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11.
Jesús Alberto Afonso Urich Viktoria Marko Katharina Boehm Raymar Andreína Lara García Dalibor Jeremic Amrit Paudel 《Molecules (Basel, Switzerland)》2021,26(21)
A novel and efficient stability-indicating, reverse phase ultra-performance liquid chromatographic (UPLC®) analytical method was developed and validated for the determination of hexoprenaline in an injectable dosage form. The development of the method was performed using analytical quality by design (AQbD) principles, which are aligned with the future requirements from the regulatory agencies using AQbD principles. The method was developed by assessing the impact of ion pairing, the chromatographic column, pH and gradient elution. The development was achieved with a Waters Acquity HSS T3 (50 × 2.1 mm i.d., 1.8 µm) column at ambient temperature, using sodium dihydrogen phosphate 5 mM + octane-1-sulphonic acid sodium salt 10 mM buffer pH 3.0 (Solution A) and acetonitrile (Solution B) as mobile phases in gradient elution (t = 0 min, 5% B; t = 1 min, 5% B; t = 5 min, 50% B; t = 7 min, 5% B; t = 10 min, 5% B) at a flow rate of 0.5 mL/min and UV detection of 280 nm. The linearity was proven for hexoprenaline over a concentration range of 3.50–6.50 µg/mL (R2 = 0.9998). Forced degradation studies were performed by subjecting the samples to hydrolytic (acid and base), oxidative, and thermal stress conditions. Standard solution stability was also performed. The proposed validated method was successfully used for the quantitative analysis of bulk, stability and injectable dosage form samples of the desired drug product. Using the AQbD principles, it is possible to generate methodologies with enhanced knowledge, which can eventually lead to a reduced regulatory risk, high quality data and lower operational costs. 相似文献
12.
Nicola Knetzger Viktoria Bachtin Susanne Lehmann Andreas Hensel Eva Liebau Fabian Herrmann 《Molecules (Basel, Switzerland)》2021,26(23)
In continuation of the search for new anthelmintic natural products, the study at hand investigated the nematicidal effects of the two naturally occurring quassinoids ailanthone and bruceine A against the reproductive system of the model nematode Caenorhabditis elegans to pinpoint their anthelmintic mode of action by the application of various microscopic techniques. Differential Interference Contrast (DIC) and the epifluorescence microscopy experiments used in the presented study indicated the genotoxic effects of the tested quassinoids (c ailanthone = 50 µM, c bruceine A = 100 µM) against the nuclei of the investigated gonadal and spermathecal tissues, leaving other morphological key features such as enterocytes or body wall muscle cells unimpaired. In order to gain nanoscopic insight into the morphology of the gonads as well as the considerably smaller spermathecae of C. elegans, an innovative protocol of polyethylene glycol embedding, ultra-sectioning, acridine orange staining, tissue identification by epifluorescence, and subsequent AFM-based ultrastructural data acquisition was applied. This sequence allowed the facile and fast assessment of the impact of quassinoid treatment not only on the gonadal but also on the considerably smaller spermathecal tissues of C. elegans. These first-time ultrastructural investigations on C. elegans gonads and spermathecae by AFM led to the identification of specific quassinoid-induced alterations to the nuclei of the reproductive tissues (e.g., highly condensed chromatin, impaired nuclear membrane morphology, as well as altered nucleolus morphology), altogether implying an apoptosis-like effect of ailanthone and bruceine A on the reproductive tissues of C. elegans. 相似文献
13.
