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111.
Andreas Rahm Evgeni M. Kaidashev Heidemarie Schmidt Mariana Diaconu Andreas Pöppl Rolf Böttcher Christoph Meinecke Tilman Butz Michael Lorenz Marius Grundmann 《Mikrochimica acta》2006,153(1-2):21-25
A flow injection chemiluminescence method is proposed for the determination of cobalt, based on the strong catalytic effect
of Cobalt(II) (1,10-phenanthroline)3 complex on the lucigenin-periodate reaction in alkaline medium. Under the optimum experimental conditions, the chemiluminescence
signal responded linearly to the concentration of cobalt(II) in the 1.0 × 10−9–3.0 × 10−7 g mL−1 range with a detection limit of 4.4 × 10−10 g mL−1 cobalt(II). The relative standard deviation for the determination of 5.0 × 10−8 g mL−1 of cobalt was 2.3% in eleven replicated measurements. The method was successfully applied to the determination of cobalt(II)
in pharmaceutical preparations. 相似文献
112.
Hans Fritz Rolf Gleiter Michel Nastasi Jean-Luc Schuppiser Jacques Streith 《Helvetica chimica acta》1978,61(8):2887-2898
3-Substituted 1-iminopyridinium ylides 1 undergo photo-induced ring enlargement to 1H-1,2-diazepines. With strongly electron-withdrawing substituents the ring expansion process is regiospecific and leads exclusively to 4-substituted 1 H-1, 2-diazepines. Weak electron-donating substituents, like a methyl group and halogen atoms, do not have any directing effect since both 4- and 6-substituted 1 H -1,2-diazepines are obtained. With strong electron-donating substituents no diazepines are formed; instead one observes photo-induced isomerization to the 2-aminopyridine derivatives, the process being non-regiospecific. Regiospecific photo-induced ring expansion processes are explained in terms of a simple HMO model. 相似文献
113.
Mohammad A. Hai Nigel W. Preston Rolf Kyburz Emanuel Schpp I. Ralph C. Bick Manfred Hesse 《Helvetica chimica acta》1980,63(7):2130-2134
Aristoserratine, a New Indole Alkaloid from Aristotelia serrata W.R.B. OLIVER and from A. peduncularis (LABILL .) HOOK . F. The new indole alkaloid aristoserratine (2) has been isolated from Aristotelia. Its structure and absolute configuration were elucidated on the basis of spectroscopic data. 相似文献
114.
Hans-Peter Ros Rolf Kyburz Nigel W. Preston Rex T. Gallagher I. Ralph C. Bick Manfred Hesse 《Helvetica chimica acta》1979,62(2):481-487
The revised structure 1 is put forward for peduncularine, the main alkaloid of Aristotelia peduncularis (Labill.) HOOK. F. (Elaeocarpaceae), on the basis of its spectroscopic properties and those of its degradation products, the Hofmann base 3 and the hydrogenation product 4 . Structure 1 represents the relative configuration of the alkaloid. Peduncularine belongs to the class of indole alkaloids with a monoterpene unit as the aliphatic portion. To our knowledge it constitutes the first example in which an isopropyl group has become detached from the terpene unit and occurs as a substituent on nitrogen. 相似文献
115.
Sensitized photo-oxidation of methylcyclohexane as a thin film on seawater by irradiation with natural sunlight 总被引:1,自引:0,他引:1
Methylcyclohexane dissolved in and forming a thin film on purified seawater with traces of anthraquinone added as triplet sensitizer was exposed to natural sunlight in a quartz flask. The water was circulated through a glass cartridge filled with Amberlite XAD-2 for the concentration of reaction products which were identified by GC/MS after elution and silica gel chromatography. They included isomeric methylcyclohexanols as the principal components, primary hydroperoxides, a tentatively identified secondary peroxide, methylcyclohexanones, and acyclic ketones. Mass spectra and mechanisms are discussed as well as possible biological consequences of the formation of these compounds. 相似文献
116.
