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   1817篇
  免费   117篇
  国内免费   14篇
耳鼻咽喉   73篇
儿科学   55篇
妇产科学   70篇
基础医学   177篇
口腔科学   63篇
临床医学   168篇
内科学   308篇
皮肤病学   32篇
神经病学   106篇
特种医学   62篇
外科学   257篇
综合类   44篇
预防医学   139篇
眼科学   65篇
药学   192篇
中国医学   40篇
肿瘤学   97篇
  2024年   4篇
  2023年   29篇
  2022年   78篇
  2021年   98篇
  2020年   73篇
  2019年   87篇
  2018年   94篇
  2017年   79篇
  2016年   66篇
  2015年   70篇
  2014年   89篇
  2013年   97篇
  2012年   146篇
  2011年   123篇
  2010年   71篇
  2009年   58篇
  2008年   113篇
  2007年   73篇
  2006年   84篇
  2005年   60篇
  2004年   46篇
  2003年   48篇
  2002年   45篇
  2001年   28篇
  2000年   20篇
  1999年   22篇
  1998年   13篇
  1997年   9篇
  1996年   6篇
  1995年   5篇
  1994年   4篇
  1992年   9篇
  1991年   5篇
  1990年   15篇
  1989年   10篇
  1988年   11篇
  1987年   10篇
  1986年   6篇
  1985年   8篇
  1984年   8篇
  1983年   3篇
  1982年   3篇
  1981年   5篇
  1978年   3篇
  1977年   4篇
  1976年   2篇
  1975年   3篇
  1973年   1篇
  1969年   2篇
  1928年   1篇
排序方式: 共有1948条查询结果,搜索用时 15 毫秒
41.
Uterine lymphoma is rare and tends to be misdiagnosed due to lack of specific radiologic features. Few reports have been published on the sonographic characteristics of uterine lymphoma. We present a case report of uterine lymphoma manifested by a fast growing uterus and describe the sonographic findings. © 2014 Wiley Periodicals, Inc. J Clin Ultrasound, 43 :59–63, 2015  相似文献   
42.
BACKGROUND: Recurrent abdominal pain (RAP) affects many children, especially those affected by beta-thalassaemia major. The role of Helicobacter pylori is still unclear in children with RAP. OBJECTIVES: The aim of the present study was the comparison of beta-thalassaemia major patients and normal controls with RAP in H. pylori infection. The factors influencing H. pylori prevalence were also investigated. METHODS: A series of 50 beta-thalassaemia major cases (30 female, 20 male; aged 6-25 years) and 50 age-matched and sex-matched controls, both presenting with RAP, were recruited during a period of 18 months. The study participants were obtained through a multistage random sampling method among those that met Apley's criteria. All the patients and controls had undergone diagnostic oesophagogastroduodenoscopy with biopsy. H. pylori infection was confirmed by two histopathological examinations on an endoscopy sample and a rapid urease test. RESULTS: H. pylori infection in thalassaemic patients was more common than in controls [34/50 (68%) versus 30/50 (60%)], but this higher frequency was not statistically significant. A clear relationship was found between the prevalence of H. pylori and age, duration of transfusion/chelation programmes, pain duration and splenectomy. In contrast, H. pylori did not correlate with abdominal pain characteristics, blood group, serum ferritin level and pathology of the upper gastrointestinal tract. The most frequent endoscopy abnormality was gastritis (72%). Nausea and heartburn were the leading associated symptoms. CONCLUSION: The high prevalence of H. pylori infection suggests that H. pylori should be remembered as a probable cause of RAP in beta-thalassaemia major patients.  相似文献   
43.
44.
45.
Acetaminophen (APAP) is the most commonly reported toxic ingestion in the world. Severe liver injury resulting from overdose or chronic use of APAP remains a significant clinical problem. In recent years, the mechanisms underlying liver injury caused by APAP have become much better understood. We have studied the protective effect of chitosan supplementation against APAP-induced hepatotoxicity with respect to changes in the levels of total and lipid-bound sialic acid in the serum and in the liver tissue and changes in the activity of diagnostic marker enzymes, lipid peroxidation, and ceruloplasmin oxidase enzyme in normal and experimental groups of rats. During the experimental period, chitosan (200 mg/kg body weight per day) was administered to APAP + chitosan-treated rats by oral gavage. Results showed that treatment with APAP induced a significant increase in the serum alanine aminotransferase and alkaline phosphatase activities, in total and lipid-bound sialic acids levels, and in the liver lipid peroxide content. The administration of chitosan significantly prevented APAP-induced alterations in the levels of diagnostic marker enzymes, total sialic acid, lipid-bound sialic acid, and malondialdehyde in the experimental groups of rats. Furthermore, chitosan administration increased the activity of ceruloplasmin oxidase. In conclusion, our results suggest that chitosan has a protective effect on APAP-induced hepatic injury in rats. The study sheds light on the therapeutic potential of chitosan in an APAP-induced hepatotoxicity model.  相似文献   
46.
47.
This study compared the push‐out bond strength of mineral trioxide aggregate (MTA) and a new endodontic cement (NEC) as root‐end filling materials in root‐end cavities prepared by ultrasonic technique (US) or Er,Cr:YSGG laser (L). Eighty single‐rooted extracted human teeth were endodontically treated, apicectomised and randomly divided into four following groups (n = 20): US/MTA, US/NEC, L/MTA and L/NEC. In US/MTA and US/NEC groups, root‐end cavities were prepared with ultrasonic retrotip and filled with MTA and NEC, respectively. In L/MTA and L/NEC groups, root‐end cavities were prepared using Er,Cr:YSGG laser and filled with MTA and NEC, respectively. Each root was cut apically to create a 2 mm‐thick root slice for measurement of bond strength using a universal testing machine. Then, all slices were examined to determine the mode of bond failure. Data were analysed using two‐way anova . Root‐end filling materials showed significantly higher bond strength in root‐end cavities prepared using ultrasonic technique (US/MTA and US/NEC) (P < 0.001). The bond strengths of MTA and NEC did not differ significantly. The failure modes were mainly adhesive for MTA, but cohesive for NEC. In conclusion, bond strengths of MTA and NEC to root‐end cavities were comparable and higher in ultrasonically prepared cavities.  相似文献   
48.
49.
50.
In inoperable or high-risk patients with severe aortic stenosis, transcatheter aortic valve implantation (TAVI) provides an efficacious and safe alternative to surgical aortic valve replacement. In this case report, TAVI resulted in aortic valve cusp shearing and migration into the left main coronary artery, resulting in occlusion of coronary blood flow and cardiac arrest. The patient underwent immediate cardiopulmonary support and surgical intervention with a favourable outcome. With this case report, we illustrate the etiology and management of this complication, which can be recognized nonsurgically only if a high index of suspicion exists.  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