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141.
142.
Georg Zocher Joachim Vilstrup Daniel Heine Asis Hallab Emilie Goralski Christian Hertweck Mark Stahl Till F. Sch?berle Thilo Stehle 《Chemical science》2015,6(11):6525-6536
Corallopyronin A is a polyketide derived from the myxobacterium Corallococcus coralloides with potent antibiotic features. The gene cluster responsible for the biosynthesis of corallopyronin A has been described recently, and it was proposed that CorB acts as a ketosynthase to interconnect two polyketide chains in a rare head-to-head condensation reaction. We determined the structure of CorB, the interconnecting polyketide synthase, to high resolution and found that CorB displays a thiolase fold. Site-directed mutagenesis showed that the catalytic triad consisting of a cysteine, a histidine and an asparagine is crucial for catalysis, and that this triad shares similarities with the triad found in HMG-CoA synthases. We synthesized a substrate mimic to derivatize purified CorB and confirmed substrate attachment by ESI-MS. Structural analysis of the complex yielded an electron density-based model for the polyketide chain and showed that the unusually wide, T-shaped active site is able to accommodate two polyketides simultaneously. Our structural analysis provides a platform for understanding the unusual head-to-head polyketide-interconnecting reaction catalyzed by CorB. 相似文献
143.
144.
Dr. Malika Makhlouf Brahmi Dr. Cyril Portmann Danilo D'Ambrosio Dr. Tom M. Woods Damiano Banfi Patrick Reichenbach Laeticia Da Silva Emilie Baudat Dr. Gerardo Turcatti Prof. Dr. Joachim Lingner Prof. Dr. Karl Gademann 《Chemistry (Weinheim an der Bergstrasse, Germany)》2013,19(14):4596-4601
By using the Telospot assay, 27 different extracts of cyanobacteria were evaluated for telomerase inhibition. All extracts showed varying, but significant activity. We selected Microcystis aeruguinosa PCC 7806 to identify the active compound and a bioassay guided fractionation led us to isolate mixtures of sulfoquinovosyl diacylglycerols (SQDGs), which were identified by 2D NMR and MS/MS experiments. Pure SQDG derivatives were then synthesized. The IC50 values of pure synthetic sulfoquinovosyl dipalmitoylglycerol and the monopalmitoylated derivative against telomerase were determined to be 17 and 40 μM , respectively. A structure–activity relationship study allowed the identification of compounds with modified lipophilic acyl groups that display improved activity. 相似文献
145.
Dr. Emilie David Gaëlle Milanole Pavel Ivashkin Dr. Samuel Couve‐Bonnaire Prof. Dr. Philippe Jubault Prof. Dr. Xavier Pannecoucke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(47):14904-14917
The combination of a fluorine atom and a cyclopropane ring, which both possess unique structural and chemical features, can generate new relevant building blocks for the discovery of efficient fluorinated biologically active agents. In this review, we report the different strategies to access monofluorocyclopropanes and highlight some of their attractive biological applications. 相似文献
146.
Daan van de Velde Soma Bahmany Emilie Hitzerd Bart van Domburg Jorie Versmissen A.H. Jan Danser Birgit C.P. Koch 《Biomedical chromatography : BMC》2020,34(3):e4787
Endothelin receptor antagonists (ERAs) such as, ambrisentan, macitentan and sitaxentan are primarily used for the treatment of pulmonary arterial hypertension. Considering the rise in endothelin in pre-eclampsia, ERAs may also be useful in its treatment. To evaluate the pharmacokinetics of ERAs, a rapid ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated to determine the concentration of ambrisentan, macitentan and sitaxentan in human plasma. Plasma samples were treated with methanol to induce protein precipitation. A chromatographic separation was performed on a C18 column using a gradient of methanol–water containing 0.1% formic acid and 0.013% ammonium acetate and a flow rate of 0.5 ml/min. Multiple reaction monitoring was used for quantification. This method was validated in a linear range of 20.28–2028 μg/l for ambrisentan, 4.052–405.2 μg/l for macitentan and 205.4–10 270 μg/l for sitaxentan. The method was successfully validated according to US Food and Drug Administration guidelines to determine the concentrations of macitentan, ambrisentan and sitaxentan in human plasma. This method is now being used for study samples and clinical patient samples. 相似文献
147.
Emilie‐Laure Zins Claude Pepe Detlef Schröder 《Journal of mass spectrometry : JMS》2010,45(7):740-749
Electrospray ionization (ESI) in combination with mass spectrometry (MS) experiments were carried out to study decameric uracil complexes cationized with Li+ ion. A previous study has shown that, under specific experimental conditions, a particularly intense peak of the decamer U10Li+ is formed, which was referred to as an indication for so‐called ‘magic number’ cluster. In order to gain more insight on the structure of this decameric complex, here, we report experimental studies concerning the kinetics of the fragmentation. In accordance with the new experimental data, structural models were constructed and fully optimized using ab initio and density functional theory quantum chemistry calculations. The theoretical study allowed us to propose a stable gas‐phase structure which is compatible with all experimental findings. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
148.
Stephanie Delbaere Elena V. Tulyakova Emilie Marmois Gediminas Jonusauskas Elena N. Gulakova Yuri V. Fedorov Olga A. Fedorova 《Tetrahedron》2013
We report here about effective FRET process (73–99%) in mono-Mg2+ complexes of symmetrical crown ether bis(styryl) dyes. The FRET process has not been observed in the free state and in binuclear complexes. The formation of mononuclear complex provides two styrylic fragments with appropriate positions of absorption and emission bands for FRET. The other important parameter for FRET is the proper geometric orientation of both chromophores, which attain sandwich conformation with close positioning of complexed and free styryl fragments induced by ion-modulated geometry reorganization of the bis-dye. 相似文献
149.
ChemInform Abstract: Structure,Properties, and Theoretical Electronic Structure of UCuOP and NpCuOP.
Daniel M. Wells Emilie Ringe D. Kaczorowski D. Gnida G. Andre Richard G. Haire Donald E. Ellis James A. Ibers 《ChemInform》2011,42(13):no-no
The title compounds are prepared by solid state reaction of U or Np, Cu and/or CuO, and P at 1073—1273 K (evacuated silica tube, 96 h). 相似文献
150.
Faure E Halusiak E Farina F Giamblanco N Motte C Poelman M Archambeau C Van de Weerdt C Martial J Jérôme C Duwez AS Detrembleur C 《Langmuir : the ACS journal of surfaces and colloids》2012,28(5):2971-2978
A facile and green approach is developed to impart remarkable protection against corrosion to galvanized steel. A protecting multilayer film is formed by alternating the deposition of a polycation bearing catechol groups, used as corrosion inhibitors, with clay that induces barrier properties. This coating does not affect the esthetical aspect of the surface and does not release any toxic molecules in the environment. 相似文献