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21.
E García R Calvo JM Rodríguez-Sasiaín R Jiménez IF Trocóniz E Suárez 《Canadian Metallurgical Quarterly》1995,39(8):1019-1023
The influence of altered protein binding on the neuromuscular effect of atracurium has been studied in rats with experimental inflammation induced by subcutaneous injection of turpentine oil. Doses of atracurium ranging from 0.45 to 1.5 mg.kg-1 were administered to control (n = 30) and to experimental inflammation induced rats (n = 30). Neuromuscular transmission was monitored by recording the twitch tension of the tibialis-anterior muscle elicited by stimulation of the sciatic nerve. Three effect parameters were recorded: (i) intensity of the effect, measured as percentage depression of baseline twitch tension, (ii) duration of drug action (min) and (iii) recovery time (min). The dose-intensity of the effect relationship was modelled using a sigmoid Emax model. The ED50 (effective dose eliciting 50% of the maximum effect) was significantly increased (P < 0.01) in the inflammation group as compared to the control group (0.94 vs. 0.68 mg.kg-1). This change was reflected in a shift of the dose-response curve to the right in the pretreated rats. For equipotent doses ED95 (defined as the effective dose eliciting 95% of maximum effect), no differences were found in recovery time and duration of action between the two groups of rats. Mucoproteins levels (index of alpha 1-acid glycoprotein (AAG) and protein binding were significantly increased in rats with experimental inflammation as compared to control rats. Based on these results, altered serum protein binding of atracurium appears to be responsible, at least in part, for the resistance to atracurium. 相似文献
22.
The need to defluoridate and fluoridate the water supplies in areas with drinking water naturally containing above-optimal (>/=2.5 mg/l) and suboptimal (=0.3 mg/l) fluoride concentration and caries and fluorosis prevalence of 12-year-old schoolchildren were assessed in Italy. In the low-fluoride area, 48.4% children were caries-free (DMFT = 0) and the DMFT and DMFS were 1.5 and 2.6; in the high-fluoride area, 46.8% had a DMFT = 0 and the values of the indices were 1.4 and 1.6, respectively. Multiple logistic regression analysis showed a significant association in the caries-free status according to parents' employment status (OR = 1.2, 95% CI = 1.1-1.3) and children's sweets consumption, since children who consumed sweets at least once a day had an adjusted odds ratio of 1.8 (95% CI = 1.4-2.3) compared to those with a lower consumption. Multiple linear regression analysis showed that DMFT and DMFS were significantly higher in children with a lower socioeconomic status and in those who consumed sweets at least once a day, with the DMFS significantly associated also with the area of residence. DT and FT scores were higher in the high- and low-fluoride areas, respectively. No evidence of fluorosis was reported in 94.5 and 55.3% of children in the low- and high-fluoride areas, respectively. The Community Fluorosis Index (CFI) for all permanent teeth was significantly higher in the high-fluoride area, 0.8, than the value, 0.1, found in the low-fluoride community. Our results substantiate the difficulties in defining universal guidelines for the fluoridation or defluoridation of drinking water and the need for an epidemiological approach to the decision as to fluoridate and defluoridate the water supply. 相似文献
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TL Goldsworthy L Recio K Brown LA Donehower JC Mirsalis RW Tennant IF Purchase 《Canadian Metallurgical Quarterly》1994,22(1):8-19
Recent advances have been made in the characterization of a number of transgenic animal models. These animal models have provided a powerful toxicological tool for studying in vivo chemical effects and have increased our understanding of the role of specific genetic alterations as predisposing factors for chemical carcinogenesis. The goal of this symposium was to introduce the development of transgenic animals and the utilization of transgenics in toxicology research focusing on understanding tissue-specific mutation, chemical effects, and cancer. The production of transgenic animals, including gene insertions and gene knockouts, and the utilization of transgenic technology for studying multistage carcinogenesis and tumor suppressor genes are described. Data on the application and implications of transgenics as a genetic endpoint are also discussed. The use of transgenic animals in toxicology should improve our understanding of the role of specific genetic alterations in the carcinogenic process and lead to improved estimations of human health risks. 相似文献
26.
