全文获取类型
收费全文 | 212篇 |
免费 | 9篇 |
国内免费 | 10篇 |
专业分类
电工技术 | 3篇 |
化学工业 | 41篇 |
金属工艺 | 2篇 |
机械仪表 | 1篇 |
建筑科学 | 12篇 |
能源动力 | 13篇 |
轻工业 | 33篇 |
水利工程 | 1篇 |
石油天然气 | 5篇 |
无线电 | 31篇 |
一般工业技术 | 32篇 |
冶金工业 | 26篇 |
原子能技术 | 1篇 |
自动化技术 | 30篇 |
出版年
2023年 | 5篇 |
2022年 | 3篇 |
2021年 | 12篇 |
2020年 | 11篇 |
2019年 | 4篇 |
2018年 | 12篇 |
2017年 | 8篇 |
2016年 | 5篇 |
2015年 | 9篇 |
2014年 | 7篇 |
2013年 | 17篇 |
2012年 | 20篇 |
2011年 | 17篇 |
2010年 | 9篇 |
2009年 | 6篇 |
2008年 | 5篇 |
2007年 | 13篇 |
2006年 | 5篇 |
2005年 | 2篇 |
2004年 | 3篇 |
2003年 | 4篇 |
2002年 | 3篇 |
2001年 | 4篇 |
2000年 | 1篇 |
1998年 | 4篇 |
1997年 | 6篇 |
1996年 | 4篇 |
1995年 | 6篇 |
1994年 | 3篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1986年 | 2篇 |
1983年 | 1篇 |
1982年 | 3篇 |
1981年 | 2篇 |
1980年 | 5篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1974年 | 1篇 |
1969年 | 1篇 |
1966年 | 1篇 |
排序方式: 共有231条查询结果,搜索用时 15 毫秒
1.
2.
E. I. Basaldella J.C. Tara G. Aguilar Armenta M. E. Patiño Iglesias 《Journal of Porous Materials》2007,14(3):273-278
Samples of mesoporous silica SBA-15 were prepared under hydrothermal conditions where Cu cations were incorporated to the
structure by impregnation in order to compare the adsorption behavior in the presence and absence of this element. The adsorption/desorption
equilibrium isotherms of propylene, propane, and N2 were measured to evaluate their usefulness in the propane/propylene separation.
All the adsorption isotherms of SBA-15 measured in the absence of Cu cations were described by the Freundlich equation, while
the adsorption isotherms of propane on Cu/SBA-15 were better represented by the Henry equation and those of propylene were
satisfactorily described by the Langmuir model in the range P < 100 Torr. The adsorption uptake of propylene increased and that of propane decreased in Cu/SBA-15 as compared to the amounts
observed in the SBA-15 sample. The presence of Cu atoms in the adsorbent lattice increased the selectivity towards propylene.
Under some working conditions the adsorbed amount of propylene in Cu/SBA-15 sample was totally reversible and the propane
uptake, negligible. 相似文献
3.
The feasibility of chromium(VI) to induce graft polymerization of methyl methacrylate onto silk was investigated. The rate of grafting was determined by varying monomer concentration, chromium(VI) concentration, temperature, acidity of the medium, nature of the silk, reaction medium, and redox system. The graft yield increased with increasing monomer concentration up to 0.65M, and with further increase of monomer the graft yield decreased. The graft yield increased with increasing chromium(VI) concentration. The grafting is considerably influenced by chemical modification of silk prior to grafting. The graft yield is influenced by thiourea concentration, decreasing with increasing thiourea concentration. The effect of certain inorganic salts and anionic surfactants on the rate of grafting was investigated. 相似文献
4.
This work processes linear prediction (LP) residual in the time domain at three different levels, extracts speaker information,
and demonstrates their significance and also different nature for text-independent speaker recognition. The subsegmental analysis
considers LP residual in blocks of 5 msec with shift of 2.5 msec to extract speaker information. The segmental analysis extracts
speaker information by processing in blocks of 20 msec with shift of 2.5 msec. The suprasegmental speaker information is extracted
by viewing in blocks of 250 msec with shift of 6.25 msec. The speaker identification and verification studies performed using
NIST-99 and NIST-03 databases demonstrate that the segmental analysis provides best performance followed by subsegmental analysis.
The suprasegmental analysis gives the least performance. However, the evidences from all the three levels of processing seem
to be different and combine well to provide improved performance, demonstrating different speaker information captured at
each level of processing. Finally, the combined evidence from all the three levels of processing together with vocal tract
information further improves the speaker recognition performance. 相似文献
5.
