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111.
Silvana E. Vignaduzzo Luciana Vera-Candioti Patricia M. Castellano H��ctor C. Goicoechea Teodoro S. Kaufman 《Chromatographia》2011,74(7-8):609-617
A capillary zone electrophoresis method for the simultaneous determination of pridinol mesylate (PRI) and meloxicam (MEL) employing epinastine hydrochloride and piroxicam as internal standards, was developed and optimized employing experimental design and response surface methodologies. The separation was optimally achieved in less than 2 min at 30 kV in an uncoated fused-silica capillary (41.4 cm × 75 ??m I.D.), employing an 18 mmol L?1 sodium phosphate buffer solution (pH 5.90) at 25 °C. Samples were injected in hydrodynamic mode (50 mbar, 5 s) and the analytes were spectrophotometrically detected at 200 nm. Method robustness was demonstrated by ANOVA of determinations performed under conditions slightly different from the optimum. The method was validated regarding separation selectivity (peak purity factors > 0.99), linearity and range (PRI = 17.6?C31.4 mg L?1; MEL = 66.5?C122.5 mg L?1), accuracy (PRI = 100.2?C101.9%; MEL = 98.9?C100.7%) and precision. The RSD values obtained were ??1.3% for injection repeatability and ??1.9% for intra-day precision. The limits of detection (1.0 and 0.9 mg L?1) and quantification (3.3 and 16.5 mg L?1) of PRI and MEL, respectively, were also determined. The method was successfully applied to the determination of both drugs in three brands of tablet formulations. No statistically significant differences were observed when these results were compared with those of a RP-HPLC method. 相似文献
112.
Gabriela de Matuoka e Chiocchetti Elisabete A. De Nadai Fernandes Márcio Arruda Bacchi Rogério Augusto Pazim Silvana Regina Vicino Sarriés Thaís Melega Tomé 《Journal of Radioanalytical and Nuclear Chemistry》2013,297(3):399-404
Brazil is one of the largest producers of fruits cropping 40 million tons per year. In agro-food processing, approximately 50 % of raw material is discarded generating large amounts of by-products. The lack of information on the nutritional quality of agroindustrial by-products precludes their potential use in the manufacture of food products accessible to all. In this context, the objective of this work was to investigate the nutritional quality of by-products of the industrial processing of fruits. Samples of bagasse, peel and seeds of several fruits (banana, camu camu, coconut, cupuaçu, guava, jackfruit, mango, orange, papaya, pineapple, and soursop) were analysed by neutron activation analysis for the determination of Br, Ca, Co, Cr, Cs, Fe, K, La, Na, Rb, Sc and Zn. In general, higher levels of minerals were found in the by-products rather than in the pulps of fruits. This indicates that the use of the by-products should be encouraged, thereby reducing the economic and environmental impact of waste generated by agroindustrial processing. 相似文献
113.
Norma Sbarbati Nudelman Cecilia E. Silvana Alvaro 《Journal of Physical Organic Chemistry》2011,24(11):1067-1071
Inter‐ and intramolecular hydrogen bonding play an important role in determining the arrangement, physical properties, and reactivity of a great diversity of structures in chemical and biological systems. Several aromatic nucleophilic substitutions (ANS) in nonpolar aprotic, (non‐HBD), solvents recently studied in our laboratory have demonstrated the importance of self‐association of amines by hydrogen‐bond interactions. In this paper, we describe 1H‐NMR studies carried out at room temperature on bi‐ and polyfunctionalized amines, namely: N‐(3‐amino‐1‐propyl)morpholine (3‐APMo), histamine, 2‐guanidinobenzimidazole (2‐GB), 1,2‐diaminoethane (EDA), 3‐dimethylamino‐l‐propylamine (DMPA), and 1‐(2‐aminoethyl)piperidine (2‐AEPip). By 1H‐NMR measurements of amine solutions at variable concentrations we have shown that 3‐APMo, histamine and 2‐GB are able to form a six‐membered ring by intramolecular hydrogen bonding, while EDA, DMPA, and 2‐AEPip form dimers by intermolecular hydrogen bonds. Likewise, variable concentration 1H‐NMR studies allowed estimation of the corresponding equilibrium constants for the dimerization. These results are correlated with experimental kinetic results of ANS, confirming hereto the relevance of the “dimer mechanism” in reactions involving these amines. Copyright © 2011 John Wiley & Sons, Ltd. 相似文献
114.
Romualdo Caputo Carla Ferreri Luigi Longobardo Domenico Mastroianni Giovanni Palumbo Silvana Pedatella 《合成通讯》2013,43(9):1223-1229
A new high yielding coupling reaction of C-2 monosubstituted 5,6-dihydro-1,4-dithiins with aldehydes is reported. In this way allylic alcohols having the cis-substituted double bond tied up by a sulfur-containing ring can be readily prepared. Subsequent stereoselective sulfur removal then affords allylic alcohols with cis-configurated double bond. 相似文献
115.
It is known that tilting classes are of finite type, while cotilting classes are not always of cofinite type. We investigate this phenomenon. By using a bijection between definable classes of left modules and definable classes of right modules, we prove that it reflects the asymmetry existing between the notions of covers and envelopes or, otherwise stated, right and left approximations.In particular we show that there exist definable torsion classes containing the injective modules which are not tilting classes. 相似文献
116.
Silvana Franciosi Francesco de Giovanni 《Rendiconti del Circolo Matematico di Palermo》1996,45(2):256-266
In this article groups are investigated in which every infinite subnormal subgroup has finitely many conjugates or has finite index in its normal closure. 相似文献
117.
Francesco De Giovanni Silvana Franciosi 《Rendiconti del Circolo Matematico di Palermo》1982,31(2):257-266
Lower-modular infinite groups are considered in this paper. We give a generalization of a theorem of Jones and Ito to locally finite groups and to nilpotent-by-abelian groups; moreover we study periodic subgroups of lower-modular groups. 相似文献
118.
Archiv der Mathematik - 相似文献
119.
120.
The van der Waals dispersion coefficients of a set of polycyclic aromatic hydrocarbons, ranging in size from the single-cycle benzene to circumovalene (C(66)H(20)), are calculated with a real-time propagation approach to time-dependent density functional theory (TDDFT). In the nonretarded regime, the Casimir-Polder integral is employed to obtain C(6), once the dynamic polarizabilities have been computed at imaginary frequencies with TDDFT. On the other hand, the numerical coefficient that characterizes the fully retarded regime is obtained from the static polarizabilities. This ab initio strategy has favorable scaling with the size of the system--as demonstrated by the size of the reported molecules--and can be easily extended to obtain higher order van der Waals coefficients. 相似文献