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81.
Abstract A simple and sensitive spectrophotometric method is described for the determination of buclizine hydrochloride in bulk and tablets form. The method is based on the formation of charge-transfer complex between buclizine, as n-donor, and iodine, as Δ acceptor, which measured spectrophotometrically at 295 and 355 nm. A Job's plot indicated a 1:1 complex between the drug and iodine and Beer's law was obeyed in a concentration range of 4–30 μg ml?1. A more detailed investigation of the complex was made with respect to its association constant and the free energy change. The method is simple and sensitive and has been applied successfully to the analysis of laboratory-made tablets without any interference from the tablet excipients. To validate the method, the results obtained were compared statistically with a newly developed uv-derivative spectrophotometric method. The charge-transfer method was favored due to its higher sensitivity, cheap coast and available equipments. 相似文献
82.
Abdel‐Sattar S. Hamad Elgazwy 《应用有机金属化学》2007,21(12):1041-1053
Reactions of 2,5‐dibromothiophene, 1 , with [Pd2(dba)3]?dba [Pd(dba)2; dba = dibenzylideneacetone] in the presence of N‐donor ligands such as 2,2′‐bipyridine (bpy) and 4,4′‐di‐tert‐butyl‐2,2′‐bipyridine (dtbbpy) give arylpalladium complexes of cis‐[2‐(5‐BrC4H2S)PdBrL2], 2a, b [L2 = bpy ( 2a ), L2 = dtbbpy ( 2b )], and cis‐cis‐L2PdBr[2,5‐(C4H2S‐)PdBr(L2)], 3a, b [L2 = bpy ( 3a ), L2 = dtbbpy ( 3b )]. Treatment of cis complexes 2a, b and 3a, b with CO causes the insertion of CO into the Pd? C bond to give the aroyl derivatives of palladium complexes of cis‐[2‐(5‐BrC4H2S)COPdBrL2], 4a, b [L2 = bpy ( 4a ), L2 = dtbbpy ( 4b )], and cis‐cis‐[(L2)(CO)BrPdC4H2S‐PdBr(CO)(L2)], 5a, b [L2 = bpy ( 5a ) and L2 = dtbbpy ( 5b )], respectively. Treating complexes 2a, b with 1 mole equivalent of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) gave iminoacyl complexes cis‐[2‐(5‐BrC4H2S)C?NXyPdBrL2], 6a, b [L2 = bpy ( 6a ), L2 = dtbbpy ( 6b )], and a 3‐fold excess of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) gave triiminoacyl complexes [2‐(5‐BrC4H2S)(C?NXy)3 PdBr], 7 . Cyclization reactions of 6a, b with 3 mole equivalents of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) or cyclization reaction of 7 with 1 mole equivalent of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) both gave tetraiminoacyl complexes of [2‐(5‐BrC4H2S)(C?NXy)4PdBr], 8 , which was also obtained by the reaction of 1 or 2a, b with a 4‐fold excess of isocyanide XyNC with or without add Pd(dba)2. Similarly, complexes 3a and b were also reacted with 2 mole equivalents of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) to give iminoacyl complexes cis‐cis‐[(L2)(CNXy)BrPdC4H2S‐PdBr(CNXy)(L2)], 10a, b [L2 = bpy ( 10a ), L2 = dtbbpy ( 10b )] and an 8‐fold excess of isocyanide XyNC (Xy = 2,6‐dimethylphenyl) afforded tetraiminoacyl complexes of [2,5‐(C4H2S)(C?NXy)8Pd2Br2], 11 . Complexes 2a, b and 3a, b reacted with TlOTf [(TfO = CF3SO3)] in CH2Cl2 to give 9a, b and 12a, b , respectively, in a moderate yield. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
83.
84.
Nosrat Mustafa Abed Ebtisam Abdel Aziz Hafez Nadia Sobhy Ibrahim Mohamed Elsaid Mustafa 《Monatshefte für Chemie / Chemical Monthly》1985,116(2):223-228
The behaviour of 3,5-diamino-4-phenylazopyrazole toward a variety of reagents is reported. Several new 3,5-diaminopyrazole derivatives as well as amino derivatives of fused pyrazoles have been prepared.
