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51.
A simple, rapid and sensitive HPLC method was developed and validated for the determination of four tricyclic antidepressants (TCAs): amitriptyline, doxepin, clomipramine (CLO) and imipramine, in pharmaceutical formulations and biological fluids. A Kromasil C(8 )analytical column (250 x 4 mm, 5 microm) was used for the separation, with a mobile phase consisting of 0.05 M CH(3)COONH(4) and CH(3)CN (45:55 v/v) delivered at 1.5 mL/min isocratically. Quantification was performed at 238 nm, with bromazepam (1.5 ng/microL) as the internal standard. The determination of TCAs in blood plasma was performed after protein precipitation. Urine analysis was performed by means of SPE using Lichrolut RP-18 Merck cartridges providing high absolute recoveries (> 94%). Direct analysis of urine was also performed after two-fold dilution. The developed method was fully validated in terms of selectivity, linearity, accuracy, precision, stability and sensitivity. Repeatability (n = 5) and between-day precision (n = 5) revealed RSD <13%. Recoveries from biological samples ranged from 91.0 to 114.0%. The absolute detection limit of the method was calculated as 0.1-0.6 ng in blood plasma and 0.2-0.5 ng in extracted urine or 0.4-0.7 in diluted urine. The method was applied to real samples of plasma from a patient under CLO treatment. 相似文献
52.
In this paper, the application of polyethylene glycol (PEG) aqueous solution as a green solvent in microwave-assisted extraction (MAE) was firstly developed for the extraction of flavone and coumarin compounds from medicinal plants. The PEG solutions were optimized by a mono-factor test, and the other conditions of MAE including the size of sample, liquid/solid ratio, extraction temperature and extraction time were optimized by means of an orthogonal design L(9) (3(4)). Subsequently, PEG-MAE, organic solvent-MAE, and conventional heating reflux extraction (HRE) were evaluated with nevadensin extraction from Lysionotus pauciflorus, aesculin and aesculetin extraction from Cortex fraxini. Furthermore, the mechanism of PEG-MAE was investigated, including microwave-absorptive property and viscosity of PEG solutions, the kinetic mechanism of PEG-MAE and different microstructures of those samples before and after extraction. Under optimized conditions, the extraction yields of nevadensin from L. pauciflorus, aesculin and aesculetin from C. fraxini were 98.7%, 97.7% and 95.9% in a one-step extraction, respectively. The recoveries of nevadensin, aesculin and aesculetin were in the range of 92.0-103% with relative standard derivation lower than 3.6% by the proposed procedure. Compared with organic solvent-MAE and conventional extraction procedures, the proposed methods were effective and alternative for the extraction of flavone and coumarin compounds from medicinal plants. On the basis of the results, PEG solution as a green solvent in the MAE of active compounds from medicinal plants showed a great promising prospect. 相似文献
53.
54.
Krzysztof Kozak Beata Koz?owskaTadeusz A. Przylibski Jadwiga MazurAnna Adamczyk-Lorenc Kalina Mamont-Cie?laOlga Stawarz Jerzy DordaBarbara K?os Miros?aw JanikEl?bieta Kochowska 《Radiation measurements》2012,47(1):89-95
The paper presents the results of intercalibration measurements of 222Rn concentration in water samples. The aim of the experiments was to evaluate the different measurement methods of radon determination in water samples performed by eleven laboratories in Poland and to test these methods in field work. In the years 2001-2003 three national intercomparison experiments were organized. The results allowed the participating laboratories to improve their measurement methodologies and to achieve better, i.e. more convergent results of determining radon concentration in water samples. The results show that the use of liquid-scintillation technique seems to be the best measurement method. It should be emphasized that comparative experiments are essential for all laboratories and they should be carried out as often as possible, based both on prepared samples with known concentration values of 222Rn and natural water samples, the most commonly used in laboratory practice. 相似文献
55.
F. V. Sussa P. S. C. Silva S. R. Damatto D. I. T. Fávaro B. P. Mazzilli 《Journal of Radioanalytical and Nuclear Chemistry》2009,281(2):165-170
Since the early days of mankind, plants have been used as food and for medicinal purposes. Still, little information exists
in literature about the activity concentration of 238U and 232Th decay products, as well as stable element concentrations in Brazilian plants. Activity concentrations of 226Ra, 228Ra and 210Pb, and chemical concentrations of As, Ba, Br, Cs, Co, Cr, Cu, Eu, Fe, Hf, La, Lu, Rb, Sb, Sc, Sm, Ta, Tb, Yb, Zn and Zr were
determined in ten samples commonly used in Brazilian medicinal plants. 相似文献
56.
