全文获取类型
收费全文 | 157篇 |
免费 | 9篇 |
专业分类
化学 | 116篇 |
晶体学 | 3篇 |
力学 | 5篇 |
数学 | 26篇 |
物理学 | 16篇 |
出版年
2023年 | 1篇 |
2022年 | 2篇 |
2021年 | 2篇 |
2020年 | 3篇 |
2019年 | 4篇 |
2017年 | 4篇 |
2016年 | 6篇 |
2015年 | 3篇 |
2014年 | 7篇 |
2013年 | 12篇 |
2012年 | 6篇 |
2011年 | 24篇 |
2010年 | 7篇 |
2009年 | 9篇 |
2008年 | 7篇 |
2007年 | 8篇 |
2006年 | 2篇 |
2005年 | 5篇 |
2004年 | 3篇 |
2003年 | 5篇 |
2002年 | 9篇 |
2001年 | 2篇 |
2000年 | 5篇 |
1998年 | 1篇 |
1997年 | 3篇 |
1996年 | 2篇 |
1995年 | 1篇 |
1993年 | 3篇 |
1992年 | 2篇 |
1989年 | 2篇 |
1985年 | 2篇 |
1983年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 3篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
排序方式: 共有166条查询结果,搜索用时 27 毫秒
21.
Jade Dussart-Gautheret Julia Deschamp Thibaut Legigan Maelle Monteil Evelyne Migianu-Griffoni Marc Lecouvey 《Molecules (Basel, Switzerland)》2021,26(24)
This paper reports on the synthesis of new hydroxymethylene-(phosphinyl)phosphonates (HMPPs). A methodology has been developed to propose an optimized one-pot procedure without any intermediate purifications. Various aliphatic and (hetero)aromatic HMPPs were synthesized in good to excellent yields (53–98%) and the influence of electron withdrawing/donating group substitution on aromatic substrates was studied. In addition, the one-pot synthesis of HMPP was monitored by 31P NMR spectroscopy, allowing effective control of the end of the reaction and identification of all phosphorylated intermediate species, which enabled us to propose a reaction mechanism. Optimized experimental conditions were applied to the preparation of biological relevant aminoalkyl-HMPPs. A preliminary study of the complexation to hydroxyapatite (bone matrix) was carried out in order to verify its lower affinity towards bone compared to bisphosphonate molecules. Moreover, in vitro anti-tumor activity study revealed encouraging antiproliferative activities on three human cancer cell lines (breast, pancreas and lung). 相似文献
22.
The inverse-gated-decoupling sequence enables quantitative (1)H decoupled (13)C spectra to be obtained. We modified this sequence so as to obtain the same result in less time for molecules containing carbons with various relaxation properties. For that, we determined the optimal (13)C longitudinal-magnetization initial value for a faster relaxation while (1)H decoupler is stopped. This value can be calculated precisely via the nuclear Overhauser effects, the longitudinal relaxation times, together with the determination of the relaxation rate constants of carbons while (1)H are out of equilibrium. A supplementary delay of (1)H decoupling and/or a series of selective pulses applied at the beginning of the recovery delay allow an acceleration of (13)C longitudinal relaxation. We applied this method to the molecule of vanillin. The simultaneous quantification of all carbons was carried out with a recovery delay divided by two compared to the usual sequence. 相似文献
23.
24.
Nathalie Poulain Evelyne Nakache Annabelle Pina Guy Levesque 《Journal of polymer science. Part A, Polymer chemistry》1996,34(5):729-737
The polymerization of isodecyl acrylate (ISODAC) in vesicles made from an anionic surfactant—sodium di-2-ethylhexyl phosphate (SEHP)—and from water is studied by 1H-NMR, transmission electron microscopy, and quasielastic light scattering. High polymerization rates and high conversion rates are achieved with both water-soluble initiator, K2S2O8 (potassium persulfate), and oil-soluble initiator, AIBN (azoisobisbutyronitrile). ISODAC is probably located inside the vesicle bilayer(s) because of its high hydrophobicity. Particles stable at room temperature with a mean diameter of about 50 nm are obtained. Kinetic orders of ISODAC polymerization are determined and the characterization of the resulting particles during and after polymerization are studied. © 1996 John Wiley & Sons, Inc. 相似文献
25.
26.
Evelyne Bernadac 《Journal of Theoretical Probability》1995,8(2):221-259
In this paper we introduce the inverse Gaussian and Wishart distributions on the cone of real (n, n) symmetric positive definite matricesH
n
+
() and more generally on an irreducible symmetric coneC. Then we study the convergence of random continued fractions onH
n
+
() andC by means of real Lagrangians forH
n
+
() and by new algebraic identities on symmetric cones forC. Finally we get a characterization of the inverse Gaussian distribution onH
n
+
() andC. 相似文献
27.
Methods for the preparation of various 1-hydroxy-1,1-bisphosphonate partial esters were developed. They were obtained from (alkyl or phenyl) bis(trimethylsilyl) phosphite and aromatic or aliphatic acid chlorides, followed by methanolysis. 相似文献
28.
The synthesis of the marine alkaloid sebastianine A and of a regioisomer has been accomplished via hetero-Diels-Alder reaction of indole-4,7-dione or N-tosylindole-4,7-dione with trifluoroacetamidocinnamaldehyde dimethylhydrazone, and subsequent cyclisation in alkaline conditions. 相似文献
29.
Jean M. J. Tronchet Guido Zosimo-landolfo Nicoletta Bizzozero Daniel Cabrini Ford Habashi Evelyne Jean 《Journal of carbohydrate chemistry》2013,32(1):169-186
Abstract Reduction of sugar aldoximes gave in good yield the corresponding terminal deoxy hydroxyamino sugars. These compounds were found to be reasonably stable (they could be kept for some weeks at 4° C). On standing in the air, these compounds in solution were spontaneously oxidized to the corresponding nitroxide free radicals whose ESR spectra gave useful structural information. 相似文献
30.
Veronique Sinou Julien Fiot Nicolas Taudon Joël Mosnier Maryse Martelloni Sok S. Bun Daniel Parzy Evelyne Ollivier 《Journal of separation science》2010,33(12):1863-1869
In Africa, Mitragyna inermis (Willd.) O. Kuntze (Rubiaceae) is commonly used in traditional medicine to treat malaria. Antimalarial activity is mostly due to the hydromethanolic extract of M. inermis leaves and especially to the main alkaloids, uncarine D and isorhynchophilline. In the present study, we describe for the first time an HPLC method for the simultaneous quantification of uncarine D and isorhynchophylline in biological matrices. SPE was used to extract the components and the internal standard naphthalene from human and pig plasma samples. Chromatographic separation was performed on a C‐18 reversed column at a flow rate of 1 mL/min, using methanol–phosphate buffer (10:90, pH 7), as a mobile phase. Good linearity was observed over the concentration ranges of 0.0662–3.31 μg/mL for uncarine D and 0.0476–2.38 μg/mL for isorynchophylline. The precision was less than 12% and the accuracy was from 86 to 107% without any discrepancy between the two species. Uncarine D and isorhynchophylline recoveries were over 80%. These results allowed the quantification of both uncarine D and isorhynchophylline in pig plasma after intravenous administration of M. inermis extract. 相似文献