Dr. Jakov Ivkovic Dr. Shalinee Jha Dipl.-Ing. Christian Lembacher-Fadum Dipl.-Ing. Johannes Puschnig Dr. Prashant Kumar Dr. Viktoria Reithofer Prof. Dr. Karl Gruber Prof. Dr. Peter Macheroux Prof. Dr. Rolf Breinbauer 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(56):14108-14120
Dipeptidyl peptidase III (DPP3) is a ubiquitously expressed Zn-dependent protease, which plays an important role in regulating endogenous peptide hormones, such as enkephalins or angiotensins. In previous biophysical studies, it could be shown that substrate binding is driven by a large entropic contribution due to the release of water molecules from the closing binding cleft. Here, the design, synthesis and biophysical characterization of peptidomimetic inhibitors is reported, using for the first time an hydroxyethylene transition-state mimetic for a metalloprotease. Efficient routes for the synthesis of both stereoisomers of the pseudopeptide core were developed, which allowed the synthesis of peptidomimetic inhibitors mimicking the VVYPW-motif of tynorphin. The best inhibitors inhibit DPP3 in the low μM range. Biophysical characterization by means of ITC measurement and X-ray crystallography confirm the unusual entropy-driven mode of binding. Stability assays demonstrated the desired stability of these inhibitors, which efficiently inhibited DPP3 in mouse brain homogenate. 相似文献
14.
Dr. Kai-Stephan Feichtner Dr. Lennart T. Scharf Dr. Thorsten Scherpf Dr. Bert Mallick Nils Boysen Prof. Dr. Viktoria H. Gessner 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(69):17351-17360
The use of iminophosphoryl-tethered ruthenium carbene complexes to activate secondary phosphine P−H bonds is reported. Complexes of type [(p-cymene)-RuC(SO2Ph)(PPh2NR)] (with R = SiMe3 or 4-C6H4−NO2) were found to exhibit different reactivities depending on the electronics of the applied phosphine and the substituent at the iminophosphoryl moiety. Hence, the electron-rich silyl-substituted complex undergoes cyclometallation or shift of the imine moiety after cooperative activation of the P−H bond across the M=C linkage, depending on the electronics of the applied phosphine. Deuteration experiments and computational studies proved that cyclometallation is initiated by the activation process at the M=C bond and triggered by the high electron density at the metal in the phosphido intermediates. Consistently, replacement of the trimethylsilyl (TMS) group by the electron-withdrawing 4-nitrophenyl substituent allowed the selective cooperative P−H activation to form stable activation products. 相似文献
15.
The complexation of ester betulin derivatives with (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD) was studied by mobility shift affinity CE. Electrophoretic mobility for triangular peaks was calculated using the parameter a1 of the Haarhoff–Van der Linde function instead of the peak top time. Dependences of the viscosity corrected electrophoretic mobility on HP-β-CD concentration were not described on the basis of only complexes with 1:1 stoichiometry due to the fact that these binding curves did not reach a plateau. However, the dependences were well described taking into account both 1:1 and 1:2 complexes. The presence of higher order equilibria was also revealed by x-reciprocal plots. The values of apparent binding constant logarithm, obtained for the first time, for 1:1 and 1:2 HP-β-CD complexes of betulin 3,28-diphthalate and betulin 3,28-disuccinate with 95% confidence interval limits in brackets are the same within error and are equal to 4.85 (4.73–4.95), 8.56 (7.75–8.82), 4.92 (4.86–4.97), and 8.54 (8.23–8.72) at 25°C, respectively. These values for 1:1 and 1:2 HP-β-CD complexes of betulin 3,28-disulfate at 25°C are 4.61 (4.57–4.64) and 7.11 (6.57–7.34), respectively. The binding constants for betulin 3,28-disulfate agree with the previously obtained results from the separation in the thermostatted capillary segment. 相似文献
16.
Beghin Luisa Knopova Viktoria P. Leonenko Nikolai N. Orsingher Enzo 《Journal of statistical physics》2000,99(3-4):769-781
We analyze the asymptotic behavior of the rescaled solution to the linear Korteweg–de Vries equation when the initial conditions are supposed to be random and weakly dependent. By means of the method of moments we prove the Gaussianity of the limiting process and we present its correlation function. The same technique is applied to the analysis of another third-order heat-type equation. 相似文献
17.
