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991.
Elisandra Rigo André E. Polloni Daniela Remonatto Francieli Arbter Silvana Menoncin J. Vladimir Oliveira Débora de Oliveira Helen Treichel Susana J. Kalil Jorge L. Ninow Marco Di Luccio 《Applied biochemistry and biotechnology》2010,162(7):1881-1888
The main objective of this work was the isolation and screening of microorganisms with potential for producing lipases for the synthesis of fatty esters as well as evaluating the specificity of the enzymes produced, using different alcohols (methanol, ethanol, n-propanol, and butanol) and fatty acids (oleic and lauric acids) as substrates. Promising biocatalysts for organic synthesis were obtained in this work. The isolated strains 69F and 161Y showed ability to efficiently catalyze the reaction for production of n-propyl oleate. Other strains can also be considered of potential interest, as 74F, 111Y, and 186Y. The future development of production using different substrates could result in cheap crude lipase of high importance to industrial applicability. 相似文献
992.
We report on the use of optical Faraday rotation to monitor the nuclear-spin signal in a set of model (19)F- and (1)H-rich fluids. Our approach integrates optical detection with high-field, pulsed NMR so as to record the time-resolved evolution of nuclear-spins after rf excitation. Comparison of chemical-shift-resolved resonances allows us to set order-of-magnitude constrains on the relative amplitudes of hyperfine coupling constants for different bonding geometries. When evaluated against coil induction, the present detection modality suffers from poorer sensitivity, but improvement could be attained via multipass schemes. Because illumination is off-resonant i.e., the medium is optically transparent, this methodology could find extensions in a broad class of fluids and soft condensed matter systems. 相似文献
993.
Coppola C Paciello A Mangiapia G Licen S Boccalon M De Napoli L Paduano L Tecilla P Montesarchio D 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(46):13757-13772
A novel fluorescently labelled synthetic ionophore, based on a cyclic phosphate-linked disaccharide (CyPLOS) backbone and decorated with four tetraethylene glycol tails carrying dansyl units, has been synthesised in 12 steps in 26% overall yield. The key intermediate in the synthetic strategy is a novel glucoside building block, serving through its 2- and 3-hydroxy groups as the anchor point for flexible tetraethylene glycol tentacles with reactive azido moieties at their ends. To test the versatility of this glucoside scaffold, it was preliminarily functionalised with a set of diverse probes--as fluorescent, redox-active or hydrophobic tags--either by reduction of the azides followed by condensation with activated carboxylic acid derivatives, or by a direct coupling with a terminal alkyne in a Cu(I)-promoted 1,3-dipolar cycloaddition. Tagging of the monomeric building block with dansyl residues allowed us to prepare a fluorescent, amphiphilic macrocycle, which was investigated for its propensity to self-aggregate in CDCl(3)--studied by means of concentration-dependent (31)P NMR spectroscopy experiments--and in aqueous solution, in which combined dynamic light scattering (DLS) and small-angle neutron scattering (SANS) measurements provided a detailed physico-chemical analysis of the self-assembled systems, mainly organised in the form of large vesicles. Its ion-transport properties through phospholipid bilayers, determined by HPTS fluorescence assays, showed this compound to be more active than the previously synthesised CyPLOS congeners. Solvent-dependent fluorescence changes for the labelled ionophore in liposome suspension established that the dansyl moieties are dispersed in environments with polarity intermediate between those of CH(2)Cl(2) and propan-2-ol, suggesting that the CyPLOS tentacles infiltrate the mid-polar region of the membranes. 相似文献
994.
Anna Laura Capriotti Giulio Caracciolo Giuseppe Caruso Chiara Cavaliere Daniela Pozzi Roberto Samperi Aldo Laganà 《Analytical and bioanalytical chemistry》2010,398(7-8):2895-2903
Plasma protein adsorption is regarded as a key factor in the in vivo organ distribution of intravenously administered drug carriers, and strongly depends on vector surface characteristics. The present study aimed to characterize the “protein corona” absorbed onto DC-Chol-DOPE cationic liposomes. This system was chosen because it is one of the most efficient and widely used non-viral formulations in vitro and a potential candidate for in vivo transfection of genetic material. After incubation of human plasma with cationic liposomes, nanoparticle–protein complex was separated from plasma by centrifugation. An integrated approach based on protein separation by one-dimensional 12% polyacrylamide gel electrophoresis followed by the automated HPLC-Chip technology coupled to a high-resolution mass spectrometer was employed for protein corona characterization. Thirty gel lanes, approximately 2 mm, were cut, digested and analyzed by HPLC-MS/MS. Fifty-eight human plasma proteins adsorbed onto DC-Chol-DOPE cationic liposomes were identified. The knowledge of the interactions of proteins with liposomes can be exploited for future controlled design of colloidal drug carriers and possibly in the controlled creation of biocompatible surfaces of other devices that come into contact with proteins in body fluids.
