全文获取类型
收费全文 | 86篇 |
免费 | 0篇 |
专业分类
化学工业 | 3篇 |
金属工艺 | 1篇 |
机械仪表 | 2篇 |
建筑科学 | 1篇 |
能源动力 | 1篇 |
无线电 | 3篇 |
一般工业技术 | 13篇 |
冶金工业 | 57篇 |
原子能技术 | 2篇 |
自动化技术 | 3篇 |
出版年
2019年 | 1篇 |
2016年 | 1篇 |
2015年 | 1篇 |
2012年 | 2篇 |
2011年 | 1篇 |
2008年 | 1篇 |
2005年 | 1篇 |
2002年 | 1篇 |
2000年 | 2篇 |
1999年 | 5篇 |
1998年 | 25篇 |
1997年 | 10篇 |
1996年 | 3篇 |
1995年 | 1篇 |
1994年 | 4篇 |
1993年 | 3篇 |
1992年 | 1篇 |
1988年 | 1篇 |
1986年 | 2篇 |
1985年 | 1篇 |
1984年 | 2篇 |
1982年 | 2篇 |
1981年 | 2篇 |
1980年 | 1篇 |
1979年 | 1篇 |
1978年 | 1篇 |
1977年 | 3篇 |
1976年 | 3篇 |
1973年 | 2篇 |
1972年 | 1篇 |
1968年 | 1篇 |
排序方式: 共有86条查询结果,搜索用时 15 毫秒
41.
42.
MO MCarron KW Muir CJ Weir AG Dyker I Bone JA Nicoll KR Lees 《Canadian Metallurgical Quarterly》1998,29(9):1882-1887
BACKGROUND AND PURPOSE: Polymorphism of the apolipoprotein E gene (APOE) may influence outcome after traumatic brain injury and intracerebral hemorrhage, with the epsilon4 allele being associated with poorer prognosis. We investigated APOE allele distribution in acute stroke and the effect of the epsilon4 allele on outcome. METHODS: APOE genotypes were determined in 714 stroke patients: 640 ischemic stroke and 74 intracerebral hemorrhage patients. The survival effect of the epsilon4 allele was assessed with the use of a stratified log-rank test. A Cox proportional hazards regression model was used to estimate the independent effect of epsilon4 dose (0, 1, or 2) on survival, and logistic regression was used to determine the effect on 3-month outcome (good if alive at home, poor if in care or dead). RESULTS: Allele distribution matched the general population with no difference between the ischemic and hemorrhagic groups. Survival in the entire cohort was unaffected by epsilon4 dose. Improved survival with increasing epsilon4 dose was found in the ischemic group (relative hazard=0.76 per allele; P=0.04). If transient ischemic attacks were excluded, a trend for improved survival persisted (P=0.06). With intracerebral hemorrhage, a trend was seen toward reduced survival with epsilon4 (P=0.07, log-rank test). Three-month outcome in the ischemic group was unaffected by epsilon4 dose, and a trend toward poorer outcome with epsilon4 was seen for intracerebral hemorrhage (P=0.10). CONCLUSIONS: The APOE epsilon4 allele had divergent effects on survival and outcome in ischemic and hemorrhagic strokes in this population. The reported adverse effect on patients with intracerebral hemorrhage was supported. The favorable survival effect on ischemic stroke patients requires further study. 相似文献
43.
We found a novel maternally inherited T3308C mutation in the mtDNA ND1 gene in a patient with bilateral striatal necrosis and stroke-like episodes. Muscle biopsy from the proband showed mitochondrial proliferation in blood vessels and normal respiratory chain activities. The mutation, which was not present in 100 normal controls or in 30 patients with mitochondrial disease, was heteroplasmic in both muscle and blood of the proband and in blood from her asymptomatic mother. This mutation results in a Met --> Thr change at the highly conserved amino acid position 1. The T3308C mutation may alter the hydrophobicity and antigenicity of the N-terminal peptide of ND1. 相似文献
44.
45.
