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   8篇
耳鼻咽喉   7篇
儿科学   7篇
妇产科学   2篇
基础医学   20篇
口腔科学   14篇
临床医学   16篇
内科学   32篇
皮肤病学   2篇
神经病学   18篇
特种医学   2篇
外科学   22篇
综合类   24篇
预防医学   15篇
眼科学   4篇
药学   8篇
肿瘤学   8篇
  2023年   2篇
  2022年   4篇
  2021年   20篇
  2020年   6篇
  2019年   8篇
  2018年   5篇
  2017年   8篇
  2016年   7篇
  2015年   7篇
  2014年   12篇
  2013年   12篇
  2012年   20篇
  2011年   13篇
  2010年   5篇
  2009年   1篇
  2008年   11篇
  2007年   2篇
  2006年   6篇
  2005年   10篇
  2004年   2篇
  2003年   6篇
  2002年   8篇
  2001年   1篇
  2000年   3篇
  1999年   4篇
  1998年   7篇
  1997年   2篇
  1993年   1篇
  1991年   3篇
  1987年   2篇
  1986年   2篇
  1979年   1篇
排序方式: 共有201条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
Polysaccharides isolated from mushrooms have recently attracted attention due to its potential immune-stimulatory activity. The aim of this study was to validate the in vitro immune-stimulatory activities of various mushroom extracts. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay revealed that Pleurotus eryngii, with the highest β-glucan (18.94%) content, displayed highest viability on macrophage cells of 62.59% at 200?μg/ml concentration. Pleurotus cystidiosus, with 18.16% β-glucan, content showed highest activation of NF-kB (0.7?µg/ml) at a concentration of 100?µg/ml. Termitomyces heimii, with the lowest percentage of β-glucan (0.51%), exhibited highest phagocytosis index of 9.38 at 12.5?µg/ml. The brown strain of Agaricus bisporus with 1.54% of β-glucan stimulates the highest nitric oxide (NO) production of 12.39?µM nitrite oxide at 100?µg/ml. This study revealed that hot water extracts of mushrooms have different β-glucan contents and produced varying immune-stimulatory activities. Among these, Pleurotus spp. demonstrated the highest percentage of β-glucan content and viability of macrophage cells. Pleurotus spp. are deemed immune-stimulatory by increasing phagocytic activity, NO production, and triggered the activation of NF-kB.  相似文献   
35.
Species of Phyllanthus have traditionally been used for hundreds of years for treating many ailments including diabetes, anemia, bronchitis and hepatitis. The present study aims to investigate the cytotoxic and apoptotic effects of methanol (PWM), hexane (PWH) and ethyl acetate (PWE) extracts from the leaves of the endemic plant Phyllanthus watsonii Airy Shaw (Phyllanthaceae) on MCF-7 human breast cancer cells. We observed that the PWM, PWH and PWE extracts were cytotoxic and selectively inhibited the growth and proliferation of MCF-7 cells compared to untreated control in a dose dependent manner with an IC50 of 12.7 ± 4.65, 7.9 ± 0.60 and 7.7 ± 0.29 μg/ml, respectively. However, the extracts were not toxic at these concentrations to normal human lung fibroblast MRC-5 cells. Cell death induced by PWM, PWH and PWE extracts were mainly due to apoptosis which was characterized by apoptotic morphological changes and a nuclear DNA fragmentation. Caspase-3 activation following P. watsonii extracts treatment was also evident for apoptotic cell death which was preceded by an S phase cell cycle perturbation. The results suggested that the cytotoxic activity of P. watsonii extracts was related to an early event of cell cycle perturbation and a later event of apoptosis. Hence, P. watsonii displays potential to be further exploited in the discovery and development of new anticancer agents.  相似文献   
36.
