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   16138篇
  免费   849篇
  国内免费   666篇
耳鼻咽喉   513篇
儿科学   1035篇
妇产科学   122篇
基础医学   482篇
口腔科学   60篇
临床医学   1664篇
内科学   2793篇
皮肤病学   29篇
神经病学   108篇
特种医学   1149篇
外国民族医学   2篇
外科学   4772篇
综合类   2179篇
预防医学   409篇
眼科学   410篇
药学   853篇
  4篇
中国医学   568篇
肿瘤学   501篇
  2024年   27篇
  2023年   206篇
  2022年   429篇
  2021年   561篇
  2020年   487篇
  2019年   485篇
  2018年   487篇
  2017年   419篇
  2016年   565篇
  2015年   525篇
  2014年   1010篇
  2013年   924篇
  2012年   880篇
  2011年   1033篇
  2010年   887篇
  2009年   887篇
  2008年   898篇
  2007年   938篇
  2006年   835篇
  2005年   682篇
  2004年   579篇
  2003年   464篇
  2002年   433篇
  2001年   375篇
  2000年   318篇
  1999年   247篇
  1998年   229篇
  1997年   219篇
  1996年   175篇
  1995年   172篇
  1994年   134篇
  1993年   100篇
  1992年   103篇
  1991年   82篇
  1990年   109篇
  1989年   70篇
  1988年   92篇
  1987年   57篇
  1986年   57篇
  1985年   70篇
  1984年   77篇
  1983年   40篇
  1982年   58篇
  1981年   45篇
  1980年   42篇
  1979年   41篇
  1978年   25篇
  1977年   21篇
  1976年   22篇
  1975年   10篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
We report on the vaginal mucosal folds (VMF) at the urethral external meatus. Resection of the VMF reduces the dispersed micturition and other urinary symptoms. EDITORIAL COMMENT: The investigators describe the presence of a vaginal mucosal fold (VMF) just dorsal to the urethral meatus and its relationship to voiding abnormalities. VMF were found on physical examination in 8.9% of the clinic population, all of whom complained of dispersed micturition, and 79% also experienced other voiding abnormalities. The complaint of dispersed micturition was successfully treated with excision of the VMF, and the other associated symptoms were improved. This structure should be routinely looked for on physical examination, especially in patients with voiding symptoms. Only further investigation of this newly described entity at other centers around the world will determine the incidence of the anatomic finding and the prevalence of associated voiding disturbances across different populations.  相似文献   
32.
Prune belly syndrome (PBS) has been recognized since 1950 as the triad of absent abdominal wall musculature, undescended testes, and urinary tract anomalies. The etiology, however, remains uncertain. Theories of mesenchymal maldevelopment, obstruction, and genetic origin have been proposed. To evaluate the role of lower urinary tract obstruction as it relates to prostatic development and PBS, we studied the lower urinary tract of 15 cases of PBS, 8 cases of posterior urethral values (PUV), and 34 age-matched controls. It is generally accepted that prostatic growth and development are dependent on mesenchymal-epithelial interactions. We evaluated the mesenchymal and epithelial differentiation and relationships, and found distinctly different and consistent abnormalities between PBS and PUV as compared with one another and controls. The findings suggest that in PBS, prostatic growth and development are hindered because of destruction or absence of the appropriate primitive mesenchyme. Our studies could not definitely exclude very early obstruction as a cause of the findings because of lack of appropriate fetal material.  相似文献   
33.
When nasotracheal intubation with a fiberoptic bronchoscope is performed, the tube may be blocked in the nasal cavity or larynx, resulting in several complications including epistaxis and hoarseness. We review the causes and complications of tube blockage and discuss optimal techniques for minimizing it.  相似文献   
34.
35.
