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781.
A collaborative study of the site-specific natural isotope fractionation-nuclear magnetic resonance (SNIF-NMR) method for detecting added beet sugar in fruit juices is reported. This method is complementary to the stable carbon isotope ratio analysis (SCIRA) (AOAC Official Methods 981.09 and 982.21), which can detect sugars derived from plants exhibiting C4 metabolism (corn and sugarcane). It is based on the fact that the deuterium content at specific positions of the sugar molecules is higher in fruit sugars than in beet sugar. The fruit juices are fermented, and the alcohol is distilled with a quantitative yield and analyzed with a high-yield NMR spectrometer fitted with a deuterium probe and fluorine lock. The proportion of ethanol molecules monodeuterated on the methyl site is recorded. This parameter (D/H)I is lowered when beet sugar is added to a fruit juice or concentrate. The precision of that method for measuring (D/H)I was observed to be similar to that of other isotope ratio methods: Sr values ranged from 0.19 to 0.25 ppm and SR values varied between 0.21 and 0.37 ppm. An excellent correlation was observed between the percentage of added beet sugar and the (D/H)I isotope ratio measured in this collaborative study. Consequently, all samples in which beet sugar was added were found to have a (D/H)I isotope ratio significantly below the normal value for authentic juice or concentrate of that fruit. The SNIF-NMR method for detection of added beet sugar in fruit juices has been adopted by AOAC INTERNATIONAL. 相似文献
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783.
We provide evidence of direct transfer of functional DNA from bacteria to mammalian cells. An Escherichia coli K12 diaminopimelate auxotroph made invasive by cloning the invasin gene from Yersinia pseudotuberculosis transfers DNA after simple co-incubation, into a variety of mammalian cell lines. Transfer efficiency was enhanced in some cells by coexpression of the gene for listeriolysin from Listeria monocytogenes. Expression of the acquired genes occurs in both dividing and quiescent cells. The only requirement for bacteria to transfer genetic material into nonprofessional phagocytic cells and macrophages is the ability to invade the host cell. 相似文献
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785.
The characterization of algal and microbial mucilages and their aggregates in aquatic ecosystems 总被引:1,自引:0,他引:1
GG Leppard 《Canadian Metallurgical Quarterly》1995,165(1-3):103-131
The mucilage 'phenomenon' of marine waters, a sporadic but massive accumulation of gelatinous material at and below the water surface, can create serious environmental and economic problems. To address these problems, we must understand better the causes of the phenomenon, its modulation by environmental factors and its adverse effects on ecosystems. In the context of an improved understanding, this brief review describes the means to characterize mucilage types and mucilage aggregates in their native condition, or as close to native as state-of-the-art technology will permit. Biological, chemical and physical factors interact to determine mucilage 'speciation' and thus the specific properties of mucilaginous materials. These factors and their interactions are described briefly in relation to the molecular biology of mucilage synthesis, the formation of submicroscopic 'particles' of mucilage and the morphology of mucilage aggregates. To facilitate current attempts to relate mucilage fine structure to the macroscale morphology of large aggregates (e.g., as found in the Adriatic Sea), attention will be focused on the 'fibril', a ribbon-like colloid rich in polysaccharide molecules. Such colloids (submicrometre particles) present many morphotypes which are identifiable by transmission electron microscopy; several fibril types appear as basic structural units in many kinds of mucilage aggregates in aquatic ecosystems. Attention will also be focused on (1) the problems of coping with analyzing mixtures of highly-hydrated, physically-unstable materials and (2) the detection, assessment and minimization of colloid instability artifacts which have confounded morphological analyses of mucilage aggregates in the past. 相似文献
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787.
788.
NF Vorob''eva GG Kniazev VA Lazarev VK Spiridonov 《Canadian Metallurgical Quarterly》1997,111(2):59-63
Attitudes to health and illness may differ between rural and urban dwellers. Issues that may relate to the provision of health services to rural dwellers are raised for consideration. The response of urban dwellers to illness or disability has often been linked to discomfort caused by pain or cosmetic attractiveness, while for rural dwellers the response to illness or disability is often related to the degree to which the illness or disability affects productivity. Often the rural resident will postpone seeking medical or associated services until it is economically or socially convenient. The notion of exposing their private lives to strangers or acquaintances from the local based services or to undertake the journey to distant services where the cultural or behavioural differences could be misunderstood, may impact on rural dwellers' well-being. Health service providers in rural areas need to understand such differences and difficulties when offering services. 相似文献
789.
RL de Paula MC Giorgi J Soares Júnior AP Moraes M Izaki GG Cerri F Pileggi JC Meneghetti 《Canadian Metallurgical Quarterly》1997,68(3):163-166
Children with acute otitis media (AOM), aged 2-12 years, were randomised to 10 days treatment with amoxycillin/clavulanate (A/C) 70/10 mg/kg/day given b.i.d. (231 patients) or to A/C 60/15 mg/kg/day given t.i.d. (232 patients). Clinical success rates at end of therapy (10-17 days) were 91.8% for the b.i.d. group and 90.5% for the t.i.d. group and at follow-up (28-42 days) were 80.1% for the b.i.d. group and 77.6% for the t.i.d. group, indicating that the b.i.d. regimen was as effective as the t.i.d. regimen. There was no statistically significant difference in incidence of adverse experiences between the two groups. The overall incidence of protocol defined diarrhoea assessed from diary booklets was low, with a lower incidence in the b.i.d. group (6.7%) than in the t.i.d. group (10.3%). Significantly more patients in the b.i.d. group (83.1%) than in the t.i.d. group (72.8%) had at least 80% compliance over a 7-10 day treatment period. A/C given twice or three-times daily was highly effective in the treatment of AOM in children. The two regimens showed equivalent clinical efficacy, both were well tolerated, and there was evidence of improved compliance with the b.i.d. regimen. 相似文献
790.
Skip lesions in temporal arteritis 总被引:3,自引:0,他引:3
Although isolated foci of arteritis ("skip lesions") are presumed to occur in temporal arteritis, there is little documentation of their existence or significance. We have identified skip lesions in 17 of 60 patients (28%) with temporal arteritis, based on a retrospective and prospective examination of temporal artery biopsy specimens. By examining more than 6,000 serial sections of arteries from patients with skip lesions, we have found foci or arteritis as short as 330 mu in length in an otherwise normal biopsy specimen. Our study emphasizes the need to biopsy long segments of artery, to examine multiple histologic sections, and to perform a contralateral temporal artery biopsy when frozen-section examination of the first side is normal. 相似文献