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   847篇
  免费   53篇
  国内免费   6篇
儿科学   38篇
妇产科学   23篇
基础医学   64篇
口腔科学   20篇
临床医学   62篇
内科学   116篇
皮肤病学   18篇
神经病学   18篇
特种医学   181篇
外科学   81篇
综合类   46篇
预防医学   29篇
眼科学   131篇
药学   25篇
中国医学   1篇
肿瘤学   53篇
  2023年   3篇
  2022年   7篇
  2021年   8篇
  2020年   7篇
  2019年   6篇
  2018年   9篇
  2017年   10篇
  2016年   16篇
  2015年   19篇
  2014年   12篇
  2013年   18篇
  2012年   27篇
  2011年   29篇
  2010年   21篇
  2009年   25篇
  2008年   44篇
  2007年   33篇
  2006年   39篇
  2005年   34篇
  2004年   25篇
  2003年   28篇
  2002年   22篇
  2001年   25篇
  2000年   20篇
  1999年   21篇
  1998年   27篇
  1997年   44篇
  1996年   31篇
  1995年   23篇
  1994年   18篇
  1993年   16篇
  1992年   12篇
  1991年   12篇
  1990年   16篇
  1989年   10篇
  1988年   17篇
  1987年   24篇
  1986年   25篇
  1985年   16篇
  1984年   18篇
  1983年   6篇
  1982年   13篇
  1981年   15篇
  1980年   14篇
  1979年   4篇
  1978年   7篇
  1977年   8篇
  1976年   7篇
  1975年   5篇
  1949年   2篇
排序方式: 共有906条查询结果,搜索用时 415 毫秒
71.
72.
Four hypomelic children of abnormally short stature had slight intellectual defect, melanotic skin, and some facial features in common. 3 were followed to the age of 23-26 years, and they remained small and pigmented.  相似文献   
73.
p53 gene mutations in Barrett's epithelium and esophageal cancer   总被引:14,自引:0,他引:14  
Genomic DNA was extracted from archival pathology specimens comprising 10 squamous and 14 adenocarcinomas, including 7 with Barrett's epithelium adjacent to tumor, and corresponding normal esophagus from the resection margin. The polymerase chain reaction was used to amplify selected exons of p53 which were analyzed for mutations using single-strand conformation polymorphism analysis. Mutations were localized to exon 8 for 1 adenocarcinoma and to exon 5 for 1 squamous tumor and 4 of 7 Barrett's specimens. Sequencing confirmed mutations at codons 273 (CGT----CAT; adenocarcinoma) and 176 (TGC----TTC; squamous) and in Barrett's epithelium at codons 152 (CCG----CTG), 155 (ACC----GCC) and 175 (CGC----CAC). Specimens of Barrett's epithelium from separate sites had identical p53 mutations suggesting a clonal origin. Cancers arising in mutant epithelium did not have mutations corresponding to those found in the Barrett's specimens suggesting that other events are required for tumorigenesis.  相似文献   
74.

Background  

This paper reports population-based data on the prevalence and causes of visual impairment among children and adults in Botucatu, Brazil.  相似文献   
75.
76.
