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排序方式: 共有2286条查询结果,搜索用时 406 毫秒
31.
María Fernndez Alicia de Coo Ins Quintela Eliane García Mrcio Diniz-Freitas Jacobo Limeres Pedro Diz Juan Blanco ngel Carracedo Raquel Cruz 《International journal of molecular sciences》2021,22(12)
Severe periodontitis is prevalent in Down syndrome (DS). This study aimed to identify genetic variations associated with periodontitis in individuals with DS. The study group was distributed into DS patients with periodontitis (n = 50) and DS patients with healthy periodontium (n = 36). All samples were genotyped with the “Axiom Spanish Biobank” array, which contains 757,836 markers. An association analysis at the individual marker level using logistic regression, as well as at the gene level applying the sequence kernel association test (SKAT) was performed. The most significant genes were included in a pathway analysis using the free DAVID software. C12orf74 (rs4315121, p = 9.85 × 10−5, OR = 8.84), LOC101930064 (rs4814890, p = 9.61 × 10−5, OR = 0.13), KBTBD12 (rs1549874, p = 8.27 × 10−5, OR = 0.08), PIWIL1 (rs11060842, p = 7.82 × 10−5, OR = 9.05) and C16orf82 (rs62030877, p = 8.92 × 10−5, OR = 0.14) showed a higher probability in the individual analysis. The analysis at the gene level highlighted PIWIL, MIR9-2, LHCGR, TPR and BCR. At the signaling pathway level, PI3K-Akt, long-term depression and FoxO achieved nominal significance (p = 1.3 × 10−2, p = 5.1 × 10−3, p = 1.2 × 10−2, respectively). In summary, various metabolic pathways are involved in the pathogenesis of periodontitis in DS, including PI3K-Akt, which regulates cell proliferation and inflammatory response. 相似文献
32.
M. Baity-Jesi R.A. Baños A. Cruz L.A. Fernandez J.M. Gil-Narvion A. Gordillo-Guerrero D. Iñiguez A. Maiorano F. Mantovani E. Marinari V. Martin-Mayor J. Monforte-Garcia A. Muñoz Sudupe D. Navarro G. Parisi S. Perez-Gaviro M. Pivanti F. Ricci-Tersenghi J.J. Ruiz-Lorenzo S.F. Schifano B. Seoane A. Tarancon R. Tripiccione D. Yllanes 《Computer Physics Communications》2014
This paper describes the architecture, the development and the implementation of Janus II, a new generation application-driven number cruncher optimized for Monte Carlo simulations of spin systems (mainly spin glasses). This domain of computational physics is a recognized grand challenge of high-performance computing: the resources necessary to study in detail theoretical models that can make contact with experimental data are by far beyond those available using commodity computer systems. On the other hand, several specific features of the associated algorithms suggest that unconventional computer architectures–that can be implemented with available electronics technologies–may lead to order of magnitude increases in performance, reducing to acceptable values on human scales the time needed to carry out simulation campaigns that would take centuries on commercially available machines. Janus II is one such machine, recently developed and commissioned, that builds upon and improves on the successful JANUS machine, which has been used for physics since 2008 and is still in operation today. This paper describes in detail the motivations behind the project, the computational requirements, the architecture and the implementation of this new machine and compares its expected performances with those of currently available commercial systems. 相似文献
33.
Eduardo H.M. Cruz Matthias Diener Marco A.Z. Alves Philippe O.A. Navaux 《Journal of Parallel and Distributed Computing》2014
In current computer architectures, the communication performance between threads varies depending on the memory hierarchy. This performance difference must be considered when mapping parallel applications to processor cores. In parallel applications based on the shared memory paradigm, the communication is difficult to detect because it is implicit. Furthermore, dynamic mapping introduces several challenges, since it needs to find a suitable mapping and migrate the threads with a low overhead during the execution of the application. We propose a mechanism to detect the communication pattern of shared memory applications by monitoring cache coherence protocols. We also propose heuristics that, combined with our communication detection mechanism, allow the mapping to be performed dynamically by the operating system. Experiments with the NAS Parallel Benchmarks showed a reduction of up to 13.9% of the execution time, 30.5% of the cache misses and 39.4% of the number of invalidation messages. 相似文献
34.
Short fibers and fine particles of β-SiC were obtained by pyrolysis of Colombian rice husk (RH). The synthesis of SiC was carried out in a gas furnace: a mathematical model was developed in order to design and build this equipment and the process was optimized using an experimental design that included variables such as temperature, pyrolysis time, type of catalyst, and process atmosphere. The obtained material was characterized by using FTIR, DRX and SEM for microstructural characterization and EDS technique for chemical analysis. 相似文献
35.
Maritza F. Díaz Gómez Goitybell Martínez Téllez Maikel Arteaga Cruz Rafael Garcés Mancheno 《Journal of the American Oil Chemists' Society》2006,83(11):943-946
Ozonized theobroma fat is used as raw material in the manufacture of pessaries and cosmetic creams. Ozonization of theobroma
fat with water was carried out at different applied ozone dosages, and the resultant PV, acid value, iodine value, total hydroperoxide
content, and FA content were determined. PV and total hydroperoxide content showed a notable increase with applied ozone dosage
up to 35.7 mg/g. Acid value varied slightly from 4.1 to 9.9 mg KOH/g, and the iodine value fell to zero. PV and total hydroperoxide
content increased slightly with a higher applied ozone dosage. The comparison of total hydroperoxide measurement using ferrous
oxidation in xylenol orange assay and traditional iodometric assay for PV determination showed a significant linear correlation.
