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   2063篇
  免费   131篇
  国内免费   46篇
耳鼻咽喉   20篇
儿科学   22篇
妇产科学   73篇
基础医学   223篇
口腔科学   59篇
临床医学   253篇
内科学   314篇
皮肤病学   16篇
神经病学   168篇
特种医学   38篇
外科学   184篇
综合类   195篇
预防医学   210篇
眼科学   50篇
药学   255篇
中国医学   61篇
肿瘤学   99篇
  2024年   2篇
  2023年   6篇
  2022年   20篇
  2021年   36篇
  2020年   26篇
  2019年   33篇
  2018年   52篇
  2017年   25篇
  2016年   44篇
  2015年   71篇
  2014年   105篇
  2013年   136篇
  2012年   143篇
  2011年   205篇
  2010年   103篇
  2009年   103篇
  2008年   157篇
  2007年   169篇
  2006年   114篇
  2005年   113篇
  2004年   102篇
  2003年   78篇
  2002年   66篇
  2001年   56篇
  2000年   51篇
  1999年   21篇
  1998年   18篇
  1997年   20篇
  1996年   13篇
  1995年   11篇
  1994年   10篇
  1993年   16篇
  1992年   20篇
  1991年   12篇
  1990年   8篇
  1989年   9篇
  1988年   10篇
  1987年   10篇
  1986年   16篇
  1985年   9篇
  1984年   6篇
  1983年   5篇
  1982年   2篇
  1981年   3篇
  1977年   1篇
  1973年   3篇
  1964年   1篇
排序方式: 共有2240条查询结果,搜索用时 15 毫秒
1.
2.
3.
4.
包含颈外静脉的颈阔肌肌皮瓣修复口腔癌切除后缺损   总被引:1,自引:0,他引:1  
目的探讨将颈外静脉包含在颈阔肌肌皮瓣内修复口腔癌切除后缺损的手术方法。方法先形成蒂在颌缘下包含颈外静脉的颈阔肌肌皮瓣,待口腔肿瘤切除后,将肌皮瓣经口底隧道引入口腔修复缺损。结果临床应用17例,肌皮瓣均无血运障碍,100%存活,其中有2例发生口面痿,经换药后痿口完全闭合。结论将颈外静脉包含在颈阔肌肌皮瓣内有助于肌皮瓣血循环的改善和存活率的提高。  相似文献   
5.
Objective: To examine the relationship between ambient lead levels and blood lead levels and to explore the modifiers of the relationship between ambient lead and blood lead. Method: A cross-sectional study was conducted in two lead battery factories. Blood lead level and ambient lead concentration were measured for each participant concurrently. A structured questionnaire was administered to collect sociodemographic characteristics and occupational history. Design: Biological and personal environmental measurements of 219 lead-exposed workers were analyzed by both simple and multiple linear regression. A regression model was selected for interpretation. Results: A high correlation (r=0.62) between ambient lead (PbA) and blood lead (PbB) was observed. In addition, numerous factors, including age, sex, alcohol consumption, personal hygiene practice and type of lead exposure, were also found to influence blood lead levels. Although PbB was highly correlated with PbA, blood lead level may not be effectively lowered by reducing ambient lead level. Based on the regression coefficients, improvement of hygienic practice was more effective at lowering PbB than reducing ambient lead level. Good hygienic practice may be the preferential way to reduce lead exposure in current conditions. Conclusion: Education of correct work practice may be more important than engineering control in the developing countries to lower blood lead levels in lead battery factories. Received: 28 May 1996/Accepted: 30 August 1996  相似文献   
6.
