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161.
Meier F Abeywardana T Dhall A Marotta NP Varkey J Langen R Chatterjee C Pratt MR 《Journal of the American Chemical Society》2012,134(12):5468-5471
The process of neurodegeneration in Parkinson's Disease is intimately associated with the aggregation of the protein α-synuclein into toxic oligomers and fibrils. Interestingly, many of these protein aggregates are found to be post-translationally modified by ubiquitin at several different lysine residues. However, the inability to generate homogeneously ubiquitin modified α-synuclein at each site has prevented the understanding of the specific biochemical consequences. We have used protein semisynthesis to generate nine site-specifically ubiquitin modified α-synuclein derivatives and have demonstrated that different ubiquitination sites have differential effects on α-synuclein aggregation. 相似文献
162.
Krzysztof Babiuch David Pretzel Tatiana Tolstik Antje Vollrath Sarmiza Stanca Franziska Foertsch C. Remzi Becer Michael Gottschaldt Christoph Biskup Ulrich S. Schubert 《Macromolecular bioscience》2012,12(9):1190-1199
Chain length, size, composition, surface charge, and other properties of polymeric materials affect their recognition and uptake by cells and must be optimized to deliver polymers selectively to their target. However, it is often not possible to precisely modify selected properties without changing other parameters. To overcome these difficulties, well‐defined poly(pentafluorostyrene)‐based polymers are prepared that can be grafted via thiol/para‐fluorine “click” reaction with 1‐thio‐β‐D ‐glucose and 1‐thio‐β‐D ‐galactose. Fluorescence microscopy and flow cytometry show that nanoparticles are taken up by HepG2 cells to a higher degree than the respective water‐soluble polymers, and that internalization of both galactosylated homo‐ and nanoprecipitated block copolymers is enhanced.
163.
Some mixed variational principles are presented for problems involving electro-elastic interactions, whereby the electric field follows from a scalar potential. Firstly, in order to set the stage, we consider the basic case of merely free space. Secondly, to increase the complexity, we immerse an electro-active but mechanically rigid body into vacuum. As our final goal we thirdly treat a geometrically non-linear deformable electro-elastic body that is surrounded by free space. Electro-elastic bodies are of particular interest since they can develop large elastic deformations as a response to the presence of electric fields. 相似文献
164.
165.
Samer Haidar Franziska M. Jürgens Dagmar Aichele Annika Jagels Hans-Ulrich Humpf Joachim Jose 《Molecules (Basel, Switzerland)》2021,26(15)
A large number of secondary metabolites have been isolated from the filamentous fungus Stachybotrys chartarum and have been described before. Fourteen of these natural compounds were evaluated in vitro in the present study for their inhibitory activity towards the cancer target CK2. Among these compounds, stachybotrychromene C, stachybotrydial acetate and acetoxystachybotrydial acetate turned out to be potent inhibitors with IC50 values of 0.32 µM, 0.69 µM and 1.86 µM, respectively. The effects of these three compounds on cell proliferation, growth and viability of MCF7 cells, representing human breast adenocarcinoma as well as A427 (human lung carcinoma) and A431 (human epidermoid carcinoma) cells, were tested using EdU assay, IncuCyte® live-cell imaging and MTT assay. The most active compound in inhibiting MCF7 cell proliferation was acetoxystachybotrydial acetate with an EC50 value of 0.39 µM. In addition, acetoxystachybotrydial acetate turned out to inhibit the growth of all three cell lines completely at a concentration of 1 µM. In contrast, cell viability was impaired only moderately, to 37%, 14% and 23% in MCF7, A427 and A431 cells, respectively. 相似文献
166.
Ralf Bienert Franziska Emmerling Andreas F. Thünemann 《Analytical and bioanalytical chemistry》2009,395(6):1651-1660
The spherical gold nanoparticle reference materials RM 8011, RM 8012, and RM 8013, with a nominal radius of 5, 15, and 30 nm,
respectively, have been available since 2008 from NIST. These materials are recommended as standards for nanoparticle size
measurements and for the study of the biological effects of nanoparticles, e.g., in pre-clinical biomedical research. We report
on determination of the size distributions of these gold nanoparticles using different small-angle X-ray scattering (SAXS)
instruments. Measurements with a classical Kratky type SAXS instrument are compared with a synchrotron SAXS technique. Samples
were investigated in situ, positioned in capillaries and in levitated droplets. The number-weighted size distributions were
determined applying model scattering functions based on (a) Gaussian, (b) log-normal, and (c) Schulz distributions. The mean
radii are 4.36 ± 0.04 nm (RM 8011), 12.20 ± 0.03 nm (RM 8012), and 25.74 ± 0.27 nm (RM 8013). Low polydispersities, defined
as relative width of the distributions, were detected with values of 0.067 ± 0.006 (RM 8011), 0.103 ± 0.003, (RM 8012), and
0.10 ± 0.01 (RM 8013). The results are in agreement with integral values determined from classical evaluation procedures,
such as the radius of gyration (Guinier) and particle volume (Kratky). No indications of particle aggregation and particle
interactions—repulsive or attractive—were found. We recommend SAXS as a standard method for a fast and precise determination
of size distributions of nanoparticles.
相似文献
167.