IF Pollack RC DaRosso PL Robertson RL Jakacki JR Mirro J Blatt S Nicholson RJ Packer JC Allen A Cisneros VC Jordan 《Canadian Metallurgical Quarterly》1997,3(7):1109-1115
Recent studies have indicated that the proliferation of malignant gliomas is in part dependent on excessive activation of protein kinase C (PKC)-mediated pathways. Conversely, inhibiting PKC may provide a novel approach for blocking glioma growth. The antiestrogen tamoxifen, a moderately potent PKC inhibitor, has been shown in vitro to block the proliferation of malignant glioma cell lines at concentrations several-fold higher than those typically attained during the treatment of breast cancer; such serum concentrations may be achieved with doses > 40 mg/m2 b.i.d. The safety and efficacy of these high doses for producing disease control in patients with malignant gliomas has recently been noted anecdotally, although a rigorous study of this agent has been lacking. To address this issue, we examined the safety and efficacy of high-dose tamoxifen in a series of children with malignant gliomas that had progressed after conventional therapy. An initial group was treated with 60 mg/m2 p.o. b.i.d. and a second group with 100 mg/m2 b.i.d. Steady-state serum tamoxifen and metabolite levels were measured in most patients. Toxicity with the regimen was minimal; two patients treated at the higher dose required reduction to the lower dose because of asymptomatic prolongation of the QT interval on an electrocardiogram. Although none of the patients exhibited clear-cut tumor regression, 4 of 14 patients had stabilization of previously progressive disease for at least 3 months; the longest survivor lived for 17 months after beginning tamoxifen. The moderate efficacy of this agent in otherwise end-stage disease coupled with its low toxicity and the relative ease of oral administration provides a rationale for proceeding with larger studies of this agent in patients with malignant gliomas, possibly as a means for potentiating the effects of conventional chemotherapeutic agents, which to date have shown limited efficacy in the treatment of these tumors. 相似文献
27.
VA Kholodny? IF Syrbu MM Militsa VP Kovalenko VO Zhulin'sky? OV Kapshytar 《Canadian Metallurgical Quarterly》1997,(11-12):10-11
While examination of 83 patients it was established that in the presence of complicated gastric and duodenal ulcer disease the secondary immune deficiency is developing, which deepens after the surgical intervention conduction. Tiotriazolin, promoting the immune system state and the blood biochemistry indexes normalization, the immune system state and the blood biochemistry indexes stimulation, hemopoiesis stimulation, the treatment results improvement, was applied for immunomodulation. 相似文献
28.
SM Liapunov IF Seregina OI Okina VV Golubchikov IV Kislova AA Kistanov EP Shevchenko NM Sorokina 《Canadian Metallurgical Quarterly》1998,(12):37-44
The authors specified methods to detect lead in biologic materials. The quality control covered use of Russian and foreign standard samples, the results proved to agree. Lead was detected by AAS technique (direct and flow-type variants with preliminary concentration of lead) and ELRA method. The authors determined measurement limits sufficient for analysis of complex biologic materials. The measurement range for lead varied from 0.002 mg/kg (plants) to 3,000 mg/kg (soil); the range of serum lead levels was < 0.5-39 mg/dl. 相似文献
29.
Cot death (sudden infant death syndrome) is one of the most common causes of death in the first year of life. Four cases with a pathological fear of cot death are presented. All the patients were depressed and in 2 cases the fear of cot death had an obsessional quality. In all cases there were complications during pregnancy (miscarriage, threatened abortion, recurrent vomiting in last trimester). In 1 case, the patient knew 3 mothers who had suffered cot deaths; in another, the infant was gravely ill in the neonatal period. Pathological fear of cot death can be recognised by the presence of two central features - overvigilance and excessive nocturnal checking of the baby's breathing. Therapeutic interventions are discussed. 相似文献
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