 To monitor the lead hazards in industries and to investigate the prevalence of elevated blood lead levels (BLLs) in lead-exposed workers, a lead surveillance system (PRESS-BLLs) has been established and operated in Taiwan, Republic of China, since July 1993. A cohort of lead-exposed workers who received a periodic annual health examination at 55 accredited hospital laboratories was constructed. A total of 9807 separate BLL measurements were reported to the system in 1994. The mean BLL was 15.8 μg/dl in male workers and 11.6 μg/dl in female workers. The mean BLL of lead-exposed workers was significantly (P<0.05, z-test) higher than that of the general Taiwanese population (8.6 μg/dl for males and 6.7 μg/dl for females). In addition, the BLLs of 983 (10.0%) workers exceeded the regulatory action level (40 μg/dl for males; 30 μg/dl for females). The workplaces and homes of 57% of the workers with elevated BLLs were thoroughly investigated to determine the sources of lead contamination. These actions identified the causes of elevated BLLs and set up strategies to reduce workers’ lead exposure. The establishment of this occupational lead surveillance system represents a method for monitoring of lead hazards from occupational and environmental settings to prevent lead poisoning. The information acquired from the system can help in the setting up of a priority of prevention and the development of control measures. It is also useful for further monitoring of changes in the BLLs of the lead-exposed-worker cohort. The Health Department of Taiwan can use this information to evaluate the effectiveness of current industrial hygiene practice. Subjects with elevated BLLs have been medically treated and placed on long-term follow-up for sequelae. Received: 2 September 1996/Accepted: 29 November 1996  相似文献   
7.
8.
The skeletal extracellular matrix produced by osteoblasts contains the glycoprotein fibronectin (Fn), which regulates the adhesion, differentiation, and function of osteoblasts. Fn fibrillogenesis is involved in the process of bone mineralization. Bone morphogenetic proteins (BMPs) can be isolated from organic bone matrix and are able to initiate de novo cartilage and bone formation. In this study, the effect of BMP-4 on Fn fibrillogenesis in cultured rat osteoblasts was examined. BMP-4 enhanced Fn synthesis and extracellular Fn assembly in primary cultured osteoblasts. In addition, the extracellular assembly of Fn from exogenously applied soluble human Fn was also increased by BMP-4. It has been reported that alpha5beta1 integrin is related to Fn fibrillogenesis. The synthesis of both alpha5 and beta1 integrins was upregulated by BMP-4. Immunocytochemistry showed that the clustering of alpha5 and beta1 integrins was also increased by BMP-4. BMP-4 increased fibril formation of Fn and the adhesion of osteoblasts onto Fn matrix, which was inhibited by disintegrin triflavin and Gly-Arg-Gly-Asp-Ser (GRGDS) peptide. Phosphorylation of extracellular signal-regulated kinase (ERK) and focal adhesion kinase (FAK) was increased by BMP-4. Enhancement of extracellular Fn fibrillogenesis and the mRNA expression of beta1 integrin by BMP-4 were inhibited by ERK kinase (MEK) inhibitor PD98059. These results suggest that the enhancement of extracellular Fn fibrillogenesis by BMP-4 in cultured osteoblasts is related to the increase of the synthesis of Fn and clustering of alpha5 and beta1 integrins. ERK is involved in the signaling pathway of BMP-4 in regulating Fn fibrillogenesis in osteoblasts.  相似文献   
9.
T C Liou  X Z Lin  T T Chang  C Y Lin  P W Lin  Y T Jin  C Y Yu 《Pancreas》1992,7(2):251-256
A 61-year-old man experienced four bouts of pancreatitis in 1 year. Detailed history taking and a series of examinations, including sonography, computed tomography scan, and endoscopic retrograde cholangiopancreatography (ERCP), revealed pancreas divisum on the first admission. He was treated conservatively. However, repeated ERCP on the fourth admission, 1 year later, showed a small filling defect in the tail of the pancreatic duct. A distal pancreatectomy was carried out. Pathological studies revealed a small papillary adenocarcinoma (1.5 x 1.0 x 0.5 cm) confined to the pancreatic duct grossly with minimal parenchymal invasion microscopically. He has been free from cancer and pancreatitis for 13 months since the operation.  相似文献   
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