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   105篇
  免费   12篇
  2023年   5篇
  2022年   10篇
  2021年   7篇
  2020年   5篇
  2019年   4篇
  2018年   9篇
  2017年   10篇
  2016年   4篇
  2015年   6篇
  2014年   8篇
  2013年   6篇
  2012年   11篇
  2011年   7篇
  2010年   6篇
  2009年   5篇
  2008年   3篇
  2007年   1篇
  2006年   1篇
  2005年   1篇
  2004年   3篇
  2003年   1篇
  2002年   2篇
  2001年   1篇
  2000年   1篇
排序方式: 共有117条查询结果,搜索用时 15 毫秒
101.
Cancer is the second most common cause of death globally, surpassed only by cardiovascular disease. One of the hallmarks of cancer is uncontrolled cell division and resistance to cell death. Multiple approaches have been developed to tackle this disease, including surgery, radiotherapy and chemotherapy. Although chemotherapy is used primarily to control cell division and induce cell death, some cancer cells are able to resist apoptosis and develop tolerance to these drugs. The side effects of chemotherapy are often overwhelming, and patients can experience more adverse effects than benefits. Furthermore, the bioavailability and stability of drugs used for chemotherapy are crucial issues that must be addressed, and there is therefore a high demand for a reliable delivery system that ensures fast and accurate targeting of treatment. In this review, we discuss the different types of nanocarriers, their properties and recent advances in formulations, with respect to relevant advantages and disadvantages of each.  相似文献   
102.
A new series of 1H-pyrrole (6a–c, 8a–c), pyrrolo[3,2-d]pyrimidines (9a–c) and pyrrolo[3,2-e][1, 4]diazepines (11a–c) were designed and synthesised. These compounds were designed to have the essential pharmacophoric features of EGFR Inhibitors, they have shown anticancer activities against HCT116, MCF-7 and Hep3B cancer cells with IC50 values ranging from 0.009 to 2.195 µM. IC50 value of doxorubicin is 0.008 µM, compounds 9a and 9c showed IC50 values of 0.011 and 0.009 µM respectively against HCT-116 cells. Compound 8b exerted broad-spectrum activity against all tested cell lines with an IC50 value less than 0.05 µM. Compound 8b was evaluated against a panel of kinases. This compound potently inhibited CDK2/Cyclin A1, DYRK3 and GSK3 alpha kinases with 10–23% compared to imatinib (1–10%). It has also arrested the cell cycle of MCF-7 cells at the S phase. Its antiproliferative activity was further augmented by molecular docking into the active sites of EGFR and CDK2 cyclin A1.  相似文献   
103.
A recent antineoplastic medication is pemetrexed, this medicine is now being developed and produced on a large scale, thus approaches for quality control are urgently needed. Spectrofluorimetric guidelines for the simple estimation of pemetrexed were validated. Pemetrexed's assay depends on observations of its native fluorescence at wavelengths 275/450 nm and pH 4. The proposed approach was also used to identify the examined drug in both its formulation and in human plasma that had been spiked.  相似文献   
104.
In view of their potential bioaccumulation of heavy metals, Ceratophyllum demersum and Myriophyllum spicatum was studied under hydroponic cultures enriched by different Pb concentrations (25, 50, 75 mg/l) for 1–7 days. Both species exerted remarkable capabilities to concentrate Pb in their tissues as compared to control. The highest accumulation value of Pb (164.26 mg/g.dw) was recorded in C. demersum and the most of metal (91.72 mg/g dw) accumulated after 1 d. Significant reduction in photosynthetic pigments and appearance of morphological symptoms such as chlorosis and fragmentation of leaves were evident after 7d at 75 mg/l. The activity of POX and APX, carotenoids and proline showed induction at lower concentration and duration followed by decline. Major re-shuffle in protein patterns appeared as a tolerant mechanism, which both species developed under Pb toxicity. Results suggest that both species responded positively to Pb concentration and accumulated high amount of metal. Due to metal accumulation coupled with detoxification potential, both species appear to have potential for use as phytoremediators and the developed responses can be used as reliable biomarkers for Pb water pollution.  相似文献   
105.
Cultures of a strain of Amphidinium carterae Hulburt isolated from a eutrophic basin in Alexandria were investigated for the optimum growth conditions, including vitamin requirements, the assimilation index and the potential toxicity of this species. A division rate of 2.7 day–1, was reached on the second and third day under optimum conditions, with and without addition of B12 and biotin. The rate of C14 assimilation per unit chlorophyll ranged from 0.2 to 5.4 mgC.(mg Chla)-1.h–1 according to the growth conditions and to cell size. As the cell density increased in the cultures, the cell size decreased and their photosynthetic efficiency increased. Toxicity of A. carterae to brine shrimp resulted from grazing and not from membrane diffusion of extracellular toxins.  相似文献   
106.