Untersuchungen an 3,5-Diaminopyrazol-Derivaten
Zusammenfassung Es wird über das Verhalten von 3,5-Diamino-4-phenylazopyrazol gegenüber verschiedenen Agentien berichtet. Es wurden sowohl einige neue 3,5-Diaminooyrazol-Derivate als auch einige Aminoderivate von kondensierten Pyrazolen dargestellt.相似文献
85.
The prototropic rearrangement of 3-phenyl-1-propenes to the corresponding 1-phenyl-1-propenes was investigated in basic media utilizing 0.1M sodium ethoxide in absolute ethanol at 81°C. It was found that the effect of substituents on the rate of such isomerizations follows the order: p-NO2 > o-Cl > m-Cl ≥ m-F > p-Br > o-CH3 > m-CH3 > m-CH(CH3)2 > p-CH(CH3)2 ≥ p-C(CH3)3 > o-OCH3. This is consistent with first-order kinetics and “BS” mechanism. Quantitative treatment in terms of Hammett's equation showed a straight line, with a slope (p value) of +2.25. An increase in the strength of the base was also found to cause an increase in the rate of isomerization. 相似文献
86.
Two simple, precise, inexpensive and sensitive voltammetric methods for the determination of lomefloxacin (LFX), sparfloxacin hydrochloride (SFX), gatifloxacin (GFX), and moxifloxacin (MFX) were developed. The present methods were first used to explore the adsorption behavior of the four investigated antibacterial agents at a hanging mercury dropping electrode (HMDE), by a direct method and secondly by a modification via their complexation with PdCl(2). For the direct method, drugs were accumulated on HMDE, and a well-defined reduction peak was obtained in Britton-Robinson buffer of pH 7 for LFX and SFX, and pH 6 for GFX and MFX. The adsorptive stripping response was evaluated as a function of some variables such as the scan rate, pH, accumulation time and potential. For the modified method, the adsorptive behavior of Pd(II)-4-quinolone complexes at the HMDE developed a strippining voltammetry peak at a more negative potential than that of the free Pd(II) ions (-1.05 V). The limits of detection (LOD) were 2 x 10(-8) M, while the limits of quantification (LOQ) were 6 x 10(-8) M for the investigated drugs. The methods were applied to the determination of LFX, SFX, GFX, and MFX in biological samples and pharmaceutical preparations, and also compared with the official reference methods. Complete validation of the proposed methods was also done. 相似文献
87.
Hafez S. Abdel Wahab J. Bérczi L. Bognár G. Keömley 《Journal of Radioanalytical and Nuclear Chemistry》1977,36(2):479-490
Twelve zircon samples representing different genetic types from Australia, China, Egypt, Hungary, Korea and Nigeria were examined
using the neutron activation techniques. The study of the trace elements encountered in zircons, especially Zr/Hf ratios,
shed the light on the type of zircon minerals as well as the mother rock from which zircons wrre separated. Furthermore, the
effect of the secondary processes on zircons and their host rocks were also studied. 相似文献
88.
Zusammenfassung Es wird ein zweites graphisches Verfahren dargestellt, welches gestattet, die Viskosität zäher Flüssigkeiten zu ermitteln. 相似文献
89.
Excitation functions for proton elastic scattering on Mn55 at proton energies from 1320 KeV to 1480 KeV have been measured at the angles 135° and 150°. Anomalies in the differential elastic scattering were observed at Ep = 1350 ± 4 KeV, 1385 ± 4 KeV and 1445 ± 4 KeV respectively. These resonance states are the isobaric analogues of the ground, first excited and second excited states in Mn56 respectively. Analysis of the results showed that these resonance states are best fitted to a Jπ = 3+, 2+ and 1+ which is in excellent agreement with the Jπ values of the corresponding states in Mn56. The total widths and proton widths of these states were determined. 相似文献
90.