically Safe Processes in Chemistry and Chemical Technology with the financial support of the Ministry of Science of the RF. 相似文献
23.
Khoroshko LO Takhistov VV Petrova VN Viktorovskii IV Lahtiperä M Paasivirta J 《European journal of mass spectrometry (Chichester, England)》2004,10(5):731-736
Structures of six cyclic polysulfides, previously unknown as organic environmental pollutants, were analyzed from a sediment sample from the Eastern Gulf of Finland. The determinations were done by gas chromatography connected to mass spectrometry. High resolution (HRMS) measurements of the isotopic composition of four compounds could be done to confirm their molecular formulae. Total low resolution (LRMS) spectra were used to elucidate structures of all six compounds by thermochemical approach, application of fragmentation rules and by ICLU simulation of the spectra. The compounds were deduced to be (in the order of GC- retention) 1,2,4-trithiacycloheptane, tetrathiacyclopentane, 1,2,4,5-tetrathia-cyclohexane, 1,2,3,4- tetrathiacycloheptane, 1,2,3,4-tetrathiacyclohexane and 1,2,4,6-tetrathiacyclooctane. 相似文献
24.
Anionic polymerization of methyl methacrylate in THF and toluene at ?70° was studied by means of i.r. spectroscopy. The reaction mixtures show characteristic absorption at 1600–1750 cm?1 caused by the stretching vibrations of the propagating centre as well as by the groups obtained in side reactions (metal splitting, addition to a carbonyl group, cyclization). Sec-butyllithium is more effective in THF than n-butyllithium, ethyllithium and fluorenyllithium. When polymerizing in toluene, small amounts of a donor (THF or HMPT) cause formation of active centres similar to those in pure THF. The “living” ends of oligo-MMA form 1:1 complexes with electron acceptors such as trialkylaluminium and triethylboron. 相似文献
25.
V. N. Charushin M. G. Ponizovskii O. N. Chupakhin A. I. Rezvukhin G. M. Petrova Yu. A. Efremov 《Chemistry of Heterocyclic Compounds》1981,17(11):1129-1134
The reactions of substituted quinoxalinium, benzo[g]- and benzo[f]quinoxalinium, and pyrido[2,3-b]pyrazinium salts with anions of -dicarbonyl compounds give furo[2,3-b]-annelated systems with strictly determined regio- and stereoorientations.See [1] for Communication 3.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1543–1548, November, 1981. 相似文献
26.
Single crystals of NaKZnP2O7 were grown, and their crystal structure was determined by X-ray diffraction (space group P21/n, a = 12.585(5) Å, b = 7.277(5) Å, c = 7.428(5) Å, β = 90.00(5)°, Z = 4, 1916 F(hkl), R 1 = 0.0461). The structure contains a 3D tetrahedral zinc phosphate framework with a system of intersecting channels running along the b and c axes. The sodium and potassium atoms are coordinated to six and seven oxygen atoms, respectively, and reside inside these channels; the potassium cations, which are larger than the sodium cations, are located at channel intersections. 相似文献
27.
Boris Shivachev Rosica Petrova Petja Marinova Neyko Stoyanov Anife Ahmedova Mariana Mitewa 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(4):o211-o215
The crystal structures of four cycloalkanespiro‐4′‐imidazolidine‐2′,5′‐dithiones, namely cyclopentanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.4]nonane‐2,4‐dithione}, C7H10N2S2, cyclohexanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.5]decane‐2,4‐dithione}, C8H12N2S2, cycloheptanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.6]undecane‐2,4‐dithione}, C9H14N2S2, and cyclooctanespiro‐4′‐imidazolidine‐2′,5′‐dithione {systematic name: 1,3‐diazaspiro[4.7]dodecane‐2,4‐dithione}, C10H16N2S2, have been determined. The three‐dimensional packing in all of the structures is based on closely similar chains, in which hydantoin moieties are linked through N—H⋯S hydrogen bonding. The size of the cycloalkane moiety influences the degree of its deformation. In the cyclooctane compound, the cyclooctane ring assumes both boat–chair and boat–boat conformations. 相似文献
28.
M. V. Petrova T. V. Dorofeeva Yu. Yu. Popelis F. D. Polyak G. I. Zelchan 《Chemistry of Heterocyclic Compounds》1992,28(5):574-576
PMR spectra of 2-aryl- and 2-hetaryloxazolidines-1,3 are studied. A PMR criterion is revealed according to which the absolute configuration of the C(2) atom of the oxazolidine ring can be assigned.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 678–680, May, 1992. 相似文献
29.
J. Suloeva M. Jure E. Gudriniece M. Petrova A. Kemme 《Chemistry of Heterocyclic Compounds》2002,38(6):714-729
The alkylation, acylation, halogenation, nitration, oxidation, and hydrolysis reactions of 8-cyano-5-phenyl-7-trifluoromethyl-2,3-dihydroimidazo[1,2-a]pyridine have been studied. It was found that the 6-halo derivatives add alcohol to give covalent solvates. X-ray analysis has been carried out on one of the solvates (6-chloro-8-cyano-7-ethoxy-5-phenyl-7-trifluoromethyl-1,2,3,7-tetrahydroimidazo[1,2-a]pyridine) as well as on 8-cyano-5-phenyl-7-trifluoromethyl-2,3-dihydroimidazo[1,2-a]pyridine trifluoroacetate. 相似文献
30.
Boris A. Trofimov Ol’ga V. Petrova Lyubov’ N. Sobenina Igor’ A. Ushakov Al’bina I. Mikhaleva Yurii Yu. Rusakov Leonid B. Krivdin 《Tetrahedron letters》2006,47(22):3645-3648
Functionalized pyrrolic enols, 2-(2,2-dicyano-1-hydroxyethenyl)-1-methylpyrroles, synthesized from 2-ethenylpyrroles by a nucleophilic SEt-OH exchange, upon heating (75-142 °C) are readily rearranged to their 3-isomers in near to quantitative yield. The inter or intramolecular auto-protonation of a pyrrole ring by the acidic enol hydroxyl to form a mesomeric pyrrolium cation or zwitterion is suggested to be a key step in the rearrangement. 相似文献