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   449篇
  免费   89篇
耳鼻咽喉   1篇
儿科学   10篇
妇产科学   4篇
基础医学   77篇
口腔科学   8篇
临床医学   60篇
内科学   267篇
皮肤病学   8篇
神经病学   22篇
特种医学   4篇
外科学   27篇
综合类   10篇
预防医学   6篇
眼科学   9篇
药学   7篇
中国医学   1篇
肿瘤学   17篇
  2022年   6篇
  2021年   4篇
  2020年   2篇
  2019年   7篇
  2018年   11篇
  2017年   2篇
  2016年   3篇
  2015年   6篇
  2014年   15篇
  2013年   11篇
  2012年   15篇
  2011年   17篇
  2010年   11篇
  2009年   7篇
  2008年   22篇
  2007年   19篇
  2006年   16篇
  2005年   19篇
  2004年   14篇
  2003年   22篇
  2002年   17篇
  2001年   15篇
  2000年   13篇
  1999年   15篇
  1998年   5篇
  1997年   8篇
  1996年   5篇
  1995年   8篇
  1994年   4篇
  1993年   7篇
  1992年   31篇
  1991年   22篇
  1990年   15篇
  1989年   9篇
  1988年   11篇
  1987年   13篇
  1986年   21篇
  1985年   12篇
  1984年   18篇
  1983年   8篇
  1982年   5篇
  1981年   6篇
  1980年   12篇
  1979年   3篇
  1978年   6篇
  1977年   5篇
  1975年   3篇
  1973年   3篇
  1972年   2篇
  1971年   3篇
排序方式: 共有538条查询结果,搜索用时 15 毫秒
91.
Of the 312 cases of esophageal cancer seen over 2 years, four patients had associated varices. Three patients gave history of alcohol abuse. All had malnutrition and splenomegaly. Endoscopic biopsies were safe in the presence of varices. External radiation did not have any untoward effect on the varices. Prophylactic sclerotherapy was not required in these patients. The association between esophageal carcinoma and varices could be secondary to alcohol consumption or merely coincidental.  相似文献   
92.
Hereditary ovalocytosis in Malays   总被引:1,自引:0,他引:1  
  相似文献   
93.
Protein 4.1 is an approximately 80-kD structural protein in the membrane skeleton which underlies and supports the erythrocyte plasma membrane. The preceding companion paper presents a biochemical study of two abnormal protein 4.1 species from individuals with the red blood cell disorder, hereditary elliptocytosis. These variants, "protein 4.1(68/65)" and "protein 4.1(95)," have altered molecular weights due to internal deletions and duplications apparently localized around the spectrin-actin binding domain. Here we use polymerase chain reaction (PCR) techniques to clone and sequence the corresponding mutant reticulocyte mRNAs, and correlate the deletion/duplication end points with exon boundaries of the gene. Protein 4.1(68/65) mRNA lacks sequences encoding the functionally important spectrin-actin binding domain due to a 240 nucleotide (nt) deletion spanning the codons for Lys407-Gly486. Protein 4.1(95) mRNA encodes a protein with two spectrin-actin binding domains by virtue of a 369 nt duplication of codons for Lys407-Gln529. These deletions and duplications correspond to gene rearrangements involving three exons encoding 21, 59, and 43 amino acids, respectively. The duplicated 21 amino acid exon in the 4.1(95) gene retains its proper tissue-specific expression pattern, being spliced into reticulocyte 4.1 mRNA and out of lymphocyte 4.1 mRNA.  相似文献   
94.
Aim: The aim of this study is to report a retrospective case series on orbital infantile haemangiomas (OIH). Radiological features and treatment with oral propranolol (OP) are illustrated along with an updated literature review. Methods: A retrospective chart review of six children, diagnosed with OIH from November 2015 to October 2016, was carried out. Only children with deep documented orbital involvement were included. All patients underwent magnetic resonance imaging (MRI) under general anaesthesia. OP was administered to the infants according to the Nottingham Children's Hospital guideline. As per the guideline, a preliminary paediatric assessment was performed and a 1 mg/kg test dose was administered, followed by definitive treatment at a dosage of 2 mg/kg in three divided doses.Results: Average age at presentation was within the first 3 weeks of life. T1 hypointensity, T2 hyperintensity, avid enhancement with contrast, and the presence of flow-voids appear a fixed pattern of OIH on MRI. Response to treatment was noticed within 4 weeks in all children, and two of them (33.3%) responded within the first 7 days. In two children (33.3%), the haemangioma became clinically undetectable by the seventh month of treatment, while the other four (66.6%) experienced an almost complete regression of the OIH by the last follow-up. No complications were found.Conclusions: Our series strengthens the understanding that MRI is the preferred imaging modality in the investigation of OIH, showing vascular features, detailed orbital extension, and possible associated malformations. OP is the treatment of choice for OIH, and our study confirms its safety and effectiveness.  相似文献   
95.
96.
97.
98.
99.