The molecular mechanisms underlying long-term potentiation in the hippocampus have received much attention because of the likely functional importance of synaptic plasticity for information storage and the development of neuronal connectivity. Surprisingly, it remains unclear whether activity modifies the strength of individual synapses in a digital (all-or-none) or analog (graded) manner. Here we characterize step-like all-or-none transitions from baseline synaptic transmission to potentiated states following protocols for inducing potentiation at putative single CA3-CA1 synaptic connections. Individual synapses appear to have all-or-none potentiation indicative of highly cooperative processes but different thresholds for undergoing potentiation. These results raise the possibility that some forms of synaptic memory may be stored in a digital manner in the brain. 相似文献
46.
Sfigakis F. Paddon P. Pacradouni V. Adamcyk M. Nicoll C. Cowan A.R. Tiedje T. Young J.F. 《Lightwave Technology, Journal of》2000,18(2):199-202
The optical transmission in the range 900-1600 nm was measured through thick (~1 μm) layers of Al0.98Ga0.02As wet-oxidized at 375°C on GaAs. The spectra are fit well by neglecting absorption, and using 1.61 for the refractive index 相似文献
47.
N Connor M Catchpole PA Rogers N Macdonald C Mc Garrigle I Simms L Radcliffe V Gilbart SE Clarke J Webster A Nicoll 《Canadian Metallurgical Quarterly》1997,7(12):R173-R178
A profile of sexually transmitted diseases (STDs) and HIV infections among teenagers in England and Wales was obtained from reports of newly diagnosed STDs among teenagers attending genitourinary medicine (GUM) clinics in 1995, laboratory reports of newly diagnosed HIV infections between 1985 when reporting began and the end of 1995, and the prevalence of HIV (unlinked anonymous programme) among teenagers attending genitourinary medicine clinics and antenatal clinics in 1994 and 1995. STD reports were analysed by sex, age group, and place of residence of patients--whether in the NHS Thames regions or elsewhere in England and Wales. High rates of STDs were reported in teenagers, particularly in girls. The incidences of gonorrhoea, chlamydia infection, and first attack genital wart infections were higher in teenage girls than in any other age group. Boys under 16 years of age had substantially higher rates of infection with all STDs in the Thames regions than elsewhere. Rates of gonorrhoea in teenagers of both sexes in the Thames regions were more than twice those in the rest of the country. Infection rates for genital herpes, and chlamydia in girls, were also higher in the Thames regions, although the geographical differences were less marked. The seroprevalence of HIV among heterosexual teenagers was very low. In contrast, 226 HIV infections among teenage boys had probably been acquired through sexual intercourse with other males. Unlinked anonymous testing revealed HIV antibody in 7.5% of routinely collected serology specimens taken from teenage homosexual or bisexual males attending GUM clinics in London. The high rates of STDs among teenage girls and all teenagers in the Thames regions make these groups a high priority for sexual health promotion, with special consideration given to homo/bisexual male teenagers. Detailed surveillance of risk factors for STDs, and further studies of teenage sexual behaviour will help to effectively target resources to improve the sexual health of teenagers in England and Wales. 相似文献
48.
AE Doering DA Nicoll Y Lu L Lu JN Weiss KD Philipson 《Canadian Metallurgical Quarterly》1998,273(2):778-783
The cardiac Na+/Ca2+ exchanger, NCX1, has been modeled to consist of 11 transmembrane segments and a large cytoplasmic loop (loop f). Cysteine mutagenesis and sulfhydryl modification experiments demonstrate that the loop connecting transmembrane segments 1 and 2 (loop b) is located on the cytoplasmic side of the membrane, as previously modeled. A mutation in loop b, asparagine 101 to cysteine (N101C), renders the exchanger insensitive to regulation by cytoplasmic Na+ and Ca2+. Nearby mutations at residue threonine 103 (T103C or T103V) increase the apparent affinity of the exchanger for cytoplasmic Na+ and also produce a significant Li+ transport capacity. The evidence suggests that the region at the interface of cytoplasmic loop b and transmembrane segment 2 is important in Na+ transport and also in secondary regulation. Thus, this region may form part of the link between the ion translocation pathway formed by the transmembrane segments and regulatory sites that have previously been localized to loop f. 相似文献
49.
