全文获取类型
收费全文 | 1160篇 |
免费 | 0篇 |
专业分类
化学工业 | 5篇 |
能源动力 | 1篇 |
无线电 | 2篇 |
一般工业技术 | 2篇 |
冶金工业 | 1146篇 |
自动化技术 | 4篇 |
出版年
2023年 | 1篇 |
2016年 | 1篇 |
2006年 | 1篇 |
1999年 | 40篇 |
1998年 | 368篇 |
1997年 | 200篇 |
1996年 | 117篇 |
1995年 | 69篇 |
1994年 | 62篇 |
1993年 | 56篇 |
1992年 | 4篇 |
1991年 | 16篇 |
1990年 | 12篇 |
1989年 | 15篇 |
1988年 | 20篇 |
1987年 | 13篇 |
1986年 | 16篇 |
1985年 | 12篇 |
1983年 | 2篇 |
1982年 | 4篇 |
1981年 | 6篇 |
1980年 | 10篇 |
1979年 | 1篇 |
1978年 | 2篇 |
1977年 | 34篇 |
1976年 | 75篇 |
1975年 | 2篇 |
1955年 | 1篇 |
排序方式: 共有1160条查询结果,搜索用时 15 毫秒
91.
92.
93.
PURPOSE: To determine whether (D)-penicillamine is effective in reducing hepatic oxalate production and urinary oxalate excretion. MATERIALS AND METHODS: (D)-Penicillamine was administered orally to rats to determine its effect on urinary oxalate excretion and used in isolated rat hepatocytes to investigate the effect of (D)-penicillamine on oxalate production from glycolate. Studies involving hepatic aminotransferases and hepatocytes isolated from (D)-penicillamine treated rats were used to clarify the discrepancy between the in vitro and in vivo results. RESULTS: In hepatocytes (D)-penicillamine lead to a significant reduction in oxalate production from glycolate. In vivo however. (D)-penicillamine led to a significant increase in urinary oxalate excretion and a decrease in plasma aminotransferase activity. Hepatic aminotransferases are involved in diverting oxalate precursors from oxalate production. In vitro, (D)-penicillamine was shown to inhibit hepatic aminotransferases. Hepatocytes isolated from (D)-penicillamine-treated rats produced significantly more oxalate than controls. CONCLUSIONS: These results indicate that (D)-penicillamine increases hepatic oxalate production and urinary oxalate excretion. (D)-penicillamine therefore has no therapeutic potential for reducing endogenous oxalate production and urinary oxalate excretion. Moreover, in conditions such as Wilson's Disease which is often associated with hypercalcuria, its use may be contraindicated. 相似文献
94.
95.
DE Anderson G St-Jean DC Richardson RM DeBowes JK Roush SR Lowry PW Toll HM Aberman DC Van Sickle JJ Hoskinson 《Canadian Metallurgical Quarterly》1997,68(6):571-576
The analysis of health state of drivers sent for an extra health examination for the estimation of driving capability for the driving of motor vehicle in alcoholic state was presented. The study included 380 drivers who were found driving drunk by traffic police (studied group) and 180 drivers of control group sent for an extra health examination for some other reason. The disorders in psychomotor sphere were noticed in the drivers of studied group and it was determined that they had caused significantly larger number of traffic accidents in last five-year period compared to the drivers of control group. The alcohol consumption in driving population represents significant medical, social, economic and traffic problem. The control of driver's alcoholism, the sending of alcoholic drivers to an extra health examination for the repeated estimation of driving capability and including in therapeutic and health-educational program can present significant measure of the primary prevention of road traffic traumatism which is on the constant increase. 相似文献
96.
97.
JB Kotch DC Browne CL Ringwalt V Dufort E Ruina PW Stewart JW Jung 《Canadian Metallurgical Quarterly》1997,21(11):1025-1037
OBJECTIVE: The purpose of this research was to determine whether risk factors for a maltreatment report in the first year of life, especially the interaction of life event stress and social support, persist into the second and third years of life. METHOD: Predominantly low income mothers who had been interviewed shortly after the birth of infants in a longitudinal cohort were re-interviewed around the infants' first birthdays, and reports to North Carolina's Central Registry of Child Abuse and Neglect were tracked for substantiated maltreatment reports. RESULTS: Variables significantly associated with a substantiated maltreatment report in the second or third year of life (p < .01) were first year maltreatment reports and participation in Medicaid. Three interactions between a stressful life event indicator variable and a social support indicator variable were significant predictors of substantiated second or third year reports (p < .05). CONCLUSIONS: Even in the presence of significant risk factors from the first year of life, life event stress can increase the risk of a substantiated maltreatment report in the second or third years of life, but social support may moderate the effect of life events. 相似文献
98.
A 91-year-old Chinese man developed bilateral lower limb oedema due to venous obstruction resulting from a distended urinary bladder. After the bladder was decompressed by urethral catheterisation, the bilateral lower limb oedema promptly subsided. Although a distended urinary bladder is a rare cause of bilateral lower limb oedema, it can be easily recognised by palpation of the lower abdomen and the relief of symptoms by urethral catheterisation is most rewarding. 相似文献
99.
100.
Tear cytokines and growth factors are likely to modulate the wound healing process following corneal epithelial injury. Hepatocyte growth factor (HGF) is a paracrine mediator of epithelial proliferation, motility, and differentiation that is produced by keratocytes and the lacrimal gland. Tear samples were collected preoperatively and one, two, and seven days postoperatively in eyes undergoing excimer laser surface ablation [photorefractive keratoplasty (PRK) or phototherapeutic keratoplasty (PTK)]. Tear HGF concentration was measured with a sensitive ELISA assay. Tear HGF production was calculated using the tear flow rate in the collection capillary and HGF concentration. Although the instantaneous concentration of HGF in tears decreased significantly in the days following PRK, a large increase in tear flow resulted in a marked increase in HGF bioavailability. The heparin-binding characteristics of HGF would result in increased binding to glycosaminoglycans and other heparin-like matrix components and, therefore, increased growth factor availability to the cognate recptor. This is the first report documenting changes in tear film HGF production. HGF may have an important function in maintenance and wound healing of the ocular surface epithelium since HGF is present in the normal tear film and the HGF secretion rate increases markedly in parallel with aqueous tear production following corneal surgical injury. 相似文献