首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   193篇
  免费   2篇
化学工业   1篇
轻工业   6篇
石油天然气   2篇
冶金工业   186篇
  2020年   1篇
  2019年   2篇
  2018年   2篇
  2011年   1篇
  2004年   1篇
  1999年   3篇
  1998年   48篇
  1997年   23篇
  1996年   28篇
  1995年   13篇
  1994年   9篇
  1993年   16篇
  1992年   3篇
  1991年   4篇
  1990年   6篇
  1989年   4篇
  1988年   4篇
  1987年   5篇
  1986年   1篇
  1985年   1篇
  1980年   3篇
  1977年   5篇
  1976年   12篇
排序方式: 共有195条查询结果,搜索用时 15 毫秒
41.
42.
The effect of pentoxifylline (PTX) was tested for its capacity to modulate cytokine responses during therapy of severe Plasmodium falciparum malaria in a placebo-controlled, randomized study in 45 adult patients in Bangkok, Thailand. The patients received standard antimalarial treatment with artesunate (120 mg intravenously given immediately, then 60 mg every 12 hr for a total dose of 600 mg). The patients received either low-dose PTX (20 mg/kg/day, n = 15), high-dose PTX (40 mg/kg/day, n = 15), or placebo (n = 15) as continuous infusion for the first three days of antimalarial treatment. Tumor necrosis factor (TNF) and interleukin-6 (IL-6) plasma levels were markedly elevated in all patients prior to treatment. After 6 hr of high-dose PTX treatment, TNF and IL-6 levels significantly decreased while an increase in TNF and IL-6 levels was seen after 6 hr of low-dose PTX or placebo treatment (P < 0.01). After 12 and 24 hr of high-dose PTX infusion, TNF-receptor plasma concentrations were lower than in low-dose PTX- or placebo-treated patients (P < 0.01), whereas no differences between the groups with regard to IL-6 receptor levels were observed. We conclude that 40 mg/kg/day of PTX reduces plasma levels of TNF, IL-6, and TNF-receptor in patients with severe malaria. Whether this reduction improves clinical outcome remains to be determined.  相似文献   
43.
PURPOSE: The purpose of the study was to examine the effect of T-lymphocyte products on human retinal pigment epithelial (HRPE) cell interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) secretion and gene expression. METHODS: HRPE cells were stimulated for 2, 4, 8, or 24 hours with 20% conditioned media (CM) from T-lymphocytes stimulated with CD3 or CD28 monoclonal antibodies (mAbs) or phorbol myristic acid. In some experiments, CM from CD3 mAb-stimulated T-lymphocytes was preincubated with neutralizing anti-(alpha)-tumor necrosis factor (TNF), alpha-interferon-gamma (IFN-gamma), or alpha-interleukin-1 (IL-1) mAb (control) to determine the contributions of each of these cytokines to HRPE chemokine induction by stimulated T-lymphocyte CM. HRPE cells were stimulated for 8 and 24 hours with IL-1 beta (0.2 to 20.0 ng/ml) (positive control), TNF-alpha (0.2 to 20.0 ng/ml) (positive control), IFN-gamma (1 to 1000 U/ml), IFN-gamma + IL-1 beta, IFN-gamma + TNF-alpha. Interleukin-2 (IL-2; 100 ng/ml) alone or in combination with IL-1 beta, TNF-alpha, or IFN-gamma also was tested. Enzyme-linked immunosorbent assay (ELISA) and Northern blot analyses were performed to determine secreted IL-8 and MCP-1 and their steady state mRNA expression, respectively. RESULTS: ELISA showed significant increases in HRPE IL-8 and MCP-1 secretion by CM from T-lymphocytes stimulated with CD3 or CD3 + CD28 mAb. Smaller, but significant, increases in IL-8 and MCP-1 resulted from CM phorbol myristic acid-stimulated T-lymphocytes. CM preincubated with neutralizing alpha-TNF or alpha-IFN-gamma mAb induced significantly less HRPE IL-8 and MCP-1, whereas preincubation of CM with neutralizing alpha-IL-1 mAb failed to inhibit CM-induced IL-8 or MCP-1. Northern blot analysis showed increased HRPE IL-8 and MCP-1 mRNA expression within 2 hours of stimulation and was maintained up to 24 hours. CM from T-lymphocytes stimulated with CD3 mAb or CD3 + CD28 mAb produced the greatest increases in IL-8 and MCP-1 mRNA. IFN-gamma induced dose-dependent increases in HRPE MCP-1, but not IL-8, IFN-gamma potentiated IL-1 beta and TNF-alpha-induced MCP-1 production, but showed little modulation of IL-1 beta and TNF-alpha-induced IL-8 production. IL-2 did not induce HRPE IL-8 or MCP-1, nor did it modulate the effects of the other cytokines. Northern blot analysis confirmed the ELISA results. CONCLUSIONS: T-lymphocyte secretions induce HRPE IL-8 and MCP-1 gene expression and secretion. TNF and IFN-gamma appear to be necessary components of T-lymphocyte CM for the induction of HRPE IL-8 and MCP-1. IFN-gamma alone induces HRPE MCP-1, albeit to a lesser extent than would IL-1 beta or TNF-alpha, and potentiates IL-1 beta- and TNF-alpha-induced HRPE MCP-1. IL-2 does not appear to modulate cytokine-induced HRPE IL-8 or MCP-1.  相似文献   
44.
