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991.
Nina Hammer Karina Mathisen Tina Zscherpe De Chen Magnus R?nning 《Topics in Catalysis》2011,54(13-15):922-930
The impact of thermal treatment at various preparation stages of carbon supported Au/TiO2 catalysts prior to oxidation of CO in the presence and absence of hydrogen was studied. An increase in catalytic activity for thermally treated samples due to a more ordered structure of TiO2 was observed. A reversible deactivation of the catalysts occurred in the absence of hydrogen. However, the activity was restored at preferential CO oxidation conditions in presence of hydrogen. 相似文献
992.
993.
Jaafar M Serrano-Ramón L Iglesias-Freire O Fernández-Pacheco A Ibarra MR De Teresa JM Asenjo A 《Nanoscale research letters》2011,6(1):407
High-resolution magnetic imaging is of utmost importance to understand magnetism at the nanoscale. In the present work, we use a magnetic force microscope (MFM) operating under in-plane magnetic field in order to observe with high accuracy the domain configuration changes in Co nanowires as a function of the externally applied magnetic field. The main result is the quantitative evaluation of the coercive field of the individual nanostructures. Such characterization is performed by using an MFM-based technique in which a map of the magnetic signal is obtained as a function of both the lateral displacement and the magnetic field. 相似文献
994.
Maga G Falchi F Radi M Botta L Casaluce G Bernardini M Irannejad H Manetti F Garbelli A Samuele A Zanoli S Esté JA Gonzalez E Zucca E Paolucci S Baldanti F De Rijck J Debyser Z Botta M 《ChemMedChem》2011,6(8):1371-1389
A hit optimization protocol applied to the first nonnucleoside inhibitor of the ATPase activity of human DEAD-box RNA helicase DDX3 led to the design and synthesis of second-generation rhodanine derivatives with better inhibitory activity toward cellular DDX3 and HIV-1 replication. Additional DDX3 inhibitors were identified among triazine compounds. Biological data were rationalized in terms of structure-activity relationships and docking simulations. Antiviral activity and cytotoxicity of selected DDX3 inhibitors are reported and discussed. A thorough analysis confirmed human DDX3 as a valid anti-HIV target. The compounds described herein represent a significant advance in the pursuit of novel drugs that target HIV-1 host cofactors. 相似文献
995.
996.
Luis Alcides Brandini De Boni Isaac Newton Lima da Silva 《Fuel Processing Technology》2011,92(5):1001-1006
The production of biodiesel is rapidly expanding around the world, making it more important to produce this fuel with more energy efficiency. In this paper, we observed a series of transesterification reactions of soy bean oil and methyl alcohol catalyzed by potassium hydroxide. The observations were made using a non-invasive optical technique. This technique is useful to indicate the endpoint of a transesterification reaction or to determine when this reaction is reaching the state of chemical equilibrium. This study made it possible to improve the follow-up of the transesterification reaction, by optimizing the reaction time with a better monitoring system. 相似文献
997.
Vandormael B De Wachter R Martins JC Hendrickx PM Keresztes A Ballet S Mallareddy JR Tóth F Tóth G Tourwé D 《ChemMedChem》2011,6(11):2035-2047
Dermorphin analogues, containing a (S)‐ and (R)‐4‐amino‐1,2,4,5‐tetrahydro‐2‐benzazepin‐3‐one scaffold (Aba) and the α‐methylated analogues as conformationally constrained phenylalanines, were prepared. Asymmetric phase‐transfer catalysis was unable to provide the (S)‐α‐Me‐o‐cyanophenylalanine precursor for (S)‐α‐MeAba in acceptable enantiomeric purity. However, by using a Schöllkopf chiral auxiliary, this intermediate was obtained in 88 % ee. [(S)‐Aba 3‐Gly 4]dermorphin retained μ‐opioid affinity but displayed an increased δ‐affinity. The corresponding R epimer was considerably less potent. In contrast, the [(R)‐α‐MeAba 3‐Gly 4]dermorphin isomer was more potent than its S epimer. Tar‐MD simulations of both non‐methylated [Aba 3‐Gly 4]dermorphin analogues showed a degree of folding at the C‐terminal residues toward the N terminus of the peptide, without however, adopting a stabilized β‐turn conformation. The α‐methylated analogues, on the other hand, exhibited a type I/I′ β‐turn conformation over the α‐MeAba 3 and Gly 4 residues, which was stabilized by a hydrogen bond involving Tyr 5‐HN and D ‐Ala 2‐CO. 相似文献
998.
In this article, the important role of the intrinsic defects in size-controlled ZnO nanowires (NWs) which play a critical role in the properties of the NWs, was studied with a combined innovative experimental analysis. The NWs prepared by both the aqueous solution method and chemical vapour deposition process were of increasing length and decreasing size-to-volume (S/V) ratio. The combined approach involved different analytical and spectroscopic techniques and from the correlation between the different measurements, the concentration of the oxygen vacancies jointly with the zinc interstitials defects and the zinc vacancy defects was observed to be positively or negatively correlated, respectively, with the magnitude of the photoluminescence intensity and radiative lifetimes. Furthermore, the experimental results also suggest that the oxygen vacancy defects are not only spatially located on the surface of the NW but an increasing fraction of the total oxygen vacancy defects connected with the green emission is also located in an annulus region beneath the surface as the ZnO NWs elongate. On the other hand, as the donor concentration plays a critical function in the properties of the ZnO NWs, an analytical model was derived for the calculation of the donor concentration of the NWs directly from its reverse-biased current-voltage characteristics obtained from the conductive atomic force microscopy measurements. 相似文献
999.
Cerdobbel A De Winter K Aerts D Kuipers R Joosten HJ Soetaert W Desmet T 《Protein engineering, design & selection : PEDS》2011,24(11):829-834
Sucrose phosphorylase is a promising biocatalyst for the glycosylation of a wide variety of acceptor molecules, but its low thermostability is a serious drawback for industrial applications. In this work, the stability of the enzyme from Bifidobacterium adolescentis has been significantly improved by a combination of smart and rational mutagenesis. The former consists of substituting the most flexible residues with amino acids that occur more frequently at the corresponding positions in related sequences, while the latter is based on a careful inspection of the enzyme's crystal structure to promote electrostatic interactions. In this way, a variant enzyme could be created that contains six mutations and whose half-life at the industrially relevant temperature of 60 °C has more than doubled compared with the wild-type enzyme. An increased stability in the presence of organic co-solvents could also be observed, although these effects were most noticeable at low temperatures. 相似文献
1000.
De Vico L Iversen L Sørensen MH Brandbyge M Nygård J Martinez KL Jensen JH 《Nanoscale》2011,3(9):3635-3640
A single charge screening model of surface charge sensors in liquids (De Vico et al., Nanoscale, 2011, 3, 706-717) is extended to multiple charges to model the effect of the charge distributions of analyte proteins on FET sensor response. With this model we show that counter-intuitive signal changes (e.g. a positive signal change due to a net positive protein binding to a p-type conductor) can occur for certain combinations of charge distributions and Debye lengths. The new method is applied to interpret published experimental data on Streptavidin (Ishikawa et al., ACS Nano, 2009, 3, 3969-3976) and Nucleocapsid protein (Ishikawa et al., ACS Nano, 2009, 3, 1219-1224). 相似文献