全文获取类型
收费全文 | 342篇 |
免费 | 2篇 |
专业分类
电工技术 | 6篇 |
化学工业 | 30篇 |
机械仪表 | 13篇 |
建筑科学 | 14篇 |
矿业工程 | 2篇 |
能源动力 | 11篇 |
轻工业 | 17篇 |
石油天然气 | 3篇 |
无线电 | 41篇 |
一般工业技术 | 41篇 |
冶金工业 | 132篇 |
原子能技术 | 2篇 |
自动化技术 | 32篇 |
出版年
2022年 | 2篇 |
2019年 | 4篇 |
2017年 | 4篇 |
2014年 | 3篇 |
2013年 | 23篇 |
2012年 | 4篇 |
2011年 | 7篇 |
2010年 | 11篇 |
2009年 | 3篇 |
2008年 | 12篇 |
2007年 | 7篇 |
2006年 | 8篇 |
2005年 | 6篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 8篇 |
2000年 | 2篇 |
1999年 | 8篇 |
1998年 | 45篇 |
1997年 | 18篇 |
1996年 | 15篇 |
1995年 | 18篇 |
1994年 | 13篇 |
1993年 | 9篇 |
1992年 | 5篇 |
1991年 | 6篇 |
1990年 | 3篇 |
1989年 | 2篇 |
1988年 | 3篇 |
1987年 | 3篇 |
1986年 | 5篇 |
1985年 | 5篇 |
1984年 | 4篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 3篇 |
1980年 | 3篇 |
1979年 | 5篇 |
1978年 | 2篇 |
1976年 | 12篇 |
1975年 | 4篇 |
1974年 | 3篇 |
1973年 | 3篇 |
1972年 | 4篇 |
1971年 | 4篇 |
1969年 | 3篇 |
1965年 | 3篇 |
1964年 | 2篇 |
1954年 | 1篇 |
排序方式: 共有344条查询结果,搜索用时 15 毫秒
51.
The nucleotide sequences of the conjugative F plasmid transfer region genes, traV and traR, have been determined. The deduced amino acid sequence of TraV indicated that it may be a lipoprotein; this was confirmed by examining the effect of globomycin on traV-encoded polypeptides synthesized in minicells. An open reading frame that may represent a previously undetected transfer gene, now designated trbG, was identified immediately upstream of traV. The deduced product of traR was found to share amino acid similarity with proteins from the bacteriophages 186 and P2 and with the dosage-dependent dnaK suppressor DksA. 相似文献
52.
53.
M Gaunt A Lloyd A Ross Naylor ND London PR Bell 《Canadian Metallurgical Quarterly》1998,16(6):543-545
Melorheostosis is a very rare bone disease of unknown etiology characterised by linear hyperostosis and associated with fibrosis of soft tissues and the skin. This uncommon sclerosing bone dysplasia was first described by Leri and Joanny in 1922, and since then, until 1993, approximately 300 cases were reported in the literature. Linear scleroderma is a localised proliferation of connective tissue and has rarely been associated with melorheostosis. In this paper, we present a new case of melorheostosis with linear scleroderma which, to the best of our knowledge, is the first case reported in Turkey. 相似文献
54.
The use of capillary electrophoresis (CE) for the separation of small organic molecules such as pharmaceutical agents and drug/xenobiotic metabolites has become increasingly popular. This has arisen, at least in part, from the complimentary mode of separation afforded by CE when compared to the more mature technique of HPLC. Other qualities of CE include relative ease of method of development, rapid analysis, and low solvent consumption. The recent introduction of a variety of detector systems (including UV diode array, laser-induced fluorescence, conductivity) and the demonstrated coupling of CE to MS have also aided acceptance of this technology. In the present report, we review the role of CE coupled to various detector systems including a mass spectrometer for the characterization of both in vitro and in vivo derived drug metabolite mixtures. Attributes of CE for this application are demonstrated by discussion of metabolism studies of the neuroleptic agent haloperidol. Various aspects of the development and use of CE and CE-MS for the characterization of haloperidol metabolites, including criteria for selection of parameters such as pH, ionic strength, extent of organic modification, and the use of nonaqueous capillary zone electrophoresis are discussed. We also consider potential limitations of CE and CE-MS for drug metabolism research and describe the introduction of membrane preconcentration-CE (mPC-CE) and mPC-CE-MS as a solution that overcomes the rather poor concentration limits of detection of CE methods without compromising the resolution of analytes or separation efficiency of this technique. 相似文献
55.
