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   432篇
  免费   31篇
  国内免费   4篇
耳鼻咽喉   4篇
儿科学   16篇
妇产科学   18篇
基础医学   57篇
口腔科学   12篇
临床医学   34篇
内科学   102篇
皮肤病学   20篇
神经病学   10篇
特种医学   32篇
外科学   47篇
综合类   3篇
现状与发展   1篇
预防医学   21篇
眼科学   20篇
药学   44篇
中国医学   2篇
肿瘤学   24篇
  2023年   7篇
  2022年   23篇
  2021年   42篇
  2020年   27篇
  2019年   39篇
  2018年   38篇
  2017年   25篇
  2016年   25篇
  2015年   27篇
  2014年   18篇
  2013年   33篇
  2012年   36篇
  2011年   36篇
  2010年   20篇
  2009年   13篇
  2008年   14篇
  2007年   7篇
  2006年   15篇
  2005年   5篇
  2004年   3篇
  2003年   5篇
  2002年   3篇
  1997年   1篇
  1986年   1篇
  1984年   2篇
  1981年   1篇
  1974年   1篇
排序方式: 共有467条查询结果,搜索用时 31 毫秒
1.
Despite the importance of short-chain fatty acids (SCFA) in maintaining the ruminant physiology, the mechanism of SCFA absorption is still not fully studied. The goal of this study was to elucidate the possible involvement of monocarboxylate transporter 1 (MCT1) in the mechanism of SCFA transport in the caprine rumen, and to delineate the precise cellular localization and the level of MCT1 protein along the entire caprine gastrointestinal tract. RT-PCR revealed the presence of mRNA encoding for MCT1 in all regions of the caprine gastrointestinal tract. Quantitative Western blot analysis showed that the level of MCT1 protein was in the order of rumen ≥ reticulum > omasum > caecum > proximal colon > distal colon > abomasum > small intestine. Immunohistochemistry and immunofluorescence confocal analyses revealed widespread immunoreactive positivities for MCT1 in the caprine stomach and large intestine. Amongst the stratified squamous epithelial cells of the forestomach, MCT1 was predominantly expressed on the cell boundaries of the stratum basale and stratum spinosum. Double-immunofluorescence confocal laser-scanning microscopy confirmed the co-localization of MCT1 with its ancillary protein, CD147 in the caprine gastrointestinal tract. In vivo and in vitro functional studies, under the influence of the MCT1 inhibitors, p -chloromercuribenzoate (pCMB) and p -chloromercuribenzoic acid (pCMBA), demonstrated significant inhibitory effect on acetate and propionate transport in the rumen. This study provides evidence, for the first time in ruminants, that MCT1 has a direct role in the transepithelial transport and efflux of the SCFA across the stratum spinosum and stratum basale of the forestomach toward the blood side.  相似文献   
2.
Background:Randomizing patients to bladder preservation or radical cystectomy (RC) for the treatment of bladder cancer has not been practical, due to patient and physician preferences. Therefore, continually comparing the 2 treatment modalities is needed, in order to make the proper choice for each patient.Patients and methods:The records of T1–4N0M0 bladder cancer patients, who presented to the South Egypt Cancer Institute between 2007 and 2017 and were treated by either bladder preservation or RC were reviewed.Results:Out of the 166 included patients, 81 (48.8%) patients were treated by bladder preservation and 85 (51.2%) patients had RC. For the patients treated by bladder preservation and the patients treated by RC, the 5-year overall survival (OS) was 56% and 60% (p = 0.67), the 5-year local recurrence-free survival was 69% and 73% (p = 0.69), and the 5-year disease-free survival was 45% and 53% (p = 0.16), respectively. After propensity matching analysis, the mean 5-year OS was 58% for the bladder preservation patients and 61% for the RC patients (p = 0.51). It is notable that among the bladder preservation group, 8 patients (10%) had squamous cell carcinoma (SCC) pathology and refused RC. Their OS was 56% compared to 53% for the SCC patients treated by RC (p = 0.6).Conclusion:Bladder preservation is a safe alternative to cystectomy in transitional cell carcinoma stages T1–4aN0M0, and its use in SCC bladder cancer should be further studied, as it could be feasible to spare them from initial cystectomy.  相似文献   
3.
