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881.
Laia Lidn Laura Lla-Hierro Mario Nuvolone Adriano Aguzzi Jesús vila Isidro Ferrer Jos Antonio del Río Rosalina Gavín 《International journal of molecular sciences》2021,22(10)
Tau protein is largely responsible for tauopathies, including Alzheimer’s disease (AD), where it accumulates in the brain as insoluble aggregates. Tau mRNA is regulated by alternative splicing, and inclusion or exclusion of exon 10 gives rise to the 3R and 4R isoforms respectively, whose balance is physiologically regulated. In this sense, one of the several factors that regulate alternative splicing of tau is GSK3β, whose activity is inhibited by the cellular prion protein (PrPC), which has different physiological functions in neuroprotection and neuronal differentiation. Moreover, a relationship between PrPC and tau expression levels has been reported during AD evolution. For this reason, in this study we aimed to analyze the role of PrPC and the implication of GSK3β in the regulation of tau exon 10 alternative splicing. We used AD human samples and mouse models of PrPC ablation and tau overexpression. In addition, we used primary neuronal cultures to develop functional studies. Our results revealed a paralleled association between PrPC expression and tau 4R isoforms in all models analyzed. In this sense, reduction or ablation of PrPC levels induces an increase in tau 3R/4R balance. More relevantly, our data points to GSK3β activity downstream from PrPC in this phenomenon. Our results indicate that PrPC plays a role in tau exon 10 inclusion through the inhibitory capacity of GSK3β. 相似文献
882.
Ignacio Guillen Antonio UrisHermelando Estelles Jaime LlinaresAna Llopis 《Building and Environment》2008
In this paper, laboratory measurements of sound reduction index for two types of cavity walls commonly used in façades are presented. The first type consists of “masonry–air cavity–brick” and the second one consists of “masonry–air cavity–-gypsum board”. Data are used to show that masonry walls with gypsum boards provide higher sound insulation than masonry cavity walls. The influence on sound reduction index of apertures made on external leaf of the wall to ventilate the cavity of the wall is also examined. 相似文献
883.
Effect of Particle Size on Monometallic and Bimetallic (Au,Pd)/C
on the Liquid Phase Oxidation of Glycerol 总被引:2,自引:0,他引:2
Nikolaos Dimitratos Jose Antonio Lopez-Sanchez David Lennon Francesca Porta Laura Prati Alberto Villa 《Catalysis Letters》2006,108(3-4):147-153
The influence of metal particle size of monometallic and bimetallic supported catalysts (Au, Pd, Au–Pd)/C was studied using
as a model reaction the liquid phase oxidation of glycerol. By tuning the metal particle size from 2 to 16 nm a progressive
decrease of activity and simultaneously an increase in the selectivity to sodium glycerate was observed. Moreover, the influence
of the temperature was studied and it was found that by increasing the temperature, only with a large particle size the formed
glycerate was retained and not over-oxidized to tartronate. 相似文献
884.
Jiwon Lee Bryan S. Der Christos S. Karamitros Wenzong Li Nicholas M. Marshall Oana I. Lungu Aleksandr E. Miklos Jianqing Xu Tae Hyun Kang Chang-Han Lee Bing Tan Randall A. Hughes Sang Taek Jung Gregory C. Ippolito Jeffrey J. Gray Yan Zhang Brian Kuhlman George Georgiou Andrew D. Ellington 《American Institute of Chemical Engineers》2020,66(3):e16864
We used the molecular modeling program Rosetta to identify clusters of amino acid substitutions in antibody fragments (scFvs and scAbs) that improve global protein stability and resistance to thermal deactivation. Using this methodology, we increased the melting temperature (Tm) and resistance to heat treatment of an antibody fragment that binds to the Clostridium botulinum hemagglutinin protein (anti-HA33). Two designed antibody fragment variants with two amino acid replacement clusters, designed to stabilize local regions, were shown to have both higher Tm compared to the parental scFv and importantly to retain full antigen binding activity after 2 hr of incubation at 70°C. The crystal structure of one thermostabilized scFv variants was solved at 1.6 Å and shown to be in close agreement with the RosettaAntibody model prediction. 相似文献
885.
