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   343篇
  免费   26篇
耳鼻咽喉   10篇
儿科学   32篇
妇产科学   12篇
基础医学   55篇
口腔科学   9篇
临床医学   26篇
内科学   48篇
皮肤病学   1篇
神经病学   43篇
特种医学   7篇
外科学   68篇
综合类   4篇
预防医学   10篇
眼科学   10篇
药学   14篇
中国医学   2篇
肿瘤学   18篇
  2023年   3篇
  2022年   7篇
  2021年   12篇
  2020年   2篇
  2019年   7篇
  2018年   11篇
  2017年   8篇
  2016年   14篇
  2015年   16篇
  2014年   22篇
  2013年   33篇
  2012年   48篇
  2011年   34篇
  2010年   5篇
  2009年   10篇
  2008年   19篇
  2007年   19篇
  2006年   24篇
  2005年   17篇
  2004年   15篇
  2003年   7篇
  2002年   4篇
  2001年   7篇
  2000年   5篇
  1999年   3篇
  1998年   2篇
  1997年   1篇
  1996年   4篇
  1995年   1篇
  1994年   1篇
  1993年   1篇
  1992年   2篇
  1991年   2篇
  1986年   1篇
  1984年   1篇
  1981年   1篇
排序方式: 共有369条查询结果,搜索用时 343 毫秒
1.
Percutaneous nephrolithotomy in older children   总被引:4,自引:0,他引:4  
PURPOSE: The aim of this study was to evaluate the safety and efficacy of percutaneous nephrolithotomy (PCNL) in pediatric patients, older than 8 years, without any technical and instrumental modifications. METHODS: The authors retrospectively evaluated the data of 16 percutaneously treated kidneys of 14 patients with a mean age of 11 years (range, 8 to 17). The mean stone burden was calculated as 301 mm2 (range, 120-750). Percutaneous accesses were done under fluoroscopic control, and 24F to 30F Amplatz dilators were used depending on patient size. Ultrasonic and laser lithotripsy were performed to fragment calculi. RESULTS: Mean operating time was 111 minutes (range, 60 to 210 min) and no intraoperative or postoperative major complication was observed. Mean hemoglobin drop after the procedure was 1.16 g/dL (range, 0.3 to 2.8). Blood transfusion was required in only 1 patient, and mean postoperative hospitalization was 4.6 days (range, 3 to 10). Stone-free rate was calculated as 69% (11 of 16), but with residual fragments smaller than 4 mm, the success rate becomes 100% at patient's discharge. CONCLUSIONS: PCNL is an effective and safe form of therapy in pediatric stone disease. Especially in older children the use of the same instruments and technique as in adults may achieve equal results without any increased risk of possible morbidity and need of blood transfusion.  相似文献   
2.
Endometrial carcinoma (EnCa) is the most common invasive gynaecologic carcinoma. Over 85% of EnCa are classified as endometrioid, expressing steroid hormone receptors and mostly involving pathological prestages. Human endogenous retroviruses (ERV) are chromosomally integrated genes, account for about 8% of the human genome and are implicated in the etiology of carcinomas. The majority of ERV envelope (env) coding genes are either not present or not consistently represented between common gene expression microarrays. The aim of this study was to analyse the absolute gene expression of all known 21 ERV env genes including 19 codogenic and two env genes with premature stop codons in EnCa, endometrium as well as in hyperplasia and polyps. For EnCa seven env genes had high expression with >200 mol/ng cDNA (e.g. envH1-3, Syncytin-1, envT), two middle >50 mol/ng cDNA (envFc2, erv-3) and 12 low <50 mol/ng cDNA (e.g. Syncytin-2, envV2). Regarding tumor parameters, Syncytin-1 and Syncytin-2 were significantly over-expressed in advanced stage pT2 compared to pT1b. In less differentiated EnCa Syncytin-1, erv-3, envT and envFc2 were significantly over-expressed. Syncytin-1, Syncytin-2 and erv-3 were specific to glandular epithelial cells of polyps, hyperplasia and EnCa using immunohistochemistry. An analysis of 10 patient-matched EnCa with endometrium revealed that the ERV-W 5'' long terminal repeat regulating Syncytin-1 was hypomethylated, including the ERE and CRE overlapping MeCP2 sites. Functional analyses showed that 10 env genes were regulated by methylation in EnCa using the RL95-2 cell line. In conclusion, over-expressed env genes could serve as indicators for pathological pre-stages and EnCa.  相似文献   
3.
Myocardial infarction and systemic arterial aneurysms are rarely seen during the course of the Kawasaki disease (KD). Herein, we report the case of a 4‐month‐old Turkish infant who was diagnosed with KD on the 17th day of the illness. On admission, echocardiogram showed multiple coronary arterial aneurysms (CAAs) and massive pericardial effusion. He was given intravenous immunoglobulin, aspirin and anticoagulant drugs. However, the aneurysms progressed to “super giant” CAAs, multiple huge coronary arterial thromboses developed recurrently and caused myocardial ischemia. Furthermore, the conventional angiography revealed multiple giant aneurysms and stenoses in the subclavian, celiac, and iliac arteries, besides CAAs.  相似文献   
4.
5.

