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71.
Tatiana S. de Araujo Zélia S. Macedo Petrus A. S. C. de Oliveira Mário E. G. Valerio 《Journal of Materials Science》2007,42(7):2236-2243
Pure and Cr3+-doped hydroxyapatite (HAP) were prepared via chemical precipitation route. The XRD measurements revealed that the typical
HAP powder pattern was obtained. SEM analysis indicated that aggregates of nanoparticles were formed. EDX analysis indicates
that the [Ca]/[P] concentration ratio was higher than the expected values but can be explained by the presence of carbonate
groups as dopants. The optical absorption spectra of the doped samples presented absorption bands typical of Cr3+ occupying to different crystalline sites. From the position of the bands, it was possible to estimate the crystal field parameters
for both sites of Cr3+ in the HAP matrix. The emission spectra of the Cr-doped samples were also investigated and typical transitions of the dopant
ion, in trivalent state, were identified. The potential use of the Cr3+-HAP as fluorescent probes for medical applications was discussed. 相似文献
72.
Chiara Renso Miriam Baglioni Jose António F. de Macedo Roberto Trasarti Monica Wachowicz 《Knowledge and Information Systems》2013,37(2):331-362
The widespread use of mobile devices is producing a huge amount of trajectory data, making the discovery of movement patterns possible, which are crucial for understanding human behavior. Significant advances have been made with regard to knowledge discovery, but the process now needs to be extended bearing in mind the emerging field of behavior informatics. This paper describes the formalization of a semantic-enriched KDD process for supporting meaningful pattern interpretations of human behavior. Our approach is based on the integration of inductive reasoning (movement pattern discovery) and deductive reasoning (human behavior inference). We describe the implemented Athena system, which supports such a process, along with the experimental results on two different application domains related to traffic and recreation management. 相似文献
73.
This paper presents a new model for the economic optimization of a process operation where two assignable causes may occur, one affecting the mean and the other the variance. The process may thus operate in statistical control, under the effect of either one of the assignable causes or under the effect of both assignable causes. The model employed uses the Bayes theorem to determine the probabilities of operating under the effect of each assignable cause. Based on these probabilities, and following an economic optimization criterion, decisions are made on the necessary actions (stop the process for investigation or not) as well as on the time of the next sampling instance and the size of the next sample. The superiority of the proposed model is estimated by comparing its economic outcome against the outcome of simpler approaches such as Fp (Fixed-parameter) and adaptive Vp (Variable-parameter) Shewhart charts for a number of cases. The numerical investigation indicates that the economic improvement of the new model may be significant. 相似文献
74.
Emerson de Araujo Macedo Alba Cristina Magalhaes Alves de Melo Gerson Henrique Pfitscher Azzedine Boukerche 《The Journal of supercomputing》2013,63(3):740-756
Multiple Sequence Alignment (MSA) is an important problem in Bioinformatics that aims to align more than two sequences in order to emphasize similarity regions. This problem is known to be NP-Hard, so heuristic methods are used to solve it. DIALIGN-TX is an iterative heuristic method for MSA that generates alignments by concatenating ungapped regions with high similarity. Usually, the first phase of MSA algorithms is parallelized by distributing several independent tasks among the nodes. Even though heterogeneous multicore clusters are becoming very common nowadays, very few task allocation policies were proposed for this type of architecture. This paper proposes an MPI/OpenMP master/slave parallel strategy to run DIALIGN-TX in heterogeneous multicore clusters, with several allocation policies. We show that an appropriate choice of the master node has great impact on the overall system performance. Also, the results obtained in a heterogeneous multicore cluster composed of 4 nodes (30 cores), with real sequence sets show that the execution time can be drastically reduced when the appropriate allocation policy is used. 相似文献
75.
Nadia Nedjah Luneque Silva Junior Luiza de Macedo Mourelle 《Expert systems with applications》2013,40(16):6661-6673
Networks-on-Chip (NoC) is an interesting option in design of communication infrastructures for embedded systems. It provides a scalable structure and balanced communication between the cores. Parallel applications that take advantage of the NoC architectures, are usually are communication-intensive. Thus, a big deal of data packets is transmitted simultaneously through the network. In order to avoid congestion delays that deteriorate the execution time of the implemented applications, an efficient routing strategy must be thought of carefully. In this paper, the ant colony optimization paradigm is explored to find and optimize routes in a mesh-based NoC. The proposed routing algorithms are simple yet efficient. The routing optimization is driven by the minimization of total latency during packets transmission between the tasks that compose the application. The presented performance evaluation is threefold: first, the impact of well-known synthetic traffic patterns is assessed; second, randomly generated applications are mapped into the NoC infrastructure and some synthetic communication traffics, that follow known patterns, are used to simulate real situations; third, sixteen real-world applications of the E3S and one specific application for digital image processing are mapped and their execution time evaluated. In both cases, the obtained results are compared to those obtained with known general purpose algorithms for deadlock free routing. The comparison avers the effectiveness and superiority of the ant colony inspired routing. 相似文献
76.
