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661.
In this study, certain 3‐substituted styrylquinoxalin‐2(1H)‐ones ( 2a‐d ) and their 2‐chloro ( 3a‐d ) and 2‐piperazinyl derivatives ( 4a‐g ) were synthesized from 3‐methylquinoxalin‐2(1H)‐one ( 1 ). In addition, a series of 1‐alkyl‐3‐substituted styrylquinoxalin‐2(1H)‐ones ( 5a‐d ) was also prepared. Moreover, 3‐(N2‐arylidenehydrazinocarbonyl)quinoxalin‐2(1H)‐ones ( 8a‐c ) as well as their cyclized oxadiazolinyl derivatives ( 9a‐c ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Furthermore, 3‐(5‐substituted thio‐1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐ones ( 11a‐c ) and ( 12a‐c ) were obtained from the intermediate compound ( 10 ) ‐ previously obtained via cyclization of ( 7 ) with CS2. Likewise, 3‐(5‐oxo‐4,5‐dihydro‐(1,3,4‐oxadiazol‐2‐yl)quinoxalin‐2(1H)‐one ( 13 ), 3‐[5‐(4‐nitrophenyl)‐1,3,4‐oxadiazol‐2‐yl]‐quinoxalin‐2(1H)‐one ( 14 ) and its 2‐chloro derivative ( 15 ) were prepared from 3‐hydrazinocarbonylquinoxalin‐2(1H)‐one ( 7 ). Some of these derivatives were evaluated for antimicrobial activity in vitro and some of the tested compounds showed antibacterial or antifungal activity. 相似文献
662.
Generic simple and sensitive universal enzyme immunoassay approach for the determination of small analytes has been developed to avert the problems associated with small molecule immobilization onto solid phases. The developed assay employed a heterogeneous non-competitive binding format. The assay used anti-analyte antibody coupled to polyacrylamide beads as a solid-phase and β-d-galactosidase enzyme-labeled analyte as a label. In this assay, the analyte in a sample was firstly incubated to react with an excess of the antibody-coupled beads, and then the unoccupied antibody binding sites were allowed to react with the enzyme-labeled analyte. Analyte bound to the antibody-coupled beads was separated by centrifugation, and the enzyme activity of the supernatant was measured spectrophotometrically at 420 nm, after reaction with 4-nitrophenyl-β-d-galactopyranoside as a substrate for the enzyme. The signal was directly proportional to the concentration of analyte in the sample. The optimum conditions for the developed assay were established and applied to the determination of tobramycin, as a representative example of the small analytes, in serum samples. The assay limit of detection was 10 ng mL−1 and the effective working range at relative standard deviation of ≤10% was 40-800 ng mL−1. The assay precisions were acceptable; the relative standard deviations were 4.36-5.17 and 5.62-7.40% for intra- and inter-assay precision, respectively. Analytical recovery of tobramycin spiked in serum ranged from 95.89 ± 4.25 to 103.45 ± 4.60%. The assay results correlated well with those obtained by high-performance liquid chromatography (r = 0.992). The assay described herein has great practical value in determination of small analytes because it is sensitive, rapid, and easy to perform in any laboratory. Although the assay was validated for tobramycin, however, it is also anticipated that the same methodology could be used for essentially any analyte for which a selective antibody exists, and an appropriate enzyme conjugate can be made. 相似文献
663.
Jabasini M Zhang L Dang F Xu F Almofli MR Ewis AA Lee J Nakahori Y Baba Y 《Electrophoresis》2002,23(10):1537-1542
Validation of microchip electrophoresis in DNA analysis has been carried out using an Agilent 2100 Bioanalyzer. With a DNA 500 Assay Kit, the reproducibility and accuracy of fragment sizing of a 10 bp DNA ladder have been shown to be satisfactory with the relative standard deviation and the relative error mostly below 1.0 and 5.0% (n = 12), respectively. Both intraday and interday validations of fragment sizing and quantitation have also been performed with a 7500 Assay Kit (n = 48). Although the results of quantitation are not as good as that of sizing, due to the manual introduction of samples and markers into the chip wells, they are still sufficient to carry out further analyses of practical samples. Based on such reliable results, fast analysis of DNA polymorphisms on the human Y-chromosome has been realized with microchip electrophoresis. The total analysis times of three genomic polymorphisms on the Y-chromosome, Y Alu polymorphism, 47z/StuI, and 12f2, are all within 100 s, and the relative standard deviation and relative error of fragment sizes are below 3.5 and 3.7%, respectively. In addition, a mixture of nine DNA markers on the human Y-chromosome related to examine the cause of spermatogenic failure have been separated successfully with the smallest fragment size difference of 7 bp. Our results demonstrate the potential of microchip electrophoresis in polymorphism analysis with the advantages of high speed, good reproducibility, high precision, and high resolution. 相似文献
664.