Svitlana R. Petrusenko Wolfgang Linert Viktoria V. Dyakonenko Oksana V. Nesterova Oleg V. Shishkin 《Acta Crystallographica. Section C, Structural Chemistry》2006,62(7):m281-m283
The title salt, [Zn(C2N2H8)3]2[CdI4]I2, conventionally abbreviated [Zn(en)3]2[CdI4]I2, where en is ethylenediamine, contains discrete [Zn(en)3]2+ cations and [CdI4]2− anions with distorted octahedral and nearly tetrahedral geometries, respectively, as well as uncoordinated I− ions. The cation and the free I− anion lie on twofold rotation axes and the [CdI4]2− anion lies on a axis in the space group I2d. The structure exhibits numerous weak inter‐ionic hydrogen bonds of two types, viz. N—H⋯I−(free ion) and N—H⋯I([CdI4]2−), which support the resulting three‐dimensional framework. 相似文献
18.
Oleg A. Filippov Andrey M. Filin Natalia V. Belkova Viktoria N. Tsupreva Yulia V. Shmyrova Igor B. Sivaev Lina M. Epstein Elena S. Shubina 《Journal of Molecular Structure》2006,790(1-3):114
Interaction of the salt (Ph3PNPPh3)BH3CN with the various OH and NH proton donors in low polar media was studied by variable temperature (200–290 K) IR spectroscopy and theoretically by DFT calculations. The formation of two types of complexes containing non-classical dihydrogen bond to the hydride hydrogen (DHB) and classical hydrogen bond (HB) to nitrogen lone pair was shown in solution. The 1:1 complexes of both types (XHH and XHN) coexist in the presence of equimolar amount of proton donor. The addition of excess XH-acid leads to the increase of the classical HB content and appearance of the 1:2 complexes, where two basic sites work simultaneously. The structure, spectral characteristics, energy and electron redistribution were studied by DFT (B3LYP) method. The comparison DHB parameters of [BH3CN]− with those of the unsubstituted analogue [BH4]− allowed analyzing the electronic effects of the CN group on the basic properties of boron hydride moiety. The electronic influence of the BH3 group on CN−HX hydrogen bond was also established by comparison with the corresponding classical HB to the CN− anion. 相似文献
19.
Sephadex LH-20 column chromatography was used to separate flavonoid components in a heartsease methanol extract. One of the
main components was identified by NMR as violanthin (6-C-glucosyl-8-C-rhamnosylapigenin). As a first approximation, the other main flavonoid component was considered to be rutin (3-O-rhamnoglucosylquercetin), based on comprehensive comparison of retention times and UV spectra of reference molecules, as
well as molecular mass and fragmentation patterns obtained by mass spectrometry. The minor flavonoids were separated by polyamide
column and analyzed by LC-MS. The antioxidant capacity of different flavonoid fractions was determined using both Trolox equivalent
antioxidant capacity (TEAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) in vitro antioxidant assays. The highest electron-donor
capacity was found for the major flavonoid component (rutin), whereas one minor component-rich flavonoid fraction exhibited
the highest hydrogen-donor activity. 相似文献
20.
Svetlana I. Pomogailo Gulzhian I. Dzhardimalieva Viktoria A. Ershova Sergei M. Aldoshin Anatolii D. Pomogailo 《Macromolecular Symposia》2002,186(1):155-160
Cluster metal-containing monomers were obtained and characterized. Mono- and disubstituted products were obtained under mild conditions via the interaction of Rh6(CO)16 with 4-vinylpyridine (4-VPy) in the presence of trimethylamin-N-oxide. Substitution of labile acetonitrile ligand in Rh6(CO)15NCMe by allyldiphenylphosphine (AlPPh2) yields Rh6(CO)14(μ,η2-PPh2CH2CH=CH2) with formation of π-complex. The structures of Rh6(CO)15(4-VPy), Rh6(CO)14(μ,η2-PPh2CH2CH=CH2) and (μ-H)Os3(μ-OCNM2)(CO)9PPH2CH2CH=CH2 have been determined by single-crystal X-ray diffraction studies, as well as by IR-, 1H NMR spectroscopies. The Rh - Rh bond lengths are within 2.72÷2.80 Å. The copolymerization of cluster-containing monomers synthesized with traditional monomers has been studied. It was found that Rh6- and Os3-containing monomers did not change either the ligand surroundings or the structure of cluster monomer framework during polymerization reaction. 相似文献