Nuno M. Garrido Ioannis G. Economou António J. Queimada Miguel Jorge Eugénia A. Macedo 《American Institute of Chemical Engineers》2012,58(6):1929-1938
In recent years molecular simulation has emerged as a useful tool to predict physical properties of complex chemical systems. A methodology to estimate the n‐hexane/water and 1‐octanol/water partition coefficients of environmentally relevant solutes, namely substituted alkyl‐aromatic molecules, chlorobenzenes, polychlorinated biphenyls (PCBs) and polychlorinated diphenyl ethers (PCDEs) using molecular simulation is elucidated here. The partition coefficients are calculated based on the absolute solvation Gibbs energies in each phase which are estimated from molecular dynamics simulations employing the thermodynamic integration approach. Very encouraging results, with average absolute deviations of 0.4 log P units are presented. Consequently, this molecular‐based approach with a strong physical background can provide reliable prediction of the partition coefficients in different solvent pairs without the a priori knowledge of experimental data. © 2011 American Institute of Chemical Engineers AIChE J, 58: 1929–1938, 2012 相似文献
77.
Oviedo MS Ramirez ML Barros GG Chulze SN 《International journal of food microbiology》2011,149(2):127-132
The aim of this study was to determine the effects of water activity (aw) (0.99-0.90), temperature (15, 25 and 30 °C) and their interactions on growth and alternariol (AOH) and alternariol monomethyl ether (AME) production by Alternaria alternata on irradiated soya beans. Maximum growth rates were obtained at 0.980 aw and 25 °C. Minimum aw level for growth was dependent on temperature. Both strains were able to grow at the lowest aw assayed (0.90). Maximum amount of AOH was produced at 0.98 aw but at different temperatures, 15 and 25 °C, for the strains RC 21 and RC 39 respectively. Maximum AME production was obtained at 0.98 aw and 30 °C for both strains. The concentration range of both toxins varied considerably depending on aw and temperature interactions. The two metabolites were produced over the temperature range 15 to 30 °C and aw range 0.99 to 0.96. The limiting aw for detectable mycotoxin production is slightly greater than that for growth. Two-dimensional profiles of aw × temperature were developed from these data to identify areas where conditions indicate a significant risk from AOH and AME accumulation on soya bean. Knowledge of AOH and AME production under marginal or sub-optimal temperature and aw conditions for growth can be important since improper storage conditions accompanied by elevated temperature and moisture content in the grain can favour further mycotoxin production and lead to reduction in grain quality. This could present a hazard if the grain is used for human consumption or animal feedstuff. 相似文献
78.
Marcelo Fernandes Cipreste Michele Rocha de Rezende Marlon Luiz Hneda Anderson Maia Peres Alexandre Alberto Chaves Cotta Verônica de Carvalho Teixeira Waldemar Augusto de Almeida Macedo Edésia Martins Barros de Sousa 《Ceramics International》2018,44(15):17800-17811
Hydroxyapatite (HA) nanoparticles (NPs) doped with different radioisotopes for use as theranostic systems play an important role in scientific research nowadays due to their ability to simultaneously act in the treatment and diagnosis of various types of cancers. In this work, we describe the synthesis and characterization of a hydroxyapatite/tenorite nanocomposite functionalized with folic acid, representing a nanotheranostic material with potential for application as an agent in positron emission tomography imaging systems and to act specifically in the treatment and diagnosis of osteosarcoma. 64Cu and 32P were produced by nuclear activation in the TRIGA reactor at CDTN. The obtained samples were characterized by XRD with Rietveld refinement, XAFS, SEM, BET, TGA, FTIR, CHN, ICP-AES, XPS and gamma spectroscopy. We investigated how CuO grows in HA NPs, the stability of the interactions between CuO and HA constituents and the interactions between folic acid and the surface of the HA NPs. The results indicate the formation of a second phase (tenorite) besides hydroxyapatite, and that the interactions between the two phases are stable, resulting in a nanocomposite. Furthermore, the activation of 64Cu and 32P inside the HA matrix, through the exposition to a neutron flux, produces a theranostic material of interest for biological tests. 相似文献
79.
Surendran Rajesh Daniel A. Macedo Rubens M. Nascimento Graziele L. Souza Filipe M.L. Figueiredo Fernando M.B. Marques 《International Journal of Hydrogen Energy》2013
Europium-doped ceria (EDC, Ce0.9Eu0.1O2−δ)/alkaline carbonate (LNC, (Li,Na)2CO3) composite ceramics prepared through a one-step citrate-based route were analyzed by powder X-ray diffraction, infrared and laser Raman spectroscopies as well as scanning and transmission electron microscopy. The electrochemical behavior of the electrolyte material was studied by impedance spectroscopy in air, CO2 and N2 + H2 (90/10 vol%, respectively) gas mixtures, in the temperature range 300–600 °C. The sub micrometric and even nanosized ceramic particles appeared as merged inside the mixed carbonates, with modest grain to grain necking. The EDC/LNC composite electrolytes showed a conductivity of 0.27 S cm−1 at 600 °C in air, amongst the best ever reported, exceeding the usual requirements for fuel cell applications. 相似文献
80.
Andrey V. Pyatigorets Joseph F. Labuz Sofia G. Mogilevskaya Henryk K. Stolarski 《Journal of Materials Science》2010,45(4):936-945
A new approach is proposed for the experimental study of the effective shear modulus of porous elastic materials using the uniaxial tension test. The idea is to measure strains at a few points surrounding a cluster of holes that represents the structure of the material. The representative cluster is placed in the material with the same elastic properties as those of the matrix. The measured strains lead to the properties of the equivalent circular inhomogeneity, which would produce the same elastic fields as from the cluster. An aluminum plate containing a cluster of seven circular or hexagonal holes was used. The effective shear modulus obtained from the strain data was compared with theoretical predictions and various bounds, and it was shown that the laboratory estimated values are quite accurate. The experimental technique can be used for the determination of the effective Poisson’s ratio of porous media and/or cellular solids if more detailed strain data are obtained. 相似文献