The present study accents on the privileges of microchip-based electrophoresis to the conventional gel electrophoresis in separation of telomerase repeat amplification protocol/polymerase chain reaction (PCR) ladder products obtained in telomerase-catalyzed reaction in cancer cells. We try to clarify the interpretation of the results obtained by both electrophoretic procedures and to avoid misinterpretation as a result of PCR-dependent artefacts. 相似文献
665.
M. Ashraf Chaudry Nighat Yasmin Noor-Ul-Islam 《Journal of Radioanalytical and Nuclear Chemistry》1989,129(2):409-423
V(V), Zn(II) and Be(II) have been studied to test oxine and tri-n-butylphosphate (TBP) as carriers for transport through supported liquid membranes in polypropylene film. All the three types of ions can be passed through such membranes using oxine in case of V(V) and TBP in case of Zn(II) and Be(II). Maximum flux of metal ions has been observed from 0.01M H2SO4 for V(V) (3.22·10–6 mol·m–2·s–1) and 2M HCl containing 3M CaCl2 for Zn(II) solution (1.4·10–6 mol·m–2·s–1). Low flux was observed in case of Be(II) since the membrane was affected by sulphocyanide group and did not remain hydrophobic. Mechanism of transport for these metal ions have been proposed separately. Distribution coefficient data for V(V) have also been evaluated to determine theoretical values of the permeability coefficient, and compared with experimental values. 相似文献
666.
Ahmed Abdullah Fazlul Huq Ashraf Chowdhury Hasan Tayyem Philip Beale Keith Fisher 《BMC chemical biology》2006,6(1):3-9
Background
Cis-planaramineplatinum(II) complexes like their trans isomers are often found to be active against cancer cell lines. The present study deals with the synthesis, characterization and determination of activity of new cis-planaramineplatinum(II) complexes. 相似文献667.
Nehad A. Abdel-Latif Nermien M. Sabry Ashraf M. Mohamed Mohamed M. Abdulla 《Monatshefte für Chemie / Chemical Monthly》2007,138(7):715-724
Summary. A series of substituted pyridine, pyrazoline, and thiopyrimidine derivatives were synthesized from 3-acetylpyridine, which
was prepared from nicotinic acid as a naturally starting material. The pharmacological screening showed that many of these
compounds have good analgesic and antiparkinsonian activities comparable to Voltarene? and Benzatropine? as reference drugs. The structure assignment of the new compounds is based on chemical and spectroscopic evidence. The detailed
synthesis, spectroscopic data, and pharmacological properties for synthesized compounds are reported. 相似文献
668.
R. Ashraf S. Shahzadi S. Ali M. H. Bhatti S. Yaqub F. Ahmad 《Russian Journal of Coordination Chemistry》2007,33(8):576-581
Different vanadium(IV) complexes of general formula VF2L2 have been synthesized, where L are various nonsteroidal antiinflammatory drugs. The complexes are characterized by elemental
analysis, UV-visible, and infrared spectroscopy. The metal contents estimated by the ICP-AES method in the synthesized complexes
are in good agreement with their calculated values and spectroscopic data proposed the octahedral geometry for the reported
complexes. Conductance measurements show the nonelectrolytic nature of complexes. Biological screening tests against different
bacteria and fungi show significant antibacterial and antifungal activity for all the complexes.
The article was submitted by the authors in English. 相似文献
669.
在不同温度下对液态水进行分子动力学模拟,研究各温度下液态水中各个原子的速度自相关函数密度谱,以考察液态水热容的量子校正随温度的变化规律.研究结果表明,水分子的三个内部振动模式对热容的量子校正不随温度变化,而转动和分子距平衡位置的摆动运动模式的量子校正随温度升高而逐步减小.对于分子动力学模拟结果经温度涨落计算所得的热容进行了量子校正,校正结果与实验值能符合. 相似文献
670.
A K Singh M Ashraf K Granley U Mishra M M Rao B Gordon 《Journal of chromatography. A》1989,473(1):215-226
A simple and reproducible column (Clean Screen-DAU, copolymeric bonded-phase silica column) extraction procedure has been described for the screening and confirmation of drugs in horse urine. The recovery of drugs by the column extraction was better than or comparable to the recovery by the liquid-liquid extraction, which is commonly used in the equine analytical laboratories. The column extraction provided broad coverage of drugs, separated extracts into three fractions (acidic/neutral, steroids, basic), produced a cleaner extract, and eliminated the need for special liquid-liquid extraction procedures for different drugs. The column extract was cleaner and did not contain impurities, whereas, the liquid-liquid extract was relatively impure and the extract required further thin-layer chromatographic cleanup. The column extraction procedure was used to confirm the presence of several potent drugs, such as fentanyl, etorphine, and mazindol. 相似文献