Maria E. Amato Antonio Grassi Kenny B. Lipkowitz Giuseppe M. Lombardo Giuseppe C. Pappalardo Claudia Sadun 《Journal of Inorganic and Organometallic Polymers and Materials》1996,6(3):237-253
Suitable parameter sets for the CHARMm force field were derived for the structural units in polychlorophosphazene [P=N, P N, P Cl] using the Dinur Hagler energy second derivative procedure based on quantum mechanical SCI calculations using the 6–31G* basis set. To validate the reliability of the parameter set, structural results obtained with CHARMm for the adopted model compounds (OP2NCl5 and OP3N2Cl5) were compared with those derived fromab initio quantum mechanics using the 6–31G* basis set. Application of molecular dynamics (MD) simulations in combinatioin with the available X-ray diffraction data provided structural and conformational information on the polymer. The calculation made using the periodic boundary conditions (PBC) agree well with the polychlorophosphazene ordered in a monoclinic unit cell (a=5.98,b=12.99,c=4.92 A; β=111.7). This model was stabilized mainly by the image atoms contribution to the electrostatic energy term and had aquasi-planar conformation of the backbone chain (glide symmetry). The MD calculations also provided evidence that the difference between single and double PN bonds is less marked than that measured experimentally. This result is, however, in agreement with more recent and accurate X-ray studies on poly(methylphosphazene). Validation of the polymer model provided a complete picture, otherwise experimentally inaccessible, of the internal fluctuations of the polymeric chains. 相似文献
886.
Alberto Bencini Vittorio Duchi Antonio Casatello Nikolaos Kolios Michalis Fytikas Luca Sbaragli 《Geothermics》2004,33(5):141
Sixty-five water samples and seven associated gas samples have been collected on Lesbos island. The lithology and structural setting have resulted in two main types of hydrological circulation: a shallow circulation hosting low-salinity cold waters and a deeper one, hosting high-salinity hot waters that often emerge in thermal springs near the coast. The cold waters are characterized by Ca(Mg)-HCO3(SO4) composition, while the thermal waters generally have an Na-Cl composition. The chemical features of the former can be explained by their circulation in the ophiolite-bearing phyllitic basement and volcanic rocks. Waters circulating in the ultramafic layers of the basement are richer in Mg than the waters whose circulation is mainly within marble levels or volcanic rocks. The Na-Cl thermal waters are characterized by salinities ranging from 1910 to 35,700 mg/kg. As indicated by previous hydrogeochemical and isotopic studies, the Na-Cl composition of the thermal waters on Lesbos is the result of mixing between shallow meteoric waters and marine waters. While interacting with the minerals of the geothermal reservoir, the saline waters retain the Na/Cl sea water ratio but become enriched in Ca2+ and depleted in Mg2+ with respect to sea water.Processes of hydrothermal alteration at depth are activated by a gas phase enriched in CO2, which reaches the geothermal reservoir by rising along the deep fractures of the basement. Thermodynamic calculations based on hydrothermal alteration processes occurring at the estimated temperatures of the geothermal reservoir (about 120 °C) indicate that the thermal waters of Lesbos are in equilibrium with talc and dolomite. 相似文献
887.
Iñigo Navarro Antonio J. López-Martín Carlos A. de la Cruz Alfonso Carlosena 《Analog Integrated Circuits and Signal Processing》2004,41(2-3):159-166
A compact, four-quadrant analog CMOS multiplier featuring wide dynamic range is presented. The capacitive voltage division obtained by the use of Floating-Gate MOS (FGMOS) transistors, and an accurate wide-swing current mirror based on active bootstrapping, allow a wide input range, low harmonic distortion, and high linearity. Simulation and measurement results for a 0.8 μm CMOS prototype demonstrate the validity of the proposed approach. 相似文献
888.
