全文获取类型
收费全文 | 511篇 |
免费 | 35篇 |
国内免费 | 5篇 |
专业分类
电工技术 | 10篇 |
综合类 | 1篇 |
化学工业 | 106篇 |
金属工艺 | 32篇 |
机械仪表 | 17篇 |
建筑科学 | 14篇 |
矿业工程 | 1篇 |
能源动力 | 8篇 |
轻工业 | 36篇 |
水利工程 | 2篇 |
石油天然气 | 8篇 |
无线电 | 77篇 |
一般工业技术 | 91篇 |
冶金工业 | 29篇 |
原子能技术 | 1篇 |
自动化技术 | 118篇 |
出版年
2024年 | 2篇 |
2023年 | 6篇 |
2022年 | 19篇 |
2021年 | 16篇 |
2020年 | 30篇 |
2019年 | 31篇 |
2018年 | 45篇 |
2017年 | 33篇 |
2016年 | 33篇 |
2015年 | 26篇 |
2014年 | 28篇 |
2013年 | 43篇 |
2012年 | 28篇 |
2011年 | 46篇 |
2010年 | 20篇 |
2009年 | 16篇 |
2008年 | 10篇 |
2007年 | 8篇 |
2006年 | 9篇 |
2005年 | 7篇 |
2004年 | 9篇 |
2003年 | 5篇 |
2002年 | 4篇 |
2001年 | 5篇 |
2000年 | 4篇 |
1999年 | 7篇 |
1998年 | 9篇 |
1997年 | 5篇 |
1996年 | 1篇 |
1995年 | 4篇 |
1994年 | 1篇 |
1993年 | 4篇 |
1992年 | 3篇 |
1990年 | 5篇 |
1989年 | 1篇 |
1988年 | 2篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 4篇 |
1984年 | 1篇 |
1983年 | 3篇 |
1982年 | 1篇 |
1980年 | 1篇 |
1979年 | 2篇 |
1977年 | 3篇 |
1974年 | 1篇 |
1973年 | 2篇 |
排序方式: 共有551条查询结果,搜索用时 20 毫秒
61.
V Baeyens V Kaltsatos B Boisramé E Varesio JL Veuthey M Fathi LP Balant M Gex-Fabry R Gurny 《Canadian Metallurgical Quarterly》1998,52(1-2):215-220
The aziridinium ion of ethylcholine (AF64A), a cholinergic neurotoxin, was injected into the right striatum of a rat. The unilateral injection of 10 nmol AF64A reduced the activity of choline acetyltransferase (CAT) and the tissue content of acetylcholine (ACh) in the striatum. The striatal contents of dopamine (DA), norepinephrine (NE), 5-hydroxyindoleacetic acid (5-HIAA) and gamma-aminobutyric acid (GABA) were unchanged. These results suggest that the cholinospecificity in the striatal lesion was induced by the 10 nmol dose of AF64A. The number of N-methyl-D-aspartic acid (NMDA) receptors in the striatum treated with 10 nmol AF64A was determined by a specific binding assay using [3H](+/-)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid ([3H]CPP), a selective ligand for NMDA receptors. The number of the NMDA receptors decreased significantly in the injected area. On the other hand, in a microdialysis using normal rats, the perfusion of 50 microM NMDA into the striatum increased ACh release. The perfusion of 100 microM MK801 which is the specific and non-competitive NMDA receptor antagonist, decreased the basal levels of ACh release and blocked NMDA-elicited ACh release. Taken together, the present results strongly suggest that a population of NMDA receptors exists on cholinergic interneurons within the striatum, and it directly regulates ACh release. 相似文献
62.
63.
A computer program has been developed for the simulation of gas-liquid absorption columns. The calculations are based on known assumptions and methods – the two-film theory. Mass and energy balances together with chemical reactions are carried out for each tray of the column. The results obtained from the simulation procedure are compared with those measured at industrial plants. For the items “rich solution temperature” and “calculated number of trays” the agreement of calculated and measured results are satisfactory. However, for the CO2 and H2S content of the streams only few comparisons could be made due to the fact that no measured values are available. 相似文献
64.