GO Rankin KW Beers DW Nicoll DK Anestis SK Hong JL Hubbard JG Ball MA Valentovic PI Brown 《Canadian Metallurgical Quarterly》1996,108(1-2):109-123
Nephrotoxicity occurs following intraperitoneal (i.p.) administration of 2-chloroaniline or 4-chloroaniline hydrochloride to Fischer 344 rats, but the nephrotoxicant chemical species and mechanism of nephrotoxicity are unknown. The purpose of this study was to evaluate the in vivo and in vitro nephrotoxic potential of 2-amino-5-chlorophenol and 4-amino-3-chlorophenol, metabolites of 4-chloroaniline and 2-chloroaniline. A comparison was also made between the nephrotoxic potential of the aminochlorophenols and the corresponding aminophenols to examine the effect of adding a chloride group on the nephrotoxic potential of the animophenols. Male Fischer 344 rats (4/group) were given an i.p. injection of a chloroaniline or aminochlorophenol hydrochloride (1.5 mmol/kg), and aminophenol (1.0 or 1.5 mmol/kg), or vehicle, and renal function monitored at 24 and 48 h. Both aminochlorophenols induced smaller and fewer renal effects that the parent chloroanilenes in vivo. Also, 4-aminophenol was markedly more potent as a nephrotoxicant that 4-amino-3-chlorophenol, while 2-aminophenol and 2-amino-5-chlorophenol induced only mild change in renal function. In vitro, the phenolic compounds reduce p-aminohippurate accumulation by renal cortical slices at bath concentrations of 0.01 mM, while a bath concentration of 0.50 mM or greater was required for the chloroanilines. However, all compounds reduced tetraethylammonium accumulation at bath concentrations of 0.1-0.5 mM or greater. These results indicate that extrarenally-produced aminochlorophenol metabolites do not contribute to the mechanism of chloroaniline nephrotoxicity. Also, the reduced nephrotoxic potential of 4-amino-3-chlorophenol compared to 4-aminophenol could result from an altered ability of the aminochlorophenol to redox cycle or form conjugates. 相似文献
50.
DM Wu Y Zhang NA Parada H Kornfeld J Nicoll DM Center WW Cruikshank 《Canadian Metallurgical Quarterly》1999,162(3):1287-1293
IL-16 is synthesized as a precursor molecule of 68 kDa (pro-IL-16) that is processed by caspase-3, a member of the IL-1 converting enzyme (ICE) family. This cleavage results in a 13-kDa carboxy terminal peptide, which constitutes the bioactive secreted form of IL-16. We have previously reported constitutive IL-16 mRNA expression and pro-IL-16 protein in CD4+ and CD8+ T cells. Although bioactive IL-16 protein is present in unstimulated CD8+ T cells, there is no bioactive IL-16 present in CD4+ T cells. Along these lines, unstimulated CD8+ T cells contain active caspase-3. In the current studies we investigated the regulation of IL-16 protein and mRNA expression in CD4+ T cells and determined the kinetics of secretion following stimulation of the TCR. CD4+ T cells release IL-16 protein following antigenic stimulation, and this release is accelerated in time by costimulation via CD28. However, CD3/CD28 costimulation did not alter IL-16 mRNA appearance or stability in either CD4+ or CD8+ T cells. The secretion of bioactive IL-16 from CD4+ T cells correlated with the appearance of cleavage of pro-caspase-3 into its 20-kDa active form. Thus, resting CD8+ T cells contain active caspase-3 that is capable of cleaving pro-IL-16, whereas CD4+ T cells require activation for the appearance of active caspase-3. The mechanism of release or secretion of bioactive IL-16 is currently unknown, but does not correlate with cellular apoptosis. 相似文献