Small amounts of oleic acid were found in ozonized theobroma fat samples with iodine value equaling zero, which demonstrated
that iodine value determination is an inexact assay. During ozonization of theobroma fat, an increase in acid value of 18.9-fold
with respect to the initial value was observed owing to decomposition of peroxide. 相似文献
36.
Gustavo Avolio Dominique M. M.‐P. Schreurs Antonio Raffo Giovanni Crupi Alina Caddemi Giorgio Vannini B. Nauwelaers 《国际射频与微波计算机辅助工程杂志》2014,24(1):109-116
This work presents a straightforward approach aimed at modeling the dynamic I–V characteristics of microwave active solid‐state devices. The drain‐source current generator represents the most significant source of nonlinearity in a transistor and, therefore, its correct modeling is fundamental to predict accurately the current and voltage waveforms under large‐signal operation. The proposed approach relies on using a small set of low‐frequency time‐domain waveform measurements combined with numerical optimization‐based estimation of the nonlinear model parameters. The procedure is applied to a gallium nitride HEMT and silicon FinFET. The effectiveness of the modeling procedure in terms of prediction accuracy and generalization capability is demonstrated by validation of the extracted models under operating conditions different than the ones used for the parameters estimation. Good agreement between measurements and model simulations is achieved for both technologies and in both low‐ and high‐frequency range. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:109–116, 2014. 相似文献
37.
We analyze the complexity of equilibria problems for a class of strategic zero-sum games, called angel-daemon games. Those games were introduced to asses the performance of the execution of a web orchestration on a moderate faulty or under stress environment. Angel-daemon games are a natural example of zero-sum games whose representation is naturally succinct. We show that the problems of deciding the existence of a pure Nash equilibrium or of a dominant strategy for a given player are ${\Sigma}^{p}_{2}$ -complete. Furthermore, computing the value of an angel-daemon game is EXP-complete. Thus, our results match the already known classification of the corresponding problems for the generic families of succinctly represented games with exponential number of actions. 相似文献
38.
Erika Carneiro Riqueza Alcino Palermo de Aguiar Luiz Claudio Santa Maria Mônica Regina Marques Palermo de Aguiar 《Polymer Bulletin》2002,48(4-5):407-414
Summary
The preparation of a chelating ion-exchange network based on acrylonitrile was carried out by chemical modification with hydroxylamine.
The beads of resin were synthesized by aqueous suspension copolymerization of acrylonitrile (AN), styrene (STY) and divinylbenzene
(DVB). The influence of diluent used in the suspension polymerization on the structure of the resulting copolymers was evaluated.
The diluents employed were heptane (HEP), toluene (TOL) and anisole (ANI). It was found that the AN incorporation into copolymer
structure was dependent on the diluent used. Conversion of nitrile groups into the amidoxime was conducted by treatment with
hydroxylamine under alkaline solution. The resins were characterized by apparent density, surface area, average pore diameter,
elemental analysis (CHN), FTIR and optical microscopy. Based on the results obtained, it was possible to control the porosity
by diluent employed in the synthesis and to modify chemically a resin containing nitrile groups by hydroxylamine reaction.
Received: 6 October 2001/Revised version: 2 April 2002/ Accepted: 11 April 2002 相似文献
39.
Polycarbonate blends with the linear aliphatic polyesters poly(ethylene succinate) (PES), poly(ethylene adipate) (PEA), poly(1,4-butylene adipate) (PBA), and poly(hexamethylene sebacate) (PHS) were prepared by solution casting. Blends containing PES, PEA, and PBA exhibited a single Tg by DSC and thus form a single, miscible amorphous phase with polycarbonate. However, blends containing PHS exhibited only partial miscibility. Crystallinity of the polyesters was reduced by mixing with polycarbonate; however, plasticization by the polyesters induced crystallization of the polycarbonate. Miscibility in these systems is the result of an exothermic heat of mixing stemming from an interaction of the carbonyl dipole of the ester group with the aromatic carbonate. The effect of polyester structure on miscibility with polycarbonate is interpreted by and correlated with heats of mixing obtained by direct calorimetry of low molecular weight liquid analogs of the polymers. 相似文献
40.
Luis Carlos Ferreira Jr.Marcos A.S. Costa Pedro Ivo C. GuimarãesLuiz Claudio de Santa Maria 《Polymer》2002,43(14):3857-3862
Styrene polymerization was carried out with Ni(acac)2/MAO and Ni(acac)2/SiO2/MAO. The influence of reaction parameters (Al/Ni mole ratio, catalyst concentration, temperature and time polymerization) on styrene polymerization was evaluated. It was observed that both catalytic systems were affected by reaction parameters and that the heterogeneous catalyst presented higher activity than the homogeneous one. Polystyrenes with different molecular weight, stereoregularity and polydispersity were obtained. These results suggest that different active catalyst species could have been present. In addition, two types of methylaluminoxane (MAO) with different molecular weights were also evaluated as cocatalyst. As a result, the catalyst activity and stereospecificity were strongly affected by the MAO type. 相似文献