全文获取类型
收费全文 | 98篇 |
免费 | 7篇 |
专业分类
化学工业 | 24篇 |
机械仪表 | 14篇 |
轻工业 | 2篇 |
无线电 | 16篇 |
一般工业技术 | 33篇 |
冶金工业 | 13篇 |
原子能技术 | 1篇 |
自动化技术 | 2篇 |
出版年
2020年 | 3篇 |
2019年 | 2篇 |
2018年 | 2篇 |
2017年 | 4篇 |
2016年 | 1篇 |
2013年 | 3篇 |
2012年 | 4篇 |
2011年 | 4篇 |
2009年 | 2篇 |
2008年 | 3篇 |
2007年 | 1篇 |
2006年 | 2篇 |
2005年 | 2篇 |
2004年 | 4篇 |
2003年 | 4篇 |
2002年 | 2篇 |
2001年 | 1篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 4篇 |
1996年 | 3篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 3篇 |
1991年 | 1篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1986年 | 2篇 |
1985年 | 2篇 |
1984年 | 2篇 |
1983年 | 2篇 |
1982年 | 1篇 |
1979年 | 2篇 |
1978年 | 3篇 |
1977年 | 1篇 |
1976年 | 5篇 |
1974年 | 1篇 |
1972年 | 1篇 |
1969年 | 6篇 |
1968年 | 2篇 |
排序方式: 共有105条查询结果,搜索用时 15 毫秒
1.
Penetrating injuries of the eye are an important cause of unilateral visual loss. We studied a series of 82 cases of penetrating injuries treated here from 1987 through 1993. The injuries were caused by sharp objects in 66% and blunt trauma in 6%. The prognosis after a penetrating injury is greatly influenced by the nature of the injury and the extent of the initial drainage. Among factors associated with an unfavorable visual outcome were diminished preoperative visual acuity and scleral wounds with dense vitreous hemorrhage. 相似文献
2.
Hot-carrier aging of the MOS transistor in the presence of spin-onglass as the interlevel dielectric
The effect of introducing a polysilicate or polysiloxane spin-on glass (SOG) as a component of the interlevel dielectric in a multilevel integrated circuit on the hot-carrier aging of the MOS transistor is discussed. It was found that the presence of SOG led to accelerated aging of the MOS transistor: factors of 20 and 5 for silicate and siloxane, respectively. This effect is attributed to water absorbed in the SOG films. a correlation was found for the hot-carrier aging rate and the amount of absorbed water 相似文献
3.
Alexander Glozman Efrat Lifshitz Kathrin Hoppe Ahdrey L. Rogach Horst Weller Alexander Echymüller 《Israel journal of chemistry》2001,41(1):39-44
The optical properties of thiol-stabilized CdTe nanocrystals have been examined. The thiol groups -SR generate a CdS shell at the interface, leading to a CdTe/CdS core—shell structure. The present paper describes our efforts to identify the influence of the CdTe–SR interface on the optical properties of the nanocrystals, utilizing photoluminescence and optically detected magnetic resonance (ODMR) spectroscopy. The photoluminescence spectrum consists of an excitonic peak, overlapped by a broad band at lower energies. The ODMR spectrum, in the spectral regime of the broad band, showed two resonance signals. They are associated with a trapped hole at an anisotropic site of a cadmium vacancy at the Cd–SR interface and an electron in the conduction band. 相似文献
4.
Micellar Growth in Cetylpyridinium Chloride/Alcohol System: Role of Long Chain Alcohol,Electrolyte and Surfactant Head Group
下载免费PDF全文
![点击此处可从《Journal of surfactants and detergents》网站下载免费的PDF全文](/ch/ext_images/free.gif)
Jasila Karayil Sanjeev Kumar Yeshayahu Talmon P. A. Hassan B. V. R. Tata Lisa Sreejith 《Journal of surfactants and detergents》2016,19(4):849-860
The microstructural transition of aqueous 0.1 M cetylpyridinium chloride (CPC) in the combined presence of salt KBr and long chain alcohol (C9OH-C12OH) has been studied as a function of alcohol concentration, electrolyte concentration and temperature. The viscosity of the CPC/KBr micellar system showed a peaked behavior with alcohol concentration (C 0), due to alcohol induced structural transition, which was confirmed by dynamic light scattering (DLS) and rheological analysis. Besides C 0, the chain length of alcohol (n) was found to show a remarkable effect on the micellization behavior of CPC/KBr system. It was observed that the ability of alcohol to induce micelle growth diminishes with n, which was well supported by viscosity, rheology and DLS measurements. To examine the effect of the electrolyte on the micellar growth, the salt concentration was varied from 0.05 to 0.15 M and it was observed that with increase in [KBr], the peak position shifts towards lower C 0. The effect of temperature on the micellar system showed interesting phase behavior for CPC/KBr/Decanol. The system exhibited a closed solubility loop with an upper critical solution temperature (UCST) > the lower critical solution temperature (LCST), reminiscence of nicotine-water system. The role of surfactant head group on the structural evolution was revealed by comparing the present results with our previous report for similar micellar system, CTAB/KBr/long chain alcohol. 相似文献
5.