Fathi Moussa Pascale Chretie Pierre Dubois Laurence Chuniaud Michelle Dessante Fran ois Trivin Pierre-Yves Sizaret Viatcheslav Agafonov Ren C olin Henri Szwarc Virginie Greugny Claude Fabre Andr Rassat 《Fullerenes, Nanotubes and Carbon Nanostructures》1995,3(3):333-342
In order to check its possible acute toxicity, C60 was incorporated into living human phagocytes. It was observed that C60 has no influence on the survival of human leukocytes. 相似文献
65.
66.
Fathi Habashi Farouk T. Awadalla 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1986,36(1):1-6
When phosphate rock is dissolved in nitric acid, phosphoric acid and uranium can be selectively extracted by tertiary amyl alcohol; other impurities including the lanthanides remain in the aqueous phase. Uranium can be recovered from the alcohol phase by selective stripping and the lanthanides from the raffinate by extraction with tributyl phosphate. 相似文献
67.
Chalcopyrite reacts readily with SO3 at about 100°C to form water-soluble sulfates; the reaction is approximately: 3CuFeS2+26SO3→3CuSO4+FeSO4+Fe2(SO4)3+25SO2 The presence of about 4 pct O2 in the gas phase greatly accelerates the reaction presumably due to the complete transformation of ferrous into ferric sulfate in an extremely porous form: 2CuFeS2+17SO3+1/2O2→2CuSO4+Fe2(SO4)3+16SO2 A stoichiometric mixture of SO2+1/2O2 behaves towards chalcopyrite in nearly the same way as SO3 although only in the temperature range 350° to 700°C. 相似文献
68.
In the present work, we report the effects of C(60)-pretreatments on acute carbon tetrachloride intoxication in rats, a classical model for studying free-radical-mediated liver injury. Our results show that aqueous C(60) suspensions prepared without using any polar organic solvent not only have no acute or subacute toxicity in rodents but they also protect their livers in a dose-dependent manner against free-radical damage. To be sure, according to histopathological examinations and biological tests, pristine C(60) can be considered as a powerful liver-protective agent. 相似文献
69.
A new technique for analysing the time-domain response of carbon nanotube (CNT) interconnects, based on transmission line modelling, that takes the effects of both contact and fundamental (quantum) resistances into account is introduced. A new sixth-order linear parametric expression for the transfer function of these lines has been presented for the first time. For verification purposes, the step response of a driver-CNT bundle-load configuration for a 32 nm technology node, using the new technique and HSPICE simulation have been compared, with which the obtained results show an excellent match. Also the effect of contact resistance on the step response, especially the propagation delay, has been studied. The obtained results show that for the length of a CNT bundle equal to 50 mum with the diameter of each individual CNT 1 nm, the propagation delay changes from 0.138 to 5.58 ns for the contact resistance values from 1 to 50 k Omega, i.e. a variation range of 39.43 times the minimum value. The related delay variations for the length values 200 mum, 500 mum and 1000 mum, are 31.37, 22.61 and 15.42 times the minimum value, respectively. 相似文献
70.
Poly(o-aminophenol) (POAP) was formed by successive cyclic voltammetry in monomer solution in the presence of sodium dodecyl sulfate (SDS) on the surface of a carbon paste electrode. The electrochemical behavior of the SDS-POAP carbon paste electrode has been investigated by cyclic voltammetry in 0.5 M HClO4 and 5 mM K4[Fe(CN)6]/0.1 M KCl solutions as the supporting electrolyte and model system, respectively. Ni(II) ions were incorporated into the electrode by immersion of the polymeric modified electrode having amine groups in 0.1 M Ni(II) ion solution. Cyclic voltammetric and chronoamperometric experiments were used for the electrochemical study of this modified electrode. A good redox behavior of the Ni(III)/Ni(II) couple at the surface of electrode can be observed. The electrocatalytic oxidations of methanol and ethylene glycol (EG) at the surface of the Ni/SDS-POAP electrode were studied in a 0.1 M NaOH solution. Compared to bare carbon paste and POAP-modified carbon paste electrodes, the SDS-POAP electrode significantly enhanced the catalytic efficiency of Ni ions for methanol oxidation. Finally, using a chronoamperometric method, the catalytic rate constants (k) for methanol and ethylene glycol were found to be 2.04 × 105 and 1.05 × 107 cm3 mol−1 s−1, respectively. 相似文献