56.
The importance of extrapyramidal and mesolimbic function for circling behaviour was investigated by placing 6-hydroxydopamine (6-OHDA) and electrolesions in the cell bodies, axons and terminals of each system. Circling behaviour was weak when 6-OHDA was placed at the centre of the substantia nigra (SN), but the characteristic contralateral/ipsilateral turning to apomorphine/amphetamine were recorded. Circling was more marked when 6-OHDA was placed anterior to the SN but was generally absent following injections posterior to the SN. However, 6-OHDA placed in the medial forebrain bundle in the lateral hypothalamus resulted in intense contralateral/ipsilateral turning to apomorphine/amphetamine. Generally, the intensity of circling responses was related to the degree of striatal dopamine (DA) depletion but the more effective lesions also caused reductions in mesolimbic DA content. However, circling was not observed following any 6-OHDA injection into the mesolimbic DA system and it is concluded that mesolimbic DA function is not essential for the initiation of circling. In contrast to the 6-OHDA lesions, rats circled ipsilateral to both apomorphine and amphetamine when the SN was damaged by electrocoagulation to cause marked depletion of striatal dopamine. Lesser depletions of striatal dopamine after electrocoagulation in different regions of the medial forebrain bundle were associated with a lower intensity of ipsilateral circling to both drugs. In general, the differences between 6-OHDA and electrolesions could not be explained by additional damage to ascending noradrenaline or 5-hydroxytryptamine pathways. Lower doses of apomorphine were effective in the 6-OHDA circling rats, and the ipsilateral striatum of such rats was more sensitive to directly applied DA. Higher doses of apomorphine were required to produce circling after chronic electrolesions which rendered the ipsilateral striatum insensitive to DA. The contralateral circling to apomorphine after 6-OHDA lesions was abolished by chronic but not by acute electrolesion of the SN. It is suggested that electrolesions of the SN cause different effects to 6-OHDA because they destroy neuronal pathways in addition to the dopaminergic nigrostriatal tract. These appear to be required for the expression of circling behaviour caused by stimulation of the denervated striatum. Whereas 6-OHDA lesions result in super-sensitivity of the denervated strital DA receptors, electrolesions may cause a hypo-sensitivity of the same receptor sites. 相似文献
57.
58.
59.
Transfer performance of teams was measured in a simulated radar-controlled aerial intercept task. Superior performance occurred after training on an independently organized task (as compared to that after training which required verbal interaction among controllers), and superior performance occurred in an independently organized transfer task. However, these 2 variables interacted such that performance on an interaction condition of the transfer task was equivalent to that on an independently organized task if prior training was under the independent task organization. Training task fidelity influenced performance only on the interaction transfer task, with superior performance following a high-fidelity training situation in which controllers could acquire the same skills to be required in transfer for communication to interceptor pilots. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
Stephen J. Gentry Alan Jones Jack G. Firth Peter Watts 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(1):375-381
A study has been made of the influence of catalyst composition on the gas phase oxidation of 2-picoline over mixed vanadium and molybdenum oxides supported on kieselguhr. It is shown that the formation of partial oxidation products is associated with the existence of a mixed oxide phase. The selectivity for the formation of pyridine-2-aldehyde reaches a maximum when one in six vanadium(V) ions in the V2O5 lattice is replaced by a molybdenum(VI) ion. It is suggested that the origin of the selectivity is the formation of isolated (V4+-O) species. 相似文献