The efficacy of transfersomes (flexible liposomes) as a novel technique for topical delivery of the hydrophilic tetra-anionic photodynamic sensitizer aluminum (III) phthalocyanine tetrasulfonate (AlPcS4) was investigated, on mammalian fibroblasts and on Balb/c mice dorsal skin. AlPcS4 was loaded in transfersomes composed of phosphatidylcholine/sodium deoxycholate (5:1, 10:1, and 15:1?w/w, ratios), resulting in 110-, 160-, and 200-nm mean size vesicles with encapsulation efficiencies of 16, 25, and 30 %, respectively. In vitro studies on baby hamster kidney-21 fibroblasts revealed twofold enhancement of the photocytotoxicity of AlPcS4 loaded in transfersomes (Trans-AlPcS4), compared to free AlPcS4 dissolved in culture medium. The photocytotoxicity of Trans-AlPcS4 was less dependent on the incubation time with cells, compared to free AlPcS4. Topical application on the dorsal skin of Balb/c mice revealed that both free AlPcS4 and Trans-AlPcS4 exhibited evident photosensitization towards mice skin, but acquiring different regions of skin.  相似文献   
4.
Despite widespread use of bromuconazole as a pesticide for food crops and fruits, limited studies have been done to evaluate its toxic effects. Here, we evaluated the hepatotoxic effect of bromuconazole using classical toxicological (biochemical analysis and histopathological examination) and gene-based molecular methods. Male rats were treated either orally or topically with bromuconazole at doses equal to no observed adverse effect level (NOAEL) and 1/10 LD50 for 90?d. Bromuconazole increased activities of liver enzymes (ALT, AST, ALP, and ACP), and levels of bilirubin. It also induced hepatic oxidative stress as evidenced by significant decrease in the activities of superoxide dismutase (SOD), and significant increase in levels of malondialdehyde (MDA) in liver. In addition, bromuconazole caused an increase in liver weights and necrobiotic changes (vacuolation and hepatocellular hypertrophy). It also strongly induced the expression of PXR and its downstream target CYP3A1 gene as well as the activity of CYP3A1. However, it inhibited the expression of CAR and its downstream target CYP2B1 gene without significant changing in CYP2B1 activity. Overall, the oral route showed higher hepatotoxic effect and molecular changes than the dermal route and all changes were dose dependent. This is the first investigation to report that bromuconazole-induced liver oxidative damage is accompanied by upregulation of PXR/CYP3A1 and downregulation of CAR/CYP2B1.  相似文献   
5.
6.
Journal of Assisted Reproduction and Genetics - Ferroptosis is associated with oxidative stress (OS) and is caused by iron-dependent lipid-peroxidative damage, but its role in PE is unclear. The...  相似文献   
7.
8.
Diabetic nephropathy is a clinical syndrome characterized by albuminuria, hypertension and progressive renal insufficiency. The aim of this study was to investigate the effect of strawberry (Fragaria × ananassa) leaf extract on diabetic nephropathy in rats. Streptozotocin (STZ) diabetic rats were orally treated with three doses (50, 100 and 200 mg/kg) of strawberry leaf extract for 30 days. Nephropathy biomarkers in plasma and kidney were examined at the end of the experiment. The three doses of strawberry leaf extract significantly decreased the levels of blood glucose, urea nitrogen, plasma creatinine, kidney injury molecule (Kim)‐1, renal malondialdehyde (MDA), tumour necrosis factor alpha (TNF‐α), interleukin (IL)‐ 6 and caspase‐3 in diabetic rats. Meanwhile, the levels of plasma insulin, albumin, uric acid, renal catalase (CAT), superoxide dismutase (SOD) and vascular endothelial growth factor A (VEGF‐A) were significantly elevated in diabetic rats treated with strawberry leaf extract. These results indicate the role of strawberry leaves extract as anti‐diabetic, antioxidant, anti‐inflammatory and anti‐apoptosis in diabetic nephropathy.  相似文献   
9.
10.
A central venous catheter is the most common access for initiating hemodialysis. Prolonged access through a central venous catheter increases the risk of infection and dysfunction of the catheter with potential development of catheter-induced thrombosis and embolism. However, fracture and dislodgement of the catheter with subsequent embolization is an unexpected complication. Endovascular treatment is a promising method to remove intravascular foreign bodies. We herein report a case of a 58-year-old woman undergoing prolonged hemodialysis who required central venous catheter removal because of mechanical fracture of the tunneled cuffed catheter and its migration in the internal jugular vein. An urgent chest X-ray showed that the two free ends of the fractured tunneled cuffed catheter were located in the right atrium and right internal jugular vein. Phlebotomy of the internal jugular vein was successfully performed to retrieve the fractured tunneled cuffed catheter and the associated thrombi. In this case, phlebotomy for retrieval of the embolized catheter fragment extending into the right atrium was a safe alternative to an endovascular technique of catheter fragment retrieval. Phlebotomy preserved the integrity of the catheter fragment and its associated thrombus and was both cost-effective and safe.  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