Data processing in the split Hopkinson pressure bar tests 总被引:10,自引:0,他引:10
The effect on dynamic stress—strain curves of dispersion and shifting of elastic strain pulses travelling in a split Hopkinson pressure bar is reported. The dispersion correction is done in the frequency domain after employing FFT algorithm by adjusting the phase of each Fourier component. The three pulses (incident, reflected and transmitted) are analyzed inside three identical windows that propagate along the time axis with a reference velocity . The oscillations in the dynamic stress—strain curves are shown to be very sensitive to small variations in the value of co. A calibration procedure for determining the value of co for each SHPB setup is suggested. The predictions are compared to experimental measurements. 相似文献
6.
Rodríguez PN Zeni SN Suárez CE Ferreira Monteiro AG Martín de Portela ML Friedman SM Lifshitz F 《Archivos latinoamericanos de nutrición》2002,52(4):348-354
The purpose of this study was to investigate the impact of low fat diets in children aged 2 to 5. Eighty two children (40 females and 42 males) attending a school cafeteria (Province of Buenos Aires, Argentina), in a cross sectional study, were evaluated. Body weight (W), height (H) and body composition (BC) by bioimpedance were recorded. The anthropometric raw data were processed as Z-score of the weight-for-age (WEZ) and of the height-for-age (HAZ). Serum insulin-like growth factor 1 (IGF-1) and Zinc/haemoglobin ratio (Zn/Hb) were also measured. Results showed that 73.2% of the children were adequate (A) according WEZ, 13.4% were lean (L) and 13.4% overweight (O). 8.5% presented simultaneously impairment in WEZ and HAZ. Body fat percentage and energy metabolism were higher in O than in L and A (p < 0.05). Serum IGF-1's children--aged 4 to 5 years--with HAZ deficit were low than adequate HAZ ones. No statistical differences in Zn/Hb ratio between A, L and O were found. This cross sectional study suggests metabolic disorders in young children attending school cafeterias. These conclusions will allow to design balanced diets in order to optimize the resources, promote optimal growth and development and prevent adult diseases through dietary practices in childhood. 相似文献
7.
8.
Yeshayahu Talmon Janet L. Burns Matthew H. Chestnut David P. Siegel 《Microscopy research and technique》1990,14(1):6-12
We describe a new technique, time-resolved cryotransmission electron microscopy (TRC-TEM), that can be used to study changes in microstructure occurring during dynamic processes such as phase transitions and chemical reactions. The sample is prepared on an electron microscope grid maintained at a fixed temperature in a controlled atmosphere. The dynamic process is induced on the grid by a change in pH, salt, or reactant concentration by rapid mixing with appropriate solutions. Alternatively, induction is by rapid change of specimen temperature, or by controlled evaporation of a volatile component. We call such procedures on-the-grid processing. The dynamic process is permitted to run for a defined time and then the thin-film specimen is thermally fixed by plunging into liquid ethane at its freezing point, producing a cryotransmission electron microscopy specimen. By repeating this procedure with varying delays between induction and sample fixation, we can observe transient microstructures. We demonstrate the use of TRC-TEM to study the intermediate structures that form during the transitions between Lα, III, and HII liquid crystalline phases in phospholipid systems. We also identify several other possible applications of the technique. 相似文献
9.
10.
New experiments are described in which the gas phase hydrogen/deuterium (H/D) exchange kinetics is studied for multiply-protonated cytochrome c ions with +10 to +17 charges. The experimental technique involves electrospray ionization (ESI) combined with a fast-flow method. Experimental results are presented including (1) average rate constants for H/D exchange, (2) overall decay kinetics of the reactant ion, and (3) sets of profiles for consecutive deuterium exchanges as a function of the flow rate of ND3 as the deuterating agent. The maximum number of exchanged hydrogen atoms and the exchange rate are observed to increase with increasing charge. The +13 state demonstrates special reactivity with a reactant ion decay constant of 2.5 × 10−9 cc/molecule's. Further insight into the H/D exchange mechanism is anticipated upon analysis of the data with a newly developed algorithm for extracting site-specific rate constants from profiles for H/D exchange in gas phase protonated amino acids, their clusters, and peptides. The algorithm minimizes the mutual entropy or the Kullback-Leibler information divergence between the observed concentrations and a chosen model. 相似文献