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   3319篇
  免费   227篇
  国内免费   15篇
耳鼻咽喉   21篇
儿科学   19篇
妇产科学   25篇
基础医学   435篇
口腔科学   111篇
临床医学   275篇
内科学   911篇
皮肤病学   20篇
神经病学   449篇
特种医学   66篇
外科学   665篇
综合类   8篇
预防医学   98篇
眼科学   23篇
药学   142篇
中国医学   9篇
肿瘤学   284篇
  2023年   22篇
  2022年   44篇
  2021年   81篇
  2020年   45篇
  2019年   61篇
  2018年   88篇
  2017年   81篇
  2016年   91篇
  2015年   85篇
  2014年   95篇
  2013年   188篇
  2012年   249篇
  2011年   246篇
  2010年   126篇
  2009年   108篇
  2008年   201篇
  2007年   228篇
  2006年   196篇
  2005年   205篇
  2004年   200篇
  2003年   172篇
  2002年   157篇
  2001年   54篇
  2000年   53篇
  1999年   55篇
  1998年   30篇
  1997年   28篇
  1996年   22篇
  1995年   10篇
  1994年   17篇
  1993年   21篇
  1992年   22篇
  1991年   32篇
  1990年   31篇
  1989年   28篇
  1988年   20篇
  1987年   21篇
  1986年   26篇
  1985年   16篇
  1984年   11篇
  1983年   6篇
  1982年   11篇
  1981年   7篇
  1980年   6篇
  1979年   15篇
  1978年   5篇
  1977年   6篇
  1976年   9篇
  1975年   6篇
  1969年   3篇
排序方式: 共有3561条查询结果,搜索用时 15 毫秒
51.
52.
53.
The present studies identify the steric factors involved in the hydration of epoxide intermediates of some pesticides by hepatic epoxide hydrolase. Investigations were carried out regarding the formation of reactive epoxide intermediates and their different interactions with the hepatic epoxide hydrolase. Some pesticides and their parent epoxides were selected on he basis of the steric hindrance on the oxirane ring. The results indicate that the inhibition of this enzyme depends on the steric hindrance produced by substituents on the oxirane ring of these pesticides. Mono- and di-substituted oxiranes are good substrates of the epoxide hydrolase and non-competitive inhibitors of the hydration of styrene oxide, while tri-substituted epoxides are virtually inactive on inhibiting the hepatic epoxide hydrolase activity.  相似文献   
54.
55.
BACKGROUND: The healing of a metaphyseal fracture line is a major problem in cases of distal tibial fracture treated with external fixation. METHODS: Forty-seven distal tibial fractures treated with two-ring Ilizarov hybrid external fixation (16 AO/OTA type A and 31 type C, 10 open) were followed up. Fracture reduction and union time was evaluated and IOWA and RAND 36-Item Health Survey scores were used to assess functional outcome. RESULTS: Thirty-five fractures united uneventfully in a median time of 20 weeks, but 12 fractures needed additional procedures because of delayed union. According to univariate analysis, the risk factors for a longer time needed for fracture union were translational displacement and current smoking, and the risk factors for reoperation because of delayed union translational displacement fibular fracture fixation, and the number of cigarettes smoked per day. In multivariate analysis, translational displacement was a risk factor for both longer time to fracture union and reoperation and fibular fracture fixation was a risk factor for reoperation. If the translational displacement was less than 3 mm, the reoperation rate was 6%, whereas if the displacement was more than 3 mm, it was 83%. Reoperation was performed on 50% of the patients who underwent fibular fixation and on 15% of the patients who did not undergo fibular fixation. There were only marginal decreases in the range of motion and arthritis scores in the AO/OTA fracture types other than type C3. There were no significant differences in RAND 36 scores between the general Finnish population aged 18 to 64 years and our patients. CONCLUSIONS: Hybrid external fixation of distal tibial fractures is associated with delayed union, which is closely related to the degree of residual translational displacement after reduction. Fixation of an associated fibular fracture does not help to achieve better contact in the tibial fracture and increases the risk of delayed union.  相似文献   
56.
57.
58.
Clinical Rheumatology - Myasthenia gravis is an autoimmune disease affecting the neuromuscular junction, often associated with other autoimmune diseases, including rheumatoid arthritis. Patients...  相似文献   
59.
The purpose of the study was to examine the safety and efficacy of two different formulations of mycophenolic acid (MPA)-eluting Duraflex stents on coronary de novo lesions. Recent data indicate that local delivery of MPA in the porcine overstretch coronary model significantly reduces neointimal hyperplasia (NIH). Patients were divided into three consecutive groups. The first (n=50) and second (n=55) groups received moderate- and slow-release MPA-eluting Duraflex stent, respectively. The last group (n=50) received the bare metal Duraflex stent. Clinical, angiographic, and intravascular ultrasound analysis were performed at 6-month follow-up. All stents were successfully deployed and patients were discharged home without clinical events. Compared to controls, 6-month in-lesion and in-stent minimum luminal diameter as well as late lumen loss were not significantly different in the moderate- and slow-release treatment groups. At follow-up, percentage obstruction and NIH volume were also similar between the three groups. At 30 days and 6 and 12 months, there were no differences noted between the three groups with respect to major adverse cardiac events as well as the individual rates of mortality, myocardial infarction, or repeat revascularization. There were no cases of subacute or late thrombosis. In this feasibility trial, the MPA-eluting Duraflex stents in either slow- or moderate-release formulations were well tolerated, but showed no benefit for treatment of coronary lesions when compared to controls. Further testing with different drug dosing or delivery rate might improve these results.  相似文献   
60.
Because swine influenza virus infection is seldom diagnosed in humans, its frequency might be underestimated. We report a immunocompromised hematologic patient with swine influenza A(H3N2) virus in 2014 in Italy. Local pigs were the source of this human infection.  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