Summary The azo dyes eriochrome black T, eriochrome blueblack R and eriochrome blueblack B and their complexes with cobalt, manganese and magnesium show adsorption enrichment on carbon paste electrodes, dependent on the composition of the electrode filling. This effect may be used for the determination of cobalt and manganese by a.c. voltammetry in the 10–7 to 10–6 M range. Standard deviation has been found to be ± 3.2 and ± 3.5%, respectively.
Adsorptive Anreicherung einiger Komplexe von Azofarbstoffen an einer Kohlepasteelektrode. Anwendung zur Bestimmung geringer Konzentrationen von Kobalt und Mangan
Zusammenfassung Die Azofarbstoffe Eriochromschwarz T, Eriochromblauschwarz B und Eriochromblauschwarz R sowie ihre Komplexe mit Kobalt, Mangan und Magnesium werden adsorptiv an Kohlepasteelektroden angereichert. Die Anreicherung ist von der Zusammensetzung der Elektrodenfüllung abhängig. Anwendungen zur wechselstromvoltammetrischen Bestimmung von Kobalt und Mangan im 10–7 bis 10–6 M Bereich werden beschrieben. Die Standardabweichung liegt bei ± 3,2 bzw. ± 3,5%.
Die Untersuchungen wurden in dankenswerter Weise durch Mittel der Deutschen Forschungsgemeinschaft und des Verbandes der chemischen Industrie unterstützt. 相似文献
117.
118.
Saalfrank RW Glaser H Demleitner B Hampel F Chowdhry MM Schünemann V Trautwein AX Vaughan GB Yeh R Davis AV Raymond KN 《Chemistry (Weinheim an der Bergstrasse, Germany)》2002,8(2):493-497
In a one-pot reaction, the tetranuclear iron chelate complex [Fe4(L4)4] 6 was generated from benzene-1,3,5-tricarboxylic acid trichloride (4), bis-tert-butyl malonate (5a), methyllithium, and iron(II) dichloride under aerobic conditions. Alternatively, hexanuclear iron chelate complex [Fe(L5)6] 7 was formed starting from bis-para-tolyl malonate (5b) by employing identical reaction conditions to those applied for the synthesis of 6. The clusters 6 and 7 are present as racemic mixtures of homoconfigurational (delta,delta,delta,delta)/(lambda,lambda,lambda,lambda)-fac or (delta,delta,delta,delta,delta,delta)/(lambda,lambda,lambda,lambda,lambda,lambda)-fac stereoisomers. The structures of 6 and 7 were unequivocally resolved by single-crystal X-ray analyses. The all-iron(III) character of 6 and 7 was determined by M?ssbauer spectroscopy. 相似文献
119.
The two new compounds [Fe(tren)]FeSbS4 ( 1 ) (tren = tris(2‐aminoethyl)amine) and [Fe(dien)2]Fe2Sb4S10 ( 2 ) (dien = diethylendiamine) were prepared under solvothermal conditions and represent the first thioantimonates(III) with iron cations integrated into the anionic network. In both compounds Fe3+ is part of a [2FeIII‐2S] cluster which is often found in ferredoxines. In addition, Fe2+ ions are present which are surrounded by the organic ligands. In ( 1 ) the Fe2+ ion is also part of the thioantimonate(III) network whereas in ( 2 ) the Fe2+ ion is isolated. In both compounds the primary SbS3 units are interconnected into one‐dimensional chains. The mixed‐valent character of [Fe(tren)]FeSbS4 was unambiguously determined with Mössbauer spectroscopy. Both compounds exhibit paramagnetic behaviour and for ( 1 ) a deviation from linearity is observed due to a strong zero‐field splitting. Both compounds decompose in one single step. 相似文献
120.
Markus Neuenschwander Peter Bigler Klaus Christen Rudolf Iseli Rolf Kyburz Hansueli Mühle 《Helvetica chimica acta》1978,61(6):2047-2058
Chloroacylation and bromoacylation of carbonyl compounds: A forgotten carbonyl reaction. I. Scope of the reaction Aliphatic, α,β-unsaturated and aromatic aldehydes as well as aliphatic ketones react with acyl halides to (α-haloalkyl)esters. These bifunctional derivates contain two leaving groups of different reactivity. The scope of this scarcely of this scarcely known carbonyl reaction is discussed. 相似文献