Background

Tranexamic acid reduces blood loss and transfusion requirements in cardiac surgery but may increase the risk of coronary graft thrombosis. We previously reported the 30-day results of a trial evaluating tranexamic acid for coronary artery surgery. Here we report the 1-year clinical outcomes.

Methods

Using a factorial design, we randomly assigned patients undergoing coronary artery surgery to receive aspirin or placebo and tranexamic acid or placebo. The results of the tranexamic acid comparison are reported here. The primary 1-year outcome was death or severe disability, the latter defined as living with a modified Katz activities of daily living score of less than 8. Secondary outcomes included a composite of myocardial infarction, stroke, and death from any cause through to 1 year after surgery.

Results

The rate of death or disability at 1 year was 3.8% in the tranexamic acid group and 4.4% in the placebo group (relative risk, 0.85; 95% confidence interval, 0.64-1.13; P = .27), and this did not significantly differ according to aspirin exposure at the time of surgery (interaction P = .073). The composite rate of myocardial infarction, stroke, and death up to 1 year after surgery was 14.3% in the tranexamic acid group and 16.4% in the placebo group (relative risk, 0.87; 95% CI, 0.76-1.00; P = .053).

Conclusions

In this trial of patients having coronary artery surgery, tranexamic acid did not affect death or severe disability through to 1 year after surgery. Further work should be done to explore possible beneficial effects on late cardiovascular events.  相似文献   
100.
The large bowel is a leading site for cancers in developed countries whereas small bowel cancers are rare worldwide. The incidence rates of both large and small bowel cancer are low in India, and rectal cancer is more common than colon cancer. The incidence rates of colon cancer in eight population registries vary from 3.7 to 0.7/100,000 among men and 3 to 0.4/100,000 among women. For rectal cancer the incidence rates range from 5.5 to 1.6/100,000 among men and 2.8 to 0/100,000 among women. One intriguing observation is the occurrence of rectal cancer in young Indians. Rural incidence rates for large bowel cancers in India are approximately half of urban rates. Based on data from eight registries, we estimate that, in the year 2001, the incidence of large bowel cancer in India will be 18,427 in men and 13,092 in women. Immigrant studies reveal an increase in incidence as compared to the rates in native counterparts. Reliable time trends for India are available only from the Bombay registry. Significant increase in the incidence of colon cancer has been reported for both men and women over two decades, but the rates of rectal cancer are steady. The low incidence of large bowel cancers in Indians can be attributed to high intake of starch and the presence of natural antioxidants such as curcumin in Indian cooking. The role of hereditary factors has been evaluated in a few studies. Some studies have reported the occurrence of both FAP and HNPCC in India. There are no Indian studies on large bowel cancer prevention. The prevalence of adenomas is rare in elderly Indians undergoing colonoscopy, even in those with large bowel cancers. Small bowel cancers are extremely rare in India and no analytical studies have been published. Hospital-based data suggest that lymphomas of small bowel are more common than carcinomas. In conclusion, the incidence of large and small bowel adenomas and cancers is low in Indians. Increase in the incidence of large bowel cancers in immigrants and urban Indians compared to rural populations supports a role for environmental risk factors including diet. High rates of rectal cancers in young Indians could suggest a different etiopathogenesis, which is neither inherited nor traditional diet-related.  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