Tanja Schaffran Franziska Lissel Göran Karlsson Katarina Edwards Regine Peschka-Süss Detlef Gabel 《Journal of organometallic chemistry》2009,694(11):1708-1380
We have prepared two new boron-containing lipids with potential use in boron neutron capture therapy of tumors. These lipids consist of a diethanolamine frame with two myristoyl chains bonded as esters, and a butylene or ethyleneoxyethylene unit linking the doubly negatively charged dodecaborate cluster to the amino function of the frame, obtained by nucleophilic attack of the amino on the tetrahydrofurane and dioxane derivatives, respectively, of closo-dodecaborate. The latter cluster lipid can form liposomes at 25 °C whereas the former lipid at this temperature assembles into bilayer disks. Both lipids form stable liposomes when mixed with suitable helper lipids. The thermotropic behavior was found to be different for the two lipids, with the butylene lipid showing sharp melting transitions at surprisingly high temperatures. Toxicity in vitro and in vivo varies greatly, with the butylene derivative being more toxic than the ethyleneoxyethylene derivative. 相似文献
168.
Franziska Hunger Meor F. Zulkifli Benjamin A. O. Williams Frank Beyrau Christian Hasse 《Flow, Turbulence and Combustion》2016,97(1):231-262
In the present study laminar and turbulent oxy-fuel jet flames are investigated both experimentally and numerically with emphasis on the direct comparison of the Rayleigh signal. The Rayleigh signal was measured for both flame setups, correcting for background light appropriately. Two downstream regions were recorded for the laminar flame and three for the turbulent flame. Equivalently, the signal was processed numerically based on the numerical species data and temperature. The laminar flame was used for validating the procedure of processing the Rayleigh signal. Both the numerical species data and the temperature are known from detailed simulations, so a predicted Rayleigh signal can easily be obtained. Further, the influence of the choice of the kinetic mechanism, radiation and diffusion model was investigated. In contrast, in the turbulent Large Eddy Simulation, the Rayleigh signal has to be computed using an appropriate turbulence-chemistry interaction model in order to obtain the Reynolds-filtered Rayleigh signal which is of non-linear nature. In the present investigation, the Rayleigh signal was incorporated in the flamelet/progress variable approach. The statistics of the experimental and numerical Rayleigh signal were then compared. The proposed procedure of directly comparing the experimental and predicted Rayleigh signal was shown to be advantageous in model validation especially in turbulent flame configurations. The procedure enables accurate model validation across an entire 2D field of view whilst using a realistic fuel-oxidizer combination and reducing experimental complexity. 相似文献
169.
Phil Liebing Franziska Stein Liane Hilfert Volker Lorenz Karyna Oliynyk Frank T. Edelmann 《无机化学与普通化学杂志》2019,645(1):36-43
Nine new organoammonium violurates [R1R2R3NH][C4H2N3O4] [R1 = R2 = H, R3 = c‐C3H5 ( 2 ), R3 = tBu ( 3 ), R3 = adamantyl ( 4 ), R3 = C6H2Me2‐4,5‐NH2‐2 ( 5 ); R1 = H, R2 = R3 = Et ( 6 ), iPr ( 7 ); R1 = H, R2/R3 = (–CH2–)4 ( 8 ); R1 = R2 = R3 = Et ( 9 ); R1 = R2 = Me, R3 = (CH2)2NMe2 ( 10 )] were prepared by treatment of violuric acid ( 1 ) with a variety of primary, secondary, and tertiary amines. With the exception of orange 5 , all these violurate salts form bright blue or blue‐purple crystalline solids. The acidic triethylammonium violurate [NHEt3]H[C4H2N3O4]2 · H2O ( 9a ) was isolated in the form of red‐violet, plate‐like crystals by the reaction of violuric acid hydrate with triethylamine in a molar ratio of 2:1 in ethanol. All compounds were fully characterized by their IR and NMR (1H, 13C) data as well as elemental analyses. X‐ray crystal structures determinations of 2 , 7 , and 9a revealed supramolecular self‐assembly through networks of N–H ··· N and N–H ··· O hydrogen bonds in the crystalline state. 相似文献
170.
Annika Honold Clara Lettl Franziska Schindele Boris Illarionov Rainer Haas Matthias Witschel Adelbert Bacher Markus Fischer 《Helvetica chimica acta》2019,102(3)
A library of over 103 thousand compounds was screened for inhibitors of the IspD domain (2‐C‐methyl‐d ‐erythritol 4‐phosphate cytidylyl transferase domain) of the bifunctional IspDF protein from Helicobacter pylori using a photometric assay. Around 300 compounds showed IC50 values below 100 μm , and three compounds had IC50 values below 1 μm . A few IspD inhibitors could also inhibit the IspF domain (2‐C‐Methyl‐d ‐erythritol‐2,4‐cyclopyrophosphate synthase) of the IspDF protein. The most potent IspD inhibitors were tested as growth inhibitors of H. pylori. Several compounds showed inhibition of bacterial growth with IC50 in the single‐digit μm range. The most potent growth inhibitor had an IC50 value of 3.4 μm . The most potent growth inhibitor without measurable effect on eukaryotic cell viability had an IC50 value of 7.2 μm . 相似文献