Biswajit Pati B. C. Sutar B. N. Parida Piyush R. Das R. N. P. Choudhury 《Journal of Materials Science: Materials in Electronics》2013,24(5):1608-1616
Barium orthovanadate (Ba3V2O8), a derivative of perovskite family has been prepared using a mixed-oxide technique. The room temperature X-ray diffraction analysis has confirmed the formation of a single phase compound in trigonal crystal structure. The study of microstructure by scanning electron microscopy shows that the compound has well defined grains, distributed uniformly throughout the surface. The studies of dielectric parameters (εr and tan δ) of the compound as a function of temperature at three different frequencies (100, 500, 1,000 kHz) exhibit that they are almost temperature independent at low and medium temperature ranges. Detailed studies of impedance and related parameters exhibit that the electrical properties of the material are strongly dependent on temperature, and bear a good correlation with its microstructures. The bulk resistance, evaluated from complex impedance spectra, is found to be decreasing with rise in temperature. It shows that the material has negative temperature co-efficient of resistance similar to that of semiconductors. The same behaviour has also been observed in the study of I–V characteristics of the material. The complex electric modulus analysis indicates the possibility of hopping conduction mechanism in the system with non-exponential type of conductivity relaxation. The nature of variation of dc conductivity with temperature confirms the Arrhenius behavior of the material. The ac conductivity spectra show a typical signature of an ionic conducting system, and are found to obey Jonscher’s universal power law. 相似文献
6.
Jnyana Ranjan Pati Subhajit Dutta Philippe Eliaers Pinakeswar Mahanta Pradip Kumar Chatterjee 《Drying Technology》2016,34(9):1073-1084
The intensification of interfacial mass, heat, and momentum transfer makes vortex chambers potentially interesting for the efficient drying of paddy, allowing shorter drying times and/or more compact equipment. The presence of a shell introduces particular challenges. Intraparticle diffusion limitations are strong and may reduce the advantage from intensified interfacial mass and heat transfer and the efficiency of air usage. Furthermore, high shear and normal stresses in the fast rotating particle bed may cause damage to the paddy shell, posing problems for transport and storage. With these specific aspects in mind, the use of vortex chambers for paddy drying is experimentally evaluated. 相似文献
7.
Shiva Bejugama Shibu Chameettachal Falguni Pati Ajoy Kumar Pandey 《Ceramics International》2021,47(2):1594-1601
Niobia (1 mol. %) doped Ceria Stabilized Zirconia (NbCSZ) powders were synthesized using a co-precipitation method. The synthesized powders were uniaxially compacted and sintered in air. The two-step sintering method was adopted to sinter the samples, and the sintering schedule was optimized based on density, grain size, the phase present, and the hardness of the sintered sample. It was observed that the two-step sintering method effectively suppressed the grain growth of NbCSZ samples and helped in achieving a finer grain size of 1.57 μm along with the hardness of 1195 HV10 and optimum fracture toughness value 6.20 MPa m1/2. The Low-Temperature Degradation (LTD) behavior of the sintered samples was estimated through an accelerated hydrothermal aging test, which revealed that the samples are highly resistant to LTD and shown no phase change even after 150 h of study. Moreover, the cytocompatibility of the NbCSZ was tested by culturing MG63 cells on the samples for 7 days. The NbCSZ was found to be highly biocompatible as evident from cell viability and metabolic activity assay. 相似文献
8.
9.
10.
Sardiñas N Vázquez C Gil-Serna J González-Jaén MT Patiño B 《International journal of food microbiology》2011,145(1):121-125
Aflatoxins are important mycotoxins that represent a serious risk for human and animal health. These mycotoxins are mainly produced by Aspergillus flavus and Aspergillus parasiticus, two closely related species with different array of aflatoxins. In this work, two specific quantitative PCR (qPCR) assays were developed to detect and quantify both species in wheat flour using primers based on the multicopy ITS2 rDNA target sequence. The species specificity of the assays was tested in a wide range of strains of these species and others colonizing the same commodities. The sensitivity of the assay was estimated in 2.5 pg/reaction in both species. Discrimination capacity for detection and relative quantification of A. flavus and A. parasiticus DNA were analyzed using samples with DNA mixtures containing also other fungal species at different ratios. Both qPCR assays could detect spore concentrations equal or higher than 106 spores/g in flour samples without prior incubation. These assays are valuable tools to improve diagnosis at an early stage and in all critical control points of food chain integrated in HACCP strategies. 相似文献