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931.
Cytotoxicity and fluorescence studies of silica-coated CdSe quantum dots for bioimaging applications
Muthunayagam Vibin Ramachandran Vinayakan Annie John Vijayamma Raji Chellappan S. Rejiya Naresh S. Vinesh Annie Abraham 《Journal of nanoparticle research》2011,13(6):2587-2596
The toxicological effects of silica-coated CdSe quantum dots (QDs) were investigated systematically on human cervical cancer
cell line. Trioctylphosphine oxide capped CdSe QDs were synthesized and rendered water soluble by overcoating with silica,
using aminopropyl silane as silica precursor. The cytotoxicity studies were conducted by exposing cells to freshly synthesized
QDs as a function of time (0–72 h) and concentration up to micromolar level by Lactate dehydrogenase assay, MTT [3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium
Bromide] assay, Neutral red cell viability assay, Trypan blue dye exclusion method and morphological examination of cells
using phase contrast microscope. The in vitro analysis results showed that the silica-coated CdSe QDs were nontoxic even at
higher loadings. Subsequently the in vivo fluorescence was also demonstrated by intravenous administration of the QDs in Swiss
albino mice. The fluorescence images in the cryosections of tissues depicted strong luminescence property of silica-coated
QDs under biological conditions. These results confirmed the role of these luminescent materials in biological labeling and
imaging applications. 相似文献
932.
Abraham Colin-Molina Marcus J. Jellen Dr. Joelis Rodríguez-Hernández Dr. Miguel Eduardo Cifuentes-Quintal Jorge Barroso Dr. Rubén A. Toscano Prof. Gabriel Merino Prof. Braulio Rodríguez-Molina 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(51):11727-11733
Two new crystalline rotors 1 and 2 assembled through N−H⋅⋅⋅N hydrogen bonds by using halogenated carbazole as stators and 1,4-diaza[2.2.2]bicyclooctane (DABCO) as the rotator, are described. The dynamic characterization through 1H T1 relaxometry experiments indicate very low rotational activation barriers (Ea) of 0.67 kcal mol−1 for 1 and 0.26 kcal mol−1 for 2 , indicating that DABCO can reach a THz frequency at room temperature in the latter. These Ea values are supported by solid-state density functional theory computations. Interestingly, both supramolecular rotors show a phase transition between 298 and 250 K, revealed by differential scanning calorimetry and single-crystal X-ray diffraction. The subtle changes in the crystalline environment of these rotors that can alter the motion of an almost barrierless DABCO are discussed here. 相似文献
933.
Anuji Abraham Omar Elkassabany Mary E. Krause Andrew Ott 《Magnetic resonance in chemistry : MRC》2019,57(10):873-877
Determining the moisture content in lyophilized solids is a fundamental step towards predicting the quality and stability of lyophilized products, but conventional methods are time-consuming, invasive, and destructive. High levels of residual moisture in a lyophilized product can lead to cake collapse, product degradation, and reduced shelf life. The aim of this study was to develop a fast, noninvasive, nondestructive, and inexpensive method for determining the moisture content in a lyophilized monoclonal antibody (mAb) formulation using benchtop low-field time-domain nuclear magnetic resonance spectroscopy. 相似文献
934.
T.G. Akin Sharon Kennedy Ben Dribus Jeremy L. Marzuola Lise Johnson Jason Alexander E.R.I. Abraham 《Optics Communications》2012,285(1):84-89
Multiply-connected traps for cold, neutral atoms fix vortex cores of quantum gases. Laguerre–Gaussian laser modes are ideal for such traps due to their phase stability. We report theoretical calculations of the Bose–Einstein condensation transition properties and thermal characteristics of neutral atoms trapped in multiply connected geometries formed by Laguerre–Gaussian (LGpl) beams. Specifically, we consider atoms confined to the anti-node of a LG01 laser mode detuned to the red of an atomic resonance frequency, and those confined in the node of a blue-detuned LG11 beam. We compare the results of using the full potential to those approximating the potential minimum with a simple harmonic oscillator potential. We find that deviations between calculations of the full potential and the simple harmonic oscillator can be up to 3%–8% for trap parameters consistent with typical experiments. 相似文献
935.
Nagaraja SreeHarsha Jagadeesh G. Hiremath Rajesh Kumar Aitha Abraham J. Domb Bandar E. Al‐Dhubiab Chandramouli Ramnarayanan Abdullah Mossa Alzahrani Katharigatta N. Venugopala Sabah H. Akrawi Mahesh Attimarad Anroop B. Nair 《先进技术聚合物》2019,30(10):2613-2622
This research presents a thin‐film hydration‐solvent evaporation method to formulate the paclitaxel loaded poly (DL lactic acid co castor oil) 4:6 with poloxamer‐F68 cylindrical shape nanoparticles. The particles were less than 250 nanometers (nm) in size, with an average width of 60 nm and an average length of 100 nm. The percent yield, encapsulation efficiency (EE), and percent drug loading (DL) were detected. This approach produces drug loading values between 5% and 20% w/w. X‐ray powder diffraction (XRD) identified the physicochemical properties of nanoparticles differential scanning calorimetry (DSC) and Fourier‐transform infrared spectroscopy (FTIR). The investigation shows that the drug is molecularly dispersed in polymers or given in an amorphous or semicrystalline state. Horizontal water bath shaker technology considered the in vitro release of PTX loaded nanoparticles under sink conditions. Poly (DL lactic acid co castor oil) 4:6 nanoparticles exhibited a sustained release analysis. At the end of 30 hours, the percent cumulative drug release from the formulations was between 74.52% and 92.87% for F1 and F4. In vitro cytotoxicity assays indicate that PTX having p (DLLA:CO60:40) nanoparticles have a higher cytotoxic effect on MCF‐7/ADR. 相似文献
936.