Purpose

The gallbladder and the biliary tract are structures in close connection with the adjacent organs and may show a number of variations and anomalies. It is therefore important for surgical purposes to know their anatomy and variations in detail. Various methods are used in the imaging of the variations of the biliary tract and its pathologies, including ultrasonography, computed tomography; direct cholangiographic methods like endoscopic retrograde cholangiopancreatography, percutaneous transhepatic cholangiography, intravenous cholangiography and T-tube cholangiography, as well as indirect methods like magnetic resonance cholangiopancreatography (MRCP) or cholescintigraphy. The aim of this study is to investigate the frequency of the anatomic variations of the biliary tract using 3-T MRCP and to compare the findings with the data in the literature.

Materials and methods

For the purposes of this study, patients who underwent MRCP at our hospital (Dicle University Hospital) between November 2009 and February 2012 were investigated retrospectively. A total of 590 patients (between 6 and 88 years of age; mean age: 51 ± 9 years) were included in the study. The MRCP imaging was carried out with an magnetic resonance imaging (MRI) device supplied with 3-T magnetic power and by obtaining T2-weighted images through the single-shot fast spin echo technique using the standard body coil. The axial and coronal source images and the reformatted images were evaluated together in terms of the possible anatomic variations.

Results

Among the 590 patients included in the study, of 233 (39.5 %) showed anatomic variations at different levels in the intra- and extrahepatic biliary tracts. Among these variations, a right posterior hepatic duct insertion to the left hepatic duct at the level of the bifurcation has been observed in 71 patients (12.1 %), trifurcation was observed in 30 patients (5.1 %) and insertion into the main hepatic duct at the proximal aspect of the cystic duct was observed in 18 patients (3.1 %). At the level of the cystic duct, medial insertion of the cystic duct was viewed in 58 patients (9.8 %), distal medial insertion was seen in 40 patients (6.8 %), a short cystic duct was detected in 10 patients (1.7 %), pancreatobiliary junction anomaly was viewed in two patients (0.4 %) and duplicate anatomic variations have been observed in 42 patients (7.2 %).

Conclusion

MRCP studies conducted using 3-T MRI devices may reveal similar or greater numbers of variations when compared to the existing MRCP studies in the literature. 3-T MRI shows a couple of variations. Pointing out these anatomical variations before the surgical intervention may prevent possible iatrogenic traumas. Donors with unsuitable variations for liver transplant may be spotted out at an early phase through the MRCP and certain operations with a high morbidity rate may thus be avoided.  相似文献   
6.
Oxidative stress is considered to play a key role in ageing. Carnosine alone or together with vitamin E may prove to be helpful in dealing with problems of ageing through its antioxidant activity. Testis, by producing steroids and possessing a poor antioxidant system may become a strong target for the chronic oxidative stress generated during ageing. Therefore we investigated the in vivo effect of carnosine alone or together with vitamin E on testicular oxidative stress in aged rats. In this study, young (5 months) and aged (22 months) Wistar rats were used. Carnosine (250 mg kg?1; i.p.; 5 days per week) and vitamin E (200 mg kg?1; i.m.; twice per week) were given to aged rats for 2 months. Increased testicular lipid peroxidation and superoxide dismutase activity in aged rats were declined to the levels of young ones by both treatments. Decreased glutathione peroxidase and glutathione transferase activities returned to the level of young's only by carnosine plus vitamin E treatment. Histopathological evaluation described by Johnsen's score, also showed significant improvement with preserved spermatogenesis. Carnosine plus vitamin E treatment appears to stage a powerful performance by attenuating testicular oxidative stress and sparing the antioxidant system.  相似文献   
7.
8.
9.
10.
Due to the high demand for donor corneas and their low supply, autologous corneal endothelial cell (CEC) culture and transplantation for treatment of corneal endothelial dysfunction would be highly desirable. Many studies have shown the possibility of culturing CECs in vitro, but lack potential robust substrates for transplantation into the cornea. In this study, we investigate the properties of novel ultrathin chitosan–poly(ethylene glycol) (PEG) hydrogel films (CPHFs) for corneal tissue engineering applications. Cross-linking of chitosan films with diepoxy-PEG and cystamine was employed to prepare 50 μm (hydrated) hydrogel films. Through variation of the PEG content (1.5–5.9 wt.%) it was possible to tailor the CPHFs to have tensile strains and ultimate stresses identical to or greater than those of human corneal tissue while retaining similar tensile moduli. Light transmission measurements in the visible spectrum (400–700 nm) revealed that the films were >95% optically transparent, above that of the human cornea (maximum ~90%), whilst in vitro degradation studies with lysozyme revealed that the CPHFs maintained the biodegradable characteristics of chitosan. Cell culture studies demonstrated the ability of the CPHFs to support the attachment and proliferation of sheep CECs. Ex vivo surgical trials on ovine eyes demonstrated that the CPHFs displayed excellent characteristics for physical manipulation and implantation purposes. The ultrathin CPHFs display desirable mechanical, optical and degradation properties whilst allowing attachment and proliferation of ovine CECs, and as such are attractive candidates for the regeneration and transplantation of CECs, as well as other corneal tissue engineering applications.  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