Míguez-Framil M Moreda-Piñeiro A Bermejo-Barrera P López P Tabernero MJ Bermejo AM 《Analytical chemistry》2007,79(22):8564-8570
The use of ultrasound energy for accelerating the pronase E enzymatic hydrolysis of human hair for extracting illicit drugs has been novelty tested. The enzymatic extracts obtained after 30 min of sonication in an ultrasonic water bath were subjected to an optimized solid-phase extraction process, which involved a solution of 2.0% (v/v) acetic acid in methanol as eluting solution and concentration by N2 stream evaporation. A gas chromatography/mass spectrometry method was used to separate and determine cocaine, benzoylecgonine, codeine, morphine, and 6-monoacethylmorphine in 20 min. Variables affecting ultrasound-assisted pronase E hydrolysis such as hydrolysis temperature, hydrolysis time, enzyme concentration, catalyzer (1,4-dithiothreitol) concentration, ionic strength, pH, and ultrasound frequency were simultaneously evaluated by a Plackett-Burman design 2(8) PBD of resolution III. The most statistically significant variables were ionic strength and pH, which means that analyte extraction is mainly attributed to pronase E activity. The optimization or evaluation of all the factors has led to an accelerated pronase E hydrolysis of human hair, which can be completed in 30 min. Results have been found to be statistically similar to those obtained with conventional pronase E hydrolysis. The accelerated method was finally applied to several human hair samples from multidrug abusers. 相似文献
889.
Antonio M. Locci Roberto Orrù Giacomo Cao Zuhair A. Munir 《Journal of the American Ceramic Society》2006,89(3):848-855
The simultaneous synthesis and densification of dense TiC–TiB2 composite has been investigated starting from Ti, B4 C, and C as reactants, and using the spark plasma sintering (SPS) technique. The optimal conditions for complete conversion of the reactants to the composite were determined for different applied DC current levels. A kinetic investigation performed allows us to conclude that solid-state diffusion is the mechanism governing the synthesis process. It is seen that TiC is the first phase formed, while TiB2 formation occurs afterward. Two intermediate boride phases, i.e. TiB and Ti3 B4 , are also formed but, as the SPS holding time was augmented, they were gradually and completely converted to TiB2 . Moreover, it is found that in order to reach relatively high dense products, an electric current needs to be applied for time intervals longer than those required for obtaining complete conversion. A pure dense product (relative density ∼98%) was obtained when an electric pulsed current of 1100 A and a mechanical pressure of 20 MPa were applied for about 4 min. 相似文献
890.
V ctor X. Mendoza-Escamilla Alejandro Alonzo-Garc a Helvio R. Mollinedo Israel Gonz lez-Neria J. Antonio Y ez-Varela Sergio A. Martinez-Delgadillo 《中国化学工程学报》2018,26(5):942-956
In turbulence modeling, the RNG and Realizable models have important improvements in the turbulent production and dissipation terms in comparison to the Standard. The selection of the appropriate turbulence model has an impact on the convergence and solution in STRs, and they are used in mixing, multiphase modeling or as starting solution of transient models as DES and LES. Although there are several studies with the pitched blade turbine(PBT) impeller, most of them used the Standard model as representative of all k–ε models, using structured hexahedral grids composed of low number of cells, and in some cases under axial symmetry assumptions.Accordingly, in this work the assessment of the Standard, RNG and Realizable models to describe the turbulent flow field of this impeller, using the Multiple Reference Frame(MRF) and Sliding Mesh(SM) approaches with tetrahedral domains in dense grids, is presented. This kind of cell elements is especially suitable to reproduce complex geometries. Flow velocities and turbulent parameters were verified experimentally by PIV and torque measurements. The three models were capable of predicting fairly the pumping number, the power number based on torque, and velocities. Although the RNG improved the predictions of the turbulent kinetic energy and dissipation rate, the Realizable model presented better performance for both approaches. All models failed in the prediction of the total dissipation rate, and a dependence of its value on the number of cells for the MRF was found. 相似文献