A micellar electrokinetic capillary chromatographic method was set up for the quality control of rhubarb and its preparations. Anthraquinone derivatives were separated successfully within 10 min in the buffer solution of 50 mmol/L H3BO3-NaOH (pH 11) containing 25 mmol/L sodium deoxycholate. The established method, with a recovery of extraction of over 90%, has good linear relationship and reproducibility. The contents of anthraquinone derivatives in rhubarb and a tablet of Niu-huang-jie-du differed significantly, showing that the quality control of rhubarb and its preparations is necessary.  相似文献   
45.
Adult American women as a group tend to gain weight with age, and many women report that their weight gain started around the time of their menopause. Moreover, as women age, there are changes in body composition that include losses in bone mineral and body cell mass, and increases in total body fat, visceral fat, and extracellular fluid. It appears as if these body composition changes begin or accelerate during the menopausal years. The importance of weight gain and changes in body composition are their associations with an increased risk of developing some malignancies, cardiovascular disease, osteoporosis, and several other clinical conditions. This overview describes selected studies of menopause and aging-associated weight gain, changes in body composition, and alterations of energy expenditure in women. Gaps in the present understanding of these changes are highlighted, and an emphasis is placed on new research methodologies for investigating body composition and energy expenditure in vivo. A concluding section of the report summarizes areas in need of future investigation.  相似文献   
46.
Genetic studies have suggested homogeneity between the Baltic-type and Mediterranean-type progressive myoclonic epilepsy. Magnetoencephalography was applied to elucidate the mechanism underlying the giant evoked responses in cortical reflex myoclonus. A new concept of negative myoclonus mediated by cortical reflex mechanism was proposed. Cortical myoclonus was demonstrated in various neurodegenerative or metabolic disorders, such as presenile or senile dementia, olivopontocerebellar atrophy, and myoclonus epilepsy associated with ragged-red fibres. Myoclonus in corticobasal degeneration is especially noteworthy because it has clinical and electrophysiological features of cortical reflex myoclonus, but its latency is shorter compared with the conventional cortical reflex myoclonus. Clinical features of 'palatal myoclonus' were reported by the name of 'palatal tremor'.  相似文献   
47.
48.
The cyclin dependent kinase 2 (Cdk2) is required for initiation and progression of DNA replication. Activation of Cdk2 involves binding to cyclin E or cyclin A and dephosphorylation of Tyr15. The present studies demonstrate that treatment of U-937 cells with 1-beta-D-arabinofuranosylcytosine (ara-C) is associated with tyrosine phosphorylation of Cdk2 and inhibition of Cdk2 activity. The results also demonstrate that Cdk2 directly associates with the Src-like tyrosine kinase Lyn as a consequence of ara-C-treatment. Confocal microscopy studies show that Lyn is detectable in the nucleus and that it colocalises with Cdk2. Subcellular fractionation and coimmunoprecipitation studies further demonstrate nuclear binding of Lyn and Cdk2. We also show that Lyn phosphorylates Tyr15 of Cdk2 and that incubation of Lyn with Cdk2 results in inhibition of Cdk2 activity. These findings suggest that the association of Lyn and Cdk2 in ara-C-treated cells may contribute to regulation of Cdk2-dependent cell cycle checkpoints.  相似文献   
49.
This paper describes a combined inpatient and partial hospital program, with a ten-bed short-term inpatient unit and a partial hospital program that can accommodate 24 patients. Inpatients and partial hospital patients are treated together by the same staff in a program located in the partial hospital. The authors highlight features of the program that address the five elements of continuity: place, personnel, program, patient-peers, and plan for treatment. The discussion focuses on the importance of continuity in sustaining a combined unit; potential benefits for patients, families, staff, and trainees; attractiveness to third-party payers; and impediments to fully realizing the potential of the unit.  相似文献   
50.
During the present study, thirty-eight children in Upper Egypt (less than 12years old) were admitted to Pediatric Intensive Care Unit for scorpion envenomation. They were compared with thirteen apparently healthy children of matching age as controls. The victims and controls were subjected to complete clinical examination and full blood count. The evaluations of the serum levels of interleukin-1beta (IL-1beta), interleukin-6 (IL-6), nitric oxide (NO) and alpha1-antitrypsin (alpha1-AT) were performed once for the controls and twice for the victims, the first sample on admission and the 2nd sample after 24 h. All victims showed significantly higher mean values of IL-1beta IL-6, NO, alpha1-AT and leucocytic count both on admission and on follow up when compared with controls. Manifestations of mild envenomation were detected among 28.9% of the victims, while 71.1% of the victims manifested severe scorpion envenomation. The severely envenomated children showed significantly higher mean values of IL-1beta, IL-6, NO, alpha1-AT and leucocytic count both on admission and on follow up when compared with mild cases. The case fatality rate in the current study was 7.8%. The non-surviving victims showed significantly higher mean values of IL-1beta, IL-6 and leucocytic count both on admission and on follow up in comparison to the survivors. Furthermore, those fatal cases showed a non-significant decline in the studied biochemical indices on follow up after 24 h, while the survivors showed a significant decline in the serum levels of IL-6, IL-1beta, NO and alpha1-AT after 24h of post arrival to the hospital. In conclusion, these data revealed that cytokines are involved in the pathogenesis of scorpion envenomation and correlated with the severity of envenomation. This may provide a rationale for anticytokine treatment.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号