The intestinal permeability of mitragynine was investigated in situ using a single pass intestinal perfusion (SPIP) absorption model, in small intestine of rat using mitragynine in the absence/presence of the permeability markers, P-gp and/or CYP3A4 inhibitors. Mitragynine demonstrated high intestinal permeability (Peff of 1.11 × 10?4 cm/s) that is in the range of highly permeable drugs such as propranolol (Peff of 1.27 × 10?4 cm/s) indicating that it readily crosses the intestine. The addition of azithromycin (P-glycoprotein inhibitor) and ciprofloxacin (CYP3A4 inhibitor) or combination of both has no effect on intestinal permeability of mitragynine across the rat small intestine.  相似文献   
37.
Formation of the so-called organic-inorganic nanohybrid material was exploited for the preparation of a controlled release formulation. The inorganic Zn-Al-layered double hydroxide (LDH) was used as a matrix, hosting an active agent or a guest, alpha-naphthaleneacetate (NAA), a plant growth regulator by self-assembly technique. The reverse process, i.e., the deintercalation or release of the guest, NAA was found to be rapid initially, followed by a more sustained release thereafter and this behavior was dependent on the pH of the release medium, the aqueous solution. The mechanism of release has been interpreted on the basis of the ion-exchange process between the NAA anion intercalated in the lamella host and nitrate or hydroxyl anions in the aqueous solution.  相似文献   
38.
Chest wall resection is defined as partial or full-thickness removal of the chest wall. Significant morbidity has been recorded, with documented respiratory failure as high as 27%. Medical records of all patients who had undergone chest wall resection and reconstruction were reviewed. Patients’ demographics, length of surgery, reconstruction method, size of tumor and chest wall defect, histopathological result, complications, duration of post-operative antibiotics, and hospital stay were assessed. From 1 April 2017 to 30 April 2019, a total of 20 patients underwent chest wall reconstructive surgery. The median age was 57 years, with 12 females and 8 males. Fourteen patients (70%) had malignant disease and 6 patients (30%) had benign disease. Nine patients underwent rigid reconstruction (titanium mesh for sternum and titanium plates for ribs), 6 patients had non-rigid reconstruction (with polypropylene or composite mesh), and 5 patients had primary closure. Nine patients (45%) required closure with myocutaneous flap. Complications were noted in 70% of patients. Patients who underwent primary closure had minor complications. In total, 66.7% of patients who had closure with either fasciocutaneous or myocutaneous flaps had threatened flap necrosis. Two patients developed pneumonia and 3 patients (15%) had respiratory failure requiring tracheostomy and prolonged ventilation. There was 1 mortality (5%) in this series. In conclusion, chest wall resections involving large defects require prudent clinical judgment and multidisciplinary assessments in determining the choice of chest wall reconstruction to improve outcomes.  相似文献   
39.
Recycling of the waste rubber tire crumbs (WRTCs) for the concretes production generated renewed interest worldwide. The insertion of such waste as a substitute for the natural aggregates in the concretes is an emergent trend for sustainable development towards building materials. Meanwhile, the enhanced resistance of the concrete structures against aggressive environments is important for durability, cost-saving, and sustainability. In this view, this research evaluated the performance of several modified rubberized concretes by exposing them to aggressive environments i.e., acid, and sulphate attacks, elevated temperatures. These concrete (12 batches) were made by replacing the cement and natural aggregate with an appropriate amount of the granulated blast furnace slag (GBFS) and WRTCs, respectively. The proposed mix designs’ performance was evaluated by several measures, including the residual compressive strength (CS), weight loss, ultrasonic pulse velocity (UPV), microstructures, etc. Besides, by using the available experimental test database, an optimized artificial neural network (ANN) combined with the particle swarm optimization (PSO) was developed to estimate the residual CS of modified rubberized concrete after immersion one year in MgSO4 and H2SO4 solutions. The results indicated that modified rubberized concrete prepared by 5 to 20% WRTCs as a substitute to natural aggregate, provided lower CS and weight lose expose to sulphate and acid attacks compared to control specimen prepared by ordinary Portland cement (OPC). Although the CS were slightly declined at the elevated temperature, these proposed mix designs have a high potential for a wide variety of concrete industrial applications, especially in acid and sulphate risk.  相似文献   
40.
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