Scheme of protein adsorption onto nanoparticle surface 相似文献
995.
Wolf-Walther du Mont Roxana Bîrzoi Delia Bugnariu Constantin G. Daniliuc Christine Goers Rafael Guerrero Gimeno Thorsten Gust Daniela Lungu Antje Riecke Rainer Bartsch Laszlo Nyulászi Zoltan Benkõ Laszlo Könczöl 《Comptes Rendus Chimie》2010,13(8-9):1111-1126
An overview is given on synthesis and structures of new bidentate phosphaalkene ligands [(RMe2Si)2CP]2E (E = O, NR, N?) and (RMe2Si)2CPN(R′)PR′′2. Exceptional properties of these ligands, extending beyond predictable properties of phosphaalkenes are: (i) the NSi bond cleavage of [(iPrMe2Si)2CP]2NSiMe3 with AuI and RhI chloro complexes under mild conditions leading to binuclear complexes of the 6π-delocalised imidobisphosphaalkene anion [(iPrMe2Si)2CP]2N?, and (ii) the chlorotropic formation of molecular 1:2 PdII and PtII metallochloroylid complexes with novel ylid-type ligands [(RMe2Si)2CP(Cl)N(R)PR2]?, and the transformation of a P-platina-P-chloroylid complex into a C-platina phosphaalkene by intramolecular chlorosilane elimination. Properties of the heavier congeners [(RMe2Si)2CP]2E (E = S, Se, Te, PR, P?, As?) and (RMe2Si)2CPEPR′′2 (E = S, Se, Te) are also described. 相似文献
996.
Roland Becker Daniela Capatina Julie Joie 《Numerical Methods for Partial Differential Equations》2012,28(3):1013-1041
We study a discontinuous Galerkin finite element method (DGFEM) for the Stokes equations with a weak stabilization of the viscous term. We prove that, as the stabilization parameter γ tends to infinity, the solution converges at speed γ?1 to the solution of some stable and well‐known nonconforming finite element methods (NCFEM) for the Stokes equations. In addition, we show that an a posteriori error estimator for the DGFEM‐solution based on the reconstruction of a locally conservative H(div, Ω)‐tensor tends at the same speed to a classical a posteriori error estimator for the NCFEM‐solution. These results can be used to affirm the robustness of the DGFEM‐method and also underline the close relationship between the two approaches. © 2011 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2011 相似文献
997.
Iannazzo D Piperno A Ferlazzo A Pistone A Milone C Lanza M Cimino F Speciale A Trombetta D Saija A Galvagno S 《Organic & biomolecular chemistry》2012,10(5):1025-1031
We report the synthesis and the characterization of different multi-walled carbon nanotubes (MWCNTs) linked to natural molecules, 5,7-coumarins and/or oleic acid, obtained from purified pristine MWCNTs by a cascade of chemical functionalization. The activities of these modified MWCNTs were investigated in vitro on human umbilical vein endothelial cells (HUVECs) by evaluating their ability to influence cell viability and to induce cell apoptosis. Our data showed that pristine MWCNTs are markedly cytotoxic; conversely, the carboxylated carbon nanotubes, much more readily dispersed in aqueous solutions and CNT-Link, the key intermediate designed by us for the drug anchorage, are biocompatible at the tested concentrations (1 and 10 μg ml(-1)). 相似文献
998.
Comegna D DellaGreca M Rosaria Iesce M Previtera L Zarrelli A Zuppolini S 《Organic & biomolecular chemistry》2012,10(6):1219-1224
3- or 4-Aroylfurans have been prepared selectively and in high yields from a common precursor by simple tuning of reaction conditions in Friedel-Crafts acylation promoted by triflic anhydride. The formation of products can be explained on the basis of the ring-chain tautomerism occurring in compounds equipped with two neighbouring carboxylic functions. Since 4-aroylfuran derivatives show a typical lignan backbone, suitable hydrogenation conditions were found out to gain tetrahydrofuran lignans. 相似文献
999.
Siebert JM Baumann D Zeller A Mailänder V Landfester K 《Macromolecular bioscience》2012,12(2):165-175
5,6-Benzo-2-methylene-1,3-dioxepane (BMDO) is used to obtain degradable polymeric nanoparticles via a statistical free-radical copolymerization with MMA and styrene in direct miniemulsion. The nanoparticles are analyzed by means of IR, NMR, DLS, SEM, and TEM. They show excellent cellular uptake and drug delivery properties. The cellular uptake into HeLa cells of particles resulting from copolymerization of BMDO with styrene is drastically enhanced compared to pure polystyrene. As a model drug system, paclitaxel is incorporated in PBMDO particles and its release and the effect on HeLa cells is studied and compared to commercial drug formulations. It is found that a drug delivery system based on PBMDO shows an excellent pharmacological effect. 相似文献