A convenient method to introduce a sulfone group to pyridines and diazines is described. This efficient method involves the conjugate addition of sodium methanesulfinate to vinyl heterocycles. This process tolerates a wide variety of functional groups and is performed in the presence of acetic or trifluoroacetic acid. A one-pot, two-step synthesis of sulfones starting from the corresponding heteroaryl halide is also described. 相似文献
57.
Application of ionic liquids in the microwave-assisted extraction of polyphenolic compounds from medicinal plants 总被引:1,自引:0,他引:1
Ionic liquids (ILs) solutions as solvents were successfully applied in the microwave-assisted extraction (MAE) of polyphenolic compounds from medicinal plants. ILs, its concentration and MAE conditions were investigated in order to extract polyphenolic compounds effectively from Psidium guajava Linn. (P. guajava) leaves and Smilax china (S. china) tubers. The results obtained indicated that the anions and cations of ILs had influences on the extraction of polyphenolic compounds as well as the ILs with electron-rich aromatic π-system enhanced extraction ability. Under the optimized conditions, the extraction yields of the polyphenolic compounds were in the range of 79.5-93.8% with one-step extraction, and meanwhile the recoveries were in the range of 85.2-103% with relative standard deviations (R.S.D.s) lower than 5.6%. Compared to conventional extraction procedures, the results suggested that the proposed method was effective and alternative for the extraction of polyphenolic compounds from medicinal plants. In addition, the extraction mechanisms and the structures of samples before and after extraction were also investigated. ILs solutions as green solvents in the MAE of polyphenolic compounds from medicinal plant samples showed a great promising prospect. 相似文献
58.
Approval of bortezomib has validated ubiquitin-proteasome pathway as an important target for treatment of haematological malignancies. However, clinical shortcomings of bortezomib, a covalent peptide proteasome inhibitor, has prompted a paradigm shift in anti-proteasome drug discovery towards development of non-peptidic inhibitors and targeting of upstream ubiquitin system which has drawn traction for interdisciplinary forays. It is being widely recognized that natural products provide valuable leads in the discovery of potent, chemically diverse, non-peptidic inhibitors of 20S proteasome and of key enzymes involved in ubiquitination machinery. As a result, total synthesis of natural, non-peptidic inhibitors of ubiquitin-proteasome pathway has emerged as a critical interlink between organic synthesis, medicinal chemistry, biochemical profiling and drug discovery. An up-to-date account of contextual synthetic challenges, strategies and accomplishments as well as mapping of the chemical diversity space around the natural scaffolds has been captured in this review. 相似文献
59.
Donogh J.R. OMahony Russell J. Johnson M. Angels Estiarte William T. Edwards Matthew A.J. Duncton 《Tetrahedron letters》2019,60(47):151229
A reliable three-step synthesis of ortho-substituted 4-pyrazolyl-2-ethylamines starting from a pyrazole methyl ketone and N-tert-butanesulfinylamine is described. Strongly dehydrating conditions were required to form the N-tert-butanesulfinyl ketimines, but these intermediates were stable to aqueous work-up and chromatography. Reduction of N-tert-butanesulfinyl ketimines with L-selectride®, or Super-hydride®, in THF afforded excellent yields and diastereoselectivities of the sulfinamides, which were converted into chiral amines with methanolic HCl. The 4-pyrazolyl-2-ethylamines from these investigations are attractive building blocks for medicinal chemists, as they exhibit low molecular weight, and low calculated octanol-water partition coefficient (c Log P values), while disrupting planarity with three-dimensional character. For example, the amine products were utilized in structure-activity studies of the human transient receptor potential vanilloid 1 (TRPV1/VR1). 相似文献
60.
本文研究了两种药液中钾、钠、钙、镁、铝、铁的测定方法,并讨论了元素间的光谱干扰及非光谱干扰的校正,获得满意结果。其回收率为90-118%,测量精度(RSD%)小于6%。 相似文献