全文获取类型
收费全文 | 138篇 |
免费 | 12篇 |
专业分类
化学工业 | 24篇 |
金属工艺 | 15篇 |
机械仪表 | 3篇 |
建筑科学 | 8篇 |
能源动力 | 9篇 |
轻工业 | 35篇 |
水利工程 | 3篇 |
石油天然气 | 1篇 |
无线电 | 17篇 |
一般工业技术 | 25篇 |
自动化技术 | 10篇 |
出版年
2024年 | 1篇 |
2023年 | 2篇 |
2022年 | 1篇 |
2021年 | 2篇 |
2020年 | 9篇 |
2019年 | 6篇 |
2018年 | 16篇 |
2017年 | 3篇 |
2016年 | 7篇 |
2015年 | 10篇 |
2014年 | 9篇 |
2013年 | 19篇 |
2012年 | 5篇 |
2011年 | 16篇 |
2010年 | 5篇 |
2009年 | 14篇 |
2008年 | 3篇 |
2007年 | 6篇 |
2006年 | 1篇 |
2005年 | 1篇 |
2004年 | 1篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1997年 | 1篇 |
1987年 | 1篇 |
1978年 | 1篇 |
1976年 | 1篇 |
排序方式: 共有150条查询结果,搜索用时 7 毫秒
71.
72.
Tadas Rimavičius Adas Gelžinis Antanas Verikas Evaldas Vaičiukynas Marija Bačauskienė Aleksėj Šaškov 《Signal, Image and Video Processing》2018,12(6):1107-1114
The main objective of this work is to establish an automated classification system of seabed images. A novel two-stage approach to solving the image region classification task is presented. The first stage is based on information characterizing geometry, colour and texture of the region being analysed. Random forests and support vector machines are considered as classifiers in this work. In the second stage, additional information characterizing image regions surrounding the region being analysed is used. The reliability of decisions made in the first stage regarding the surrounding regions is taken into account when constructing a feature vector for the second stage. The proposed technique was tested in an image region recognition task including five benthic classes: red algae, sponge, sand, lithothamnium and kelp. The task was solved with the average accuracy of 90.11% using a data set consisting of 4589 image regions and the tenfold cross-validation to assess the performance. The two-stage approach allowed increasing the classification accuracy for all the five classes, more than 27% for the “difficult” to recognize “kelp” class. 相似文献
73.
V. G. Mokerov I. S. Vasil’evskii G. B. Galiev J. Požela K. Požela A. Sužiedėlis V. Jucienė Č. Paškević 《Semiconductors》2009,43(4):458-462
It is experimentally found that the maximum drift velocity of electrons in quantum wells of differently arranged AlGaAs/GaAs heterostructures and pseudoamorphous Al0.36Ga0.64As/In0.15Ga0.85 As heterostructures is higher than the maximum drift velocity of electrons in bulk materials. It is established that no negative differential conductivity is exhibited by the field dependence of the drift velocity of two-dimensional electrons in GaAs and In0.15Ga0.85As. The drift velocity in the GaAs quantum well is saturated in fields several times higher than the field corresponding to the Γ-L intervalley transitions of electrons in bulk GaAs. 相似文献
74.
A. Zabielaitė A. Balčiūnaitė I. Stalnionienė S. Lichušina D. Šimkūnaitė J. Vaičiūnienė B. Šimkūnaitė-Stanynienė A. Selskis L. Tamašauskaitė-Tamašiūnaitė E. Norkus 《International Journal of Hydrogen Energy》2018,43(52):23310-23318
This work presents the study of catalytic activity of the fiber-shaped Co decorated with low amounts of Au or Pt nanoparticles for the hydrolysis of sodium borohydride in alkaline conditions. The morphology, structure and composition of the prepared catalysts were examined using Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Analysis and Inductively Coupled Plasma Optical Emission Spectroscopy.It was found that the decoration of the fiber-shaped Co with the Au or Pt nanoparticles allows enhancing of catalytic activity for the hydrolysis of sodium borohydride, compared with that of the pure fiber-shaped Co. 相似文献
75.
76.
P. Serapinas P.R. Venskutonis V. Aninkevičius Ž. Ežerinskis A. Galdikas V. Juzikienė 《Food chemistry》2008
The possibility to classify the provenance of a wide variety of randomly selected wines according to multi-element analysis data was tested. Large number of parameters is used for solution of such complex problem and the role of the noise increases. Stepwise approach is tested dividing the wine origin classification into some steps to simplify the problem. Outcomes of the approach are studied on the basis of the chemical analytical data obtained for 23 elements in 103 wines from seven countries. Anova was used to select the most informative elements at each step. Three or four elements often were found sufficient to discriminate between countries at 0.9 probability level. Principal component analysis was applied for concise data presentation. The possibility of application of the multivariate normal distribution to the principal components was tested and confirmed, and thoroughly used for the classification power estimates. Problems of indication of batches and adequate representation of those by samples are emphasized. 相似文献
77.
E. Norkus A. Vaškelis A. Jagminienė L. Tamašauskaitė-Tamašiūnaitė 《Journal of Applied Electrochemistry》2001,31(9):1061-1066
The kinetics of electroless silver deposition from solutions containing Co(II)-ammonia complex compounds as reducing agents was studied at 20 and 50 °C. The process rate depends on the solution pH and the concentration of Ag(I), Co(II) and ammonia species. Under optimum operating conditions selected a silver deposition rate up to 1.2 m h–1 can be obtained at 20 °C with high solution stability. At elevated temperature (50 °C) the rate increases and reaches 3 m h–1. The silver coatings obtained are of high quality, compact and bright. 相似文献
78.
Electroless copper deposition using Co(II)-ethylenediamine (En) complexes as reducing agents was investigated in 0.4–1.2 M En solutions at 50 and 70 °C. There is a complicated dependence of the process rate on pH, En concentration and temperature. A copper deposition rate up to 6 m h–1 (50–70 °C) in relatively stable solutions (pH 6) can be achieved. The stoichiometry of the Cu(II) reduction at pH 6–7 corresponds to the reaction:
The correlation between the rate of the copper deposition on the catalytic surface and the concentration of the
complex species in the solution was found. 相似文献
79.
The effect of irradiation with α particles on the current and optical responses of graded-gap AlxGa1?xAs/GaAs detectors of α particles and X-ray photons is studied. It is established that a reduction in both the current and optical response is caused by an increase in the rate of nonradiative recombination as the dose of α-particle radiation increases. 相似文献
80.
A heterostructure consisting of a graded-gap p-AlxGa1?xAs layer on an n-GaAs substrate is studied in relation to its role as a photoelectric-response detector of X-ray photons and α particles. It is found that the current-power sensitivity of the detector is as high as 0.13 A/W and the voltage-power sensitivity exceeds 106 V/W. The effect of preliminary irradiation with 5.48-MeV α particles (241Am) on the detector’s sensitivity is studied. It is established that the detector’s sensitivity is reduced by a factor of 1.5–2 after irradiation with α particles at a dose of 5 × 109 cm?2. A further increase in the radiation dose to 4 × 1010 cm?2 does not affect the detector’s sensitivity. 相似文献