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   9336篇
  免费   447篇
  国内免费   95篇
耳鼻咽喉   95篇
儿科学   182篇
妇产科学   169篇
基础医学   1086篇
口腔科学   231篇
临床医学   804篇
内科学   2632篇
皮肤病学   164篇
神经病学   1035篇
特种医学   279篇
外科学   1165篇
综合类   28篇
预防医学   441篇
眼科学   110篇
药学   564篇
中国医学   43篇
肿瘤学   850篇
  2023年   72篇
  2022年   166篇
  2021年   283篇
  2020年   164篇
  2019年   201篇
  2018年   265篇
  2017年   180篇
  2016年   243篇
  2015年   294篇
  2014年   329篇
  2013年   507篇
  2012年   780篇
  2011年   677篇
  2010年   424篇
  2009年   399篇
  2008年   615篇
  2007年   656篇
  2006年   579篇
  2005年   629篇
  2004年   541篇
  2003年   446篇
  2002年   433篇
  2001年   66篇
  2000年   54篇
  1999年   54篇
  1998年   78篇
  1997年   73篇
  1996年   42篇
  1995年   50篇
  1994年   43篇
  1993年   36篇
  1992年   32篇
  1991年   39篇
  1990年   31篇
  1989年   29篇
  1988年   30篇
  1987年   28篇
  1986年   26篇
  1985年   30篇
  1984年   24篇
  1983年   19篇
  1982年   19篇
  1981年   24篇
  1980年   35篇
  1979年   13篇
  1978年   10篇
  1977年   12篇
  1976年   12篇
  1975年   12篇
  1974年   6篇
排序方式: 共有9878条查询结果,搜索用时 15 毫秒
131.
132.
133.
The aim of our study is to compare patent foramen ovale (PFO) closure versus medical treatment and antiplatelet versus anticoagulant therapy in patients with cryptogenic stroke (CS) and PFO. We conducted a systematic review and meta-analysis with trial sequential analysis (TSA) of randomized trials. Primary outcomes are stroke or transient ischemic attack (TIA) and all-cause mortality. Secondary outcomes are peripheral embolism, bleeding, serious adverse events, myocardial infarction and atrial dysrhythmias. We performed an intention to treat meta-analysis with a random-effects model. We include six trials (3677 patients, mean age 47.3 years, 55.8% men). PFO closure is associated with a lower recurrence of stroke or TIA at a mean follow-up of 3.88 years compared to medical therapy [risk ratio (RR) 0.55, 95% CI 0.38–0.81; I2?=?40%]. The TSA confirms this result. No difference is found in mortality (RR 0.74, 95% CI 0.35–1.60; I2?=?0%), while PFO closure is associated with a higher incidence of atrial dysrhythmias (RR 4.55, 95% CI 2.16–9.60; I2?=?25%). The rate of the other outcomes is not different among the two groups. The comparison between anticoagulant and antiplatelet therapy shows no difference in terms of stroke recurrence, mortality and bleeding. There is conclusive evidence that PFO closure reduces the recurrence of stroke or TIA in patients younger than 60 years of age with CS. More data are warranted to assess the consequences of the increase in atrial dysrhythmias and the advantage of PFO closure over anticoagulants.  相似文献   
134.
Red blood cell (RBC) aging in the blood bank is characterized by the accumulation of a significant number of biochemical and morphologic alterations. Recent mass spectrometry and electron microscopy studies have provided novel insights into the molecular changes underpinning the accumulation of storage lesions to RBCs in the blood bank. Biochemical lesions include altered cation homeostasis, reprogrammed energy, and redox metabolism, which result in the impairment of enzymatic activity and progressive depletion of high‐energy phosphate compounds. These factors contribute to the progressive accumulation of oxidative stress, which in turn promotes oxidative lesions to proteins (carbonylation, fragmentation, hemoglobin glycation) and lipids (peroxidation). Biochemical lesions negatively affect RBC morphology, which is marked by progressive membrane blebbing and vesiculation. These storage lesions contribute to the altered physiology of long‐stored RBCs and promote the rapid clearance of up to one‐fourth of long‐stored RBCs from the recipient's bloodstream after 24 hours from administration. While prospective clinical evidence is accumulating, from the present review it emerges that biochemical, morphologic, and omics profiles of stored RBCs have observable changes after approximately 14 days of storage. Future studies will assess whether these in vitro observations might have clinically meaningful effects.  相似文献   
135.
Minimal access reoperative mitral and aortic valve surgery   总被引:1,自引:0,他引:1  
Minimally invasive cardiac surgery has allowed surgeons to perform valve procedures with a morbidity and mortality comparable with conventional resternotomy approaches while reducing postoperative ventilatory and intensive care unit requirements and overall hospital length of stay. Additionally, patient satisfaction with rapid recovery, earlier return to work, and improved cosmetic results has pushed the pendulum of reoperative valve surgery towards minimally invasive techniques. We reviewed our institutional data consisting of 129 patients requiring reoperative valve surgery over the past 4 years, which was accomplished using these minimally invasive approaches.  相似文献   
136.
137.
This study analyzed the relations and time-related changes in eligibility for cardiac resynchronization therapy and prophylactic defibrillator implantation in 161 potential candidates for heart transplantation. Although up to 62% of patients who fulfilled the severity criteria for heart transplantation were eligible for either device, this percentage increased as clinical/instrumental parameters of heart failure severity worsened.  相似文献   
138.
Cytokines appear to be involved in the pathogenesis of Alzheimer's Disease (AD). Their modulation by treatment has been investigated only in a few studies. The aim of our study was to evaluate the effect of acetylcholinesterase inhibitors (AChEI) on Interleukin-4 (IL-4) production in AD patients. IL-4 levels were measured by ELISA on peripheral blood mononuclear cell cultures in the presence or absence of Concanavalin A or Phytohaemagglutinin. Linear regression analysis shows that patients who have been treated, have higher levels of IL-4 independently from age, gender and comorbidity. The increased production of IL-4 in AChEI treated patients might represent an additional mechanism through which AChEI act on AD progression.  相似文献   
139.
140.
Clinical and Experimental Medicine - Patients with lymphoproliferative disorders, candidate to autologous stem cell transplantation (ASCT), require mobilization with chemotherapy and granulocyte...  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