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   59155篇
  免费   4365篇
  国内免费   1712篇
耳鼻咽喉   225篇
儿科学   1279篇
妇产科学   1186篇
基础医学   6489篇
口腔科学   1066篇
临床医学   6376篇
内科学   12656篇
皮肤病学   456篇
神经病学   1806篇
特种医学   853篇
外国民族医学   12篇
外科学   3003篇
综合类   8041篇
现状与发展   9篇
预防医学   6858篇
眼科学   414篇
药学   7703篇
  14篇
中国医学   1798篇
肿瘤学   4988篇
  2024年   137篇
  2023年   824篇
  2022年   1945篇
  2021年   2417篇
  2020年   1845篇
  2019年   2115篇
  2018年   2181篇
  2017年   1841篇
  2016年   2089篇
  2015年   2334篇
  2014年   3688篇
  2013年   4403篇
  2012年   3833篇
  2011年   4097篇
  2010年   3152篇
  2009年   2884篇
  2008年   3120篇
  2007年   2957篇
  2006年   2539篇
  2005年   2230篇
  2004年   1874篇
  2003年   1489篇
  2002年   1220篇
  2001年   1072篇
  2000年   887篇
  1999年   834篇
  1998年   689篇
  1997年   612篇
  1996年   488篇
  1995年   411篇
  1994年   377篇
  1993年   300篇
  1992年   275篇
  1991年   225篇
  1990年   159篇
  1989年   153篇
  1988年   109篇
  1987年   140篇
  1985年   362篇
  1984年   410篇
  1983年   267篇
  1982年   320篇
  1981年   319篇
  1980年   301篇
  1979年   261篇
  1978年   196篇
  1977年   150篇
  1976年   203篇
  1975年   138篇
  1974年   126篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
1.
A 25-year-old, emaciated man without medical treatment was found to have died suddenly at home by his mother. At autopsy, there were no injuries to his body, but significant circulatory insufficiency was observed. Electron microscopy revealed abnormal mitochondria in cells of the cardiac conduction system. The conduction system was filled with mitochondrial size abnormalities and mitochondrial cristae abnormalities. No notable abnormal findings were observed in other organs. Genetic examination of the blood revealed the mitochondrial pathogenetic variant m.3243A>G. Epileptic seizures, diabetic ketoacidosis, and hyperosmolar hyperglycemic state were unlikely to be the cause of sudden death. The cause of death was diagnosed as arrhythmia possibly induced by the failure of the cardiac conduction system due to mitochondrial disease. This is a rare case of sudden death caused by an accumulation of abnormal mitochondria in the cardiac conduction system.  相似文献   
2.
Treatment guidelines for management of uncomplicated gonorrhoeae have been recently modified owing to alarming upsurge in azithromycin resistance. This study investigated the prevalence and genetic determinants of gonococcal azithromycin resistance in India. Four (5.7%) of 70 gonococcal isolates were resistant to azithromycin. Of 16 isolates investigated for molecular mechanisms of resistance, 13 (81.3%) and 6 (37.5%) isolates exhibited mutations in coding and promoter regions of mtrR gene, respectively. However, ermA, ermB and ermC genes or mutations in rrl gene were absent in all isolates. Azithromycin resistance is low in India posing no immediate threat to use of dual-therapy for syndromic management.  相似文献   
3.
4.
Sinus venosus atrial septal defect (SV‐ASD) usually coexists with partial anomalous pulmonary vein connection (PAPVC). It is a difficult diagnosis in transthoracic echocardiography (TTE) due to eccentric position of defects. We present a rare case of atypical anatomical variation in PAPVC, which was never described before. Two right pulmonary veins drained into superior vena cava, which overrode SV‐ASD and interatrial septum, a third pulmonary vein into the right atrium. Complete diagnosis could not be set after TTE, nor transesophageal echocardiography, whereas angio‐CT was finally conclusive. This diagnostic approach allowed the surgical planning.  相似文献   
5.
BackgroundCampylobacter is the most common cause of infectious diarrhea in agammaglobulinemia patients. These infections can be severe, prolonged, and recurrent in such patients.Patient and methodsWe report a 29-year-old male patient with X-linked agammaglobulinemia with Campylobacter coli enterocolitis that persisted for nine months despite multiple 10- to 14-day courses of oral ciprofloxacin and azithromycin.ResultsThe isolate was highly resistant to ciprofloxacin, erythromycin, tetracycline, and fosfomycin. The patient failed to respond to intravenous ertapenem, 1.0 g/day for two weeks, to which the pathogen was susceptible. He was finally cured with oral gentamicin, 80 mg four times daily, and stool cultures remained negative during the seven-month follow-up.ConclusionOral aminoglycoside might be the most appropriate choice for eradication of persistent Campylobacter in the intestinal tract for macrolide- and fluoroquinolone-resistant isolate in agammaglobulinemia patients with chronic diarrhea or relapsing systemic infections.  相似文献   
6.
7.
This is the first Japanese autopsy case of Leucine-rich repeat kinase 2 (LRRK2) G2019S mutation with atypical TDP43 proteinopathy. Our case is important that presented clinically dysphagia and pathologically TDP-43 proteinopathy. TDP43 may play an important role of clinical presentation with LRRK2 G2019S mutation carriers.  相似文献   
8.
PurposeThe purpose of this study was to determine whether computed tomography (CT)-based machine learning of radiomics features could help distinguish autoimmune pancreatitis (AIP) from pancreatic ductal adenocarcinoma (PDAC).Materials and MethodsEighty-nine patients with AIP (65 men, 24 women; mean age, 59.7 ± 13.9 [SD] years; range: 21–83 years) and 93 patients with PDAC (68 men, 25 women; mean age, 60.1 ± 12.3 [SD] years; range: 36–86 years) were retrospectively included. All patients had dedicated dual-phase pancreatic protocol CT between 2004 and 2018. Thin-slice images (0.75/0.5 mm thickness/increment) were compared with thick-slices images (3 or 5 mm thickness/increment). Pancreatic regions involved by PDAC or AIP (areas of enlargement, altered enhancement, effacement of pancreatic duct) as well as uninvolved parenchyma were segmented as three-dimensional volumes. Four hundred and thirty-one radiomics features were extracted and a random forest was used to distinguish AIP from PDAC. CT data of 60 AIP and 60 PDAC patients were used for training and those of 29 AIP and 33 PDAC independent patients were used for testing.ResultsThe pancreas was diffusely involved in 37 (37/89; 41.6%) patients with AIP and not diffusely in 52 (52/89; 58.4%) patients. Using machine learning, 95.2% (59/62; 95% confidence interval [CI]: 89.8–100%), 83.9% (52:67; 95% CI: 74.7–93.0%) and 77.4% (48/62; 95% CI: 67.0–87.8%) of the 62 test patients were correctly classified as either having PDAC or AIP with thin-slice venous phase, thin-slice arterial phase, and thick-slice venous phase CT, respectively. Three of the 29 patients with AIP (3/29; 10.3%) were incorrectly classified as having PDAC but all 33 patients with PDAC (33/33; 100%) were correctly classified with thin-slice venous phase with 89.7% sensitivity (26/29; 95% CI: 78.6–100%) and 100% specificity (33/33; 95% CI: 93–100%) for the diagnosis of AIP, 95.2% accuracy (59/62; 95% CI: 89.8–100%) and area under the curve of 0.975 (95% CI: 0.936–1.0).ConclusionsRadiomic features help differentiate AIP from PDAC with an overall accuracy of 95.2%.  相似文献   
9.
10.
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