胆道支撑管显影材料的制备及体外细胞毒性评价   总被引:4,自引:0,他引:4  
目的 探讨新型显影胆道支撑管材料制备的可行性,对构建出的材料进行体外细胞毒性评价和筛选。方法 选择具有X线下显影特性的基础材料A、B、C,分别与硅橡胶生胶共混炼,模压后分别得到相应的显影复合材料甲、乙、丙,经一段和二段硫化过程完成加工。采用MTT法作为体外细胞毒性评价的方法,测定参比对照材料和新材料的50%浓度的浸提液对小鼠成纤维细胞的增殖率的影响,确定细胞毒性级别。结果 新材料甲、乙、丙在x线下影像清晰。甲、乙材料的细胞毒性级别为零,丙材料细胞毒性级别为2。结论 构建出在X线下显影的弹性体材料可行。材料甲、乙是制造新型胆道支撑管的初选材料,材料丙无应用的价值。  相似文献   
36.
Background : Pelvi-ureteric junction obstruction has been increasingly diagnosed in infants, mostly as a consequence of antenatal ultrasound examinations. Methods : Of 55 infants below the age of 12 months who underwent dismembered pyeloplasty over a 7-year period, we aimed to determine the patterns and outcome of associated vesico-ureteric reflux that was present in 15 (28%) of the 53 infants in whom follow-up was available. Results : A total of eight infants had resolution of their reflux with conservative management and the median time to resolution was 15 months. Five infants proceeded to ureteroneocystotomy. Conclusions : Given the association of vesico-ureteric reflux and pelvi-ureteric junction obstruction, routine cystography is recommended when the diagnosis of pelvi-ureteric junction obstruction is made.  相似文献   
37.
The radiologic findings on conventional examinations (plain films and cholangiograms) in a large group of patients with proven hepatobiliary tuberculosis are reviewed. The plain film findings of large chalky and confluent hepatic calcifications or nodal-type calcifications along the course of the common bile duct are suggestive of hepatobiliary tuberculosis. Small, discrete, scattered calcifications may be mimicked by histoplasmosis but can be differentiated from hepatobiliary tuberculosis. Obstructing defects seen on cholangiography are indicative of tuberculosis when adjacent calcifications are present. The patterns of liver calcifications could provide a clue to the diagnosis of hepatobiliary tuberculosis and its differentiation from liver calcifications of various other etiologies.  相似文献   
38.
A feasibility study was made to examine whether pressure measurements can be used to diagnose vascular obstructions in blood vessels. Distortion of a pressure wave due to an obstruction in an elastic tube was investigated theoretically and experimentally. Linear theory and the method of characteristics were employed in developing mathematical expressions for the distortion of the pressure wave. The quality of the models developed was examined by performing experiments on a latex tube with rigid obstructions. A nonlinear model using the method of characteristics was in good agreement with the experiment data for obstructions with any severity, while a linear model was applicable to small obstructions. The nonlinear model is proposed as a mathematical model for the detection of vascular obstructions by analysing pressure waves.  相似文献   
39.
A case of papillary adenocarcinoma arising in Caroli's disease (CD) in a 25-yr-old woman is reported. The diagnosis of malignancy was made by ultrasound-guided, fine-needle aspiration biopsy (FNAB). As there were no metastasis, a liver transplant was performed and the diagnosis was histologically confirmed. Only 22 cases of malignant transformation of CD have been reported to date, all among middle-aged subjects (mean age: 52 yr) of both sexes. Most of these reported cases (83%) were found to be bile duct adenocarcinomas with occasional reports of hepatocellular and undifferentiated carcinomas. Our case is the youngest reported to date and the first to be diagnosed cytologically.  相似文献   
40.
Corticosteroid therapy in biliary atresia   总被引:4,自引:0,他引:4  
Sixteen patients with biliary atresia had 44 steroid courses for treatment of cholangitis or diminution of bile flow following Kasai hepatic portoenterostomy operations. A "blast" type (high dose/short duration) steroid administration was employed to potentiate the choleretic and anti-inflammatory effect. There was a significant augmentation of bile flow and a reduction in maximum temperature, serum bilirubin, and alkaline phosphatase.  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