Russian Journal of Bioorganic Chemistry - Structure-based pharmacophore mapping, drug-likeness and ADMET profiles were used as tools in our virtual screening process, in addition to molecular...  相似文献   
107.
108.
BackgroundSchizophrenia is a serious, complex mental disorder. The impairment of oxidative phosphorylation has a detrimental consequence on CNS function. Different ATP synthase subunits have been involved in the pathological process of various neurodegenerative disorders. Our goal was to evaluate the mRNA expression level of the ATP synthase membrane subunit c locus 1 (ATP5G1, also named ATP5MC1) gene in patients with schizophrenia.MethodsDetermination of the expression levels of ATP5G1 in plasma and peripheral blood mononuclear cells (PBMCs) were performed by real-time PCR in 90 controls and 90 patients with schizophrenia.ResultsPatients had significantly decreased ATP5G1 mRNA expression levels in both plasma and PBMCs compared to controls. The receiver operating characteristic curve was applied to detect a cut-off value of ATP5G1 expression in plasma and PBMCs. The ATP5G1 relative expression in PBMCs had better performance with a cut-off value ≤ 21 (AUC = 0.892, P < 0.001), sensitivity of 94.44%, and specificity of 72.22% in discriminating between schizophrenic patients. ATP5G1 expression in PBMCs was an independent predictor in schizophrenia.ConclusionThis study revealed a down-regulation of ATP5G1 expression in schizophrenia, precisely expression in PBMCs. That might give insight into the role of ATP5G1 gene in the pathogenesis of schizophrenia.  相似文献   
109.
Melatonin  has been identified as a signal molecule that regulates plant responses to different abiotic and biotic stresses. Melatonin (MT) and its precursor tryptophan (Try) have a major role in improving plant stress tolerance to different environmental stresses such as water deficiency. The rapid increase in the Egyptian population caused insufficient protein sources, especially those of animal origin, in their diet. The possible solution is to augment the diet with legumes such as white lupine which are relatively rich in protein. Thus, the current experimental work was carried out to find changes in growth, biochemical aspects and yield quantity and quality of white lupine plant with spraying of both MT and Try at different concentrations on plant shoot under water deficit stress conditions. Results showed that water deficit (75 or 50% of water irrigation requirements; WIR) caused significant reduction in growth, photosynthetic pigments, indole acetic acid and yield compared with those received 100% WIR. Seed yield significantly decreased (p < 0.05) by 26.98 and 41.64% by decreasing WIR to 75 and 50%. The decrease was accompanied by significant increase in phenolic contents, hydrogen peroxide, lipid peroxidation and some antioxidant enzymes, while nitrate reductase enzyme was decreased. However, external application of either MT or Try significantly alleviated the adverse effects of water deficit (growth suppression), since MT or Try-treated plants recovered more quickly than untreated plants. Moreover, MT or Try—treated plants had higher photosynthetic pigments, indole acetic acid, phenolic, as well as yield quantity and quality under the three WIR as compared with untreated plants. Melatonin treatment at 100 µM and Tryptophan at 200 µM increased weight of seeds/plant by 78.29 and 52.19%, 71.49 and 43.78% and 41.21 and 13.07% in plants irrigated with 100, 75 and 50% WIR, respectively. Exogenous MT and Try significantly reduced hydrogen peroxide and malondialdehyde content, while markedly increased the activities of antioxidant enzymes and nitrate reductase under different WIR. Finally, the current study concluded that MT and Try treatments alleviated the detrimental effects of water deficiency and accelerated the recovery mainly via improving white lupine plants tolerance in forms of enhancing photosynthetic pigments, indole acetic acid, phenolic and antioxidant capacity.  相似文献   
110.

Background  

Constitutional delay of growth and puberty (CDGP) is a variation of the onset and timing of pubertal development without a defined endocrine abnormality. Recently published studies indicate that leptin and ghrelin play a role in puberty initiation and progress. They have been implicated in regulation of GnRH secretion, with ghrelin having inhibitory and leptin, facilitatory effects. We hypothesized that elevated ghrelin and reduced leptin concentrations could be implicated in altering the tempo of puberty in adolescents with CDGP. So in the current study we evaluate variations in leptin and ghrelin levels in adolescent boys with CDGP, the relationships between both hormones and reproductive hormones including LH, FSH and testosterone were also evaluated.  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