OBJECTIVE: To study patterns of failure following primary antireflux surgery and to evaluate efficacy of reoperation using a left thoracoabdominal Collis gastroplasty and selective fundoplication. METHODS: Thirty-one patients who underwent reoperative antireflux surgery between 1991 and 2000 were studied. Transabdominal fundoplication had been performed in 21 patients, and ten patients had a partial fundoplication by left thoracotomy, 1-33 years (mean, 15 years) previously. All patients presented with clinically disabling symptoms. Objective studies documented for all patients, a disrupted fundoplication, a short esophagus, and an associated hiatus hernia (Type I: 21 patients, 68%; Type III: ten patients, 32%), esophagitis (nine patients, 29%), and Barrett's mucosa (five patients, 16%). Abnormal esophageal motility was found in nine of 26 (36%) patients studied. All patients were reoperated using a left thoracoabdominal approach, with epidural analgesia. A Collis gastroplasty was used to lengthen the esophagus, incorporating a complete (24 patients, 77%) or partial (seven patients, 23%) fundoplication based of preoperative esophageal function studies. RESULTS: There was no perioperative mortality. Median length of hospitalization was 8 days, and was uncomplicated for 18 (58%) patients. Postoperative morbidity was considered minimal, and comprised left lower lobe infiltrates (six patients, 19%), atrial fibrillation (three patients, 10%), urinary tract infection (one patient, 3%), superficial wound infection (one patient, 3%), aspiration (one patient, 3%), and nausea (one patient, 3%). Median follow-up was 42 months (6-105 months), and was complete for 29 patients. Six patients (21%) had moderate-severe post-thoracotomy pain, for up to 18 months postoperatively, and five patients (17%) required esophageal dilation, ranging from two to six dilations within the first 6 months after surgery. Overall, 93% (27/29) of patients were satisfied with the results of surgery, in terms of quality of swallowing and control of preoperative symptoms. CONCLUSIONS: In this series, failure of primary antireflux surgery was related to short esophagus. Intermediate-term subjective results of reoperative antireflux surgery were good for selected patients who undergo esophageal lengthening and fundoplication. The left thoracoabdominal approach was safe, generally well tolerated, and provided excellent exposure of the esophagogastric junction for complex reoperative antireflux surgery.  相似文献   
77.
A 16-y-old boy who had undergone bone marrow transplantation for relapsed acute lymphoblastic leukaemia developed liver cirrhosis and refractory ascites, which did not respond to salt restriction, diuretics and abdominal paracentesis. Liver transplantation was not feasible because of poor nutritional status, pre-existing renal dysfunction and uncertainty about the prognosis of his leukaemia. The patient underwent a successful transjugular intrahepatic portosystemic shunt (TIPS), with immediate resolution of ascites, enabling cessation of diuretics and improvement in nutritional status. At 24 mo following TIPS there has been no re-accumulation of ascites. CONCLUSION: TIPS may have a role in the management of refractory ascites secondary to liver cirrhosis in selected children.  相似文献   
78.
目的 探讨双侧唇裂继发畸形的解剖学修复。方法 采用埋没导引缝合针缝合法 ,对于引起畸形的主要因素 :鼻翼软骨向两侧移位 ,鼻降肌挛缩 ,口轮匝肌移位 ,鼻孔底瘢痕挛缩等进行彻底松解后 ,牢固准确地复位、固定 ,以恢复其正常的解剖关系。结果 自 1998年以来 ,共收治 2 6例双侧唇裂继发畸形患者 ,除 1例叉状皮瓣远端坏死外 ,余均顺利成功。随访 1~ 2年效果满意。结论 本手术不仅简单省时 ,而且能达到从解剖学角度修复畸形  相似文献   
79.
Gastrointestinal teratomas are uncommon, benign neoplasms that occur primarily in children. A retrospective review of five cases (two gastric, one pancreatic, one mesenteric, and one in the lesser omentum) is presented with emphasis on the computed tomographic and ultrasonographic appearances. Principal findings are a well-defined mass with separate cystic and solid components of varying proportions, discrete areas with densities similar to that of fat, or coarse, globular calcifications within the solid component. Recognition of these findings may allow the radiologist to make a correct preoperative diagnosis of teratoma.  相似文献   
80.
Swett  HA; Fisher  PR; Cohn  AI; Miller  PL; Mutalik  PG 《Radiology》1989,172(2):487-493
Conventional computer-based medical expert systems deliver advice to physicians as written text. While such advice is useful, it has distinct limitations in a visually oriented discipline such as diagnostic radiology, in which decisions often depend on pattern recognition and appreciation of subtle morphologic features. The authors developed a prototype expert computer system, IMAGE/ICON, which displays groups of images sorted into a series of axes based on different ways in which they may be similar. They may share a common feature, group of features, causes, or clinical setting. IMAGE/ICON may display examples of morphologic variations of a dominant finding or a spectrum of abnormalities seen in an specific disease or group of diseases. The system also assembles a written analysis of key features of a case. Such a tool may be useful as a diagnostic aid or for continuing medical education. It is likely to have particular impact in the form of an intelligent radiologic workstation, as picture archiving and communication systems become available.  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