Raymond J. Abraham Lee Griffiths Manuel Perez 《Magnetic resonance in chemistry : MRC》2014,52(7):395-408
The 1H chemical shifts of 48 amides in DMSO solvent are assigned and presented. The solvent shifts Δδ (DMSO‐CDCl3) are large (1–2 ppm) for the NH protons but smaller and negative (?0.1 to ?0.2 ppm) for close range protons. A selection of the observed solvent shifts is compared with calculated shifts from the present model and from GIAO calculations. Those for the NH protons agree with both calculations, but other solvent shifts such as Δδ(CHO) are not well reproduced by the GIAO calculations. The 1H chemical shifts of the amides in DMSO were analysed using a functional approach for near ( ≤ 3 bonds removed) protons and the electric field, magnetic anisotropy and steric effect of the amide group for more distant protons. The chemical shifts of the NH protons of acetanilide and benzamide vary linearly with the π density on the αN and βC atoms, respectively. The C=O anisotropy and steric effect are in general little changed from the values in CDCl3. The effects of substituents F, Cl, Me on the NH proton shifts are reproduced. The electric field coefficient for the protons in DMSO is 90% of that in CDCl3. There is no steric effect of the C=O oxygen on the NH proton in an NH…O=C hydrogen bond. The observed deshielding is due to the electric field effect. The calculated chemical shifts agree well with the observed shifts (RMS error of 0.106 ppm for the data set of 257 entries). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
937.
Jesús Sánchez-Oro Anna Martínez-Gavara Manuel Laguna Rafael Martí Abraham Duarte 《Computational Optimization and Applications》2017,68(3):775-797
Automated graph-drawing systems utilize procedures to place vertices and arcs in order to produce graphs with desired properties. Incremental or dynamic procedures are those that preserve key characteristics when updating an existing drawing. These methods are particularly useful in areas such as planning and logistics, where updates are frequent. We propose a procedure based on the scatter search methodology that is adapted to the incremental drawing problem in hierarchical graphs. These drawings can be used to represent any acyclic graph. Comprehensive computational experiments are used to test the efficiency and effectiveness of the proposed procedure. 相似文献
938.
Martin Gillard Guillaume Piraux Martin Daenen Michaël Abraham Dr. Ludovic Troian-Gautier Dr. Laure Bar Hugues Bonnet Prof. Frédérique Loiseau Dr. Hélène Jamet Dr. Jérôme Dejeu Prof. Eric Defrancq Prof. Benjamin Elias 《Chemistry (Weinheim an der Bergstrasse, Germany)》2022,28(66):e202202251
Photosensitizers that gather high photo-oxidizing power and strong visible-light absorption are of great interest in the development of new photo-chemotherapeutics. Indeed, such compounds constitute attractive candidates for the design of type I photosensitizers that are not dependent on the presence of oxygen. In this paper, we report on the synthesis and studies of new ruthenium(II) complexes that display strong visible-light absorption and can oxidize guanine residues under visible-light irradiation, as evidenced by nanosecond transient absorption spectroscopy. The reported compounds also tightly bind to G-quadruplex DNA structures from the human telomeric sequence (TTAGGG repeat). The kinetic and thermodynamic parameters of the interaction of these Ru(II) complexes with G-quadruplex and duplex DNA were studied thanks to luminescence titrations and bio-layer interferometry measurements, which revealed higher affinities towards the non-canonical G-quadruplex architecture. Docking experiments and non-covalent ionic analysis allowed us to gain information on the mode and the strength of the interaction of the compounds towards G-quadruplex and duplex DNA. The different studies emphasize the substantial influence of the position and the number of non-chelating nitrogen atoms on the interaction with both types of DNA secondary structures. 相似文献
939.
940.
Brian D. Bowes Harun Koku Kirk J. Czymmek Abraham M. Lenhoff 《Journal of chromatography. A》2009,1216(45):7774-7784
Adsorption behavior is compared on a traditional agarose-based ion-exchange resin and on two dextran-modified resins, using three proteins to examine the effect of protein size. The latter resins typically exhibit higher static capacities at low ionic strengths and electron microscopy provides direct visual evidence supporting the view that the higher static capacities are due to the larger available binding volume afforded by the dextran. However, isocratic retention experiments reveal that the larger proteins can be almost completely excluded from the dextran layer at high ionic strengths, potentially leading to significant losses in static capacity at relevant column loading conditions. Knowledge of resin and protein properties is used to estimate physical limits on the static capacities of the resins in order to provide a meaningful interpretation of the observed static capacities. Results of such estimates are consistent with the expectation that available surface area is limiting for traditional resins. In dextran-modified media, however, the volume of the dextran layer appears to limit adsorption when the protein charge is low relative to the resin charge, but the protein–resin electroneutrality may be limiting when the protein charge is relatively high. Such analyses may prove useful for semiquantitative prediction of maximum static capacities and selection of operating conditions when combined with protein transport information. 相似文献