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   4080篇
  免费   319篇
  国内免费   20篇
耳鼻咽喉   31篇
儿科学   128篇
妇产科学   61篇
基础医学   647篇
口腔科学   86篇
临床医学   490篇
内科学   794篇
皮肤病学   96篇
神经病学   395篇
特种医学   244篇
外科学   488篇
综合类   101篇
一般理论   5篇
预防医学   411篇
眼科学   65篇
药学   228篇
中国医学   10篇
肿瘤学   139篇
  2021年   59篇
  2020年   46篇
  2019年   70篇
  2018年   69篇
  2017年   65篇
  2016年   79篇
  2015年   62篇
  2014年   90篇
  2013年   153篇
  2012年   159篇
  2011年   181篇
  2010年   133篇
  2009年   130篇
  2008年   132篇
  2007年   150篇
  2006年   136篇
  2005年   158篇
  2004年   134篇
  2003年   148篇
  2002年   138篇
  2001年   111篇
  2000年   117篇
  1999年   101篇
  1998年   84篇
  1997年   77篇
  1996年   60篇
  1995年   52篇
  1994年   60篇
  1993年   48篇
  1992年   67篇
  1991年   68篇
  1990年   61篇
  1989年   80篇
  1988年   75篇
  1987年   87篇
  1986年   58篇
  1985年   59篇
  1984年   59篇
  1983年   55篇
  1982年   44篇
  1980年   45篇
  1979年   39篇
  1978年   52篇
  1977年   36篇
  1976年   36篇
  1975年   34篇
  1974年   34篇
  1973年   33篇
  1972年   42篇
  1970年   29篇
排序方式: 共有4419条查询结果,搜索用时 31 毫秒
11.
12.
Gastroesophageal reflux disease (GERD) is the most common disease of the upper gastrointestinal tract. With the introduction of proton pump inhibitors medical treatment of GERD has been significantly improved. However, the development of laparoscopic antireflux surgery resulted in an increasing interest of surgeons in this disease. An interactive meeting was organized in order to develop an agreement between gastoenterologists and surgeons regarding therapeutic decisions and this is the main topic of this paper.  相似文献   
13.
We present two children with seizures and other signs of cerebral involvement at the outset of acute inflammatory demyelinating polyneuropathy, consistent with a diagnosis of encephalomyeloradiculoneuropathy. One child had a recurrence associated with mild central dysfunction and improved during therapy with corticosteroids. Both children recovered completely. Both acute and relapsing inflammatory demyelinating neuropathy may be accompanied by cerebral dysfunction, expanding the clinical spectrum of encephalomyeloradiculoneuropathy.  相似文献   
14.
Progabide, a recently introduced gamma-aminobutyric acid mimetic, is currently undergoing clinical evaluation for a variety of convulsive disorders. We describe a patient in whom severe hepatic failure developed after four weeks of Progabide therapy. The patient's course was marked by encephalopathy, jaundice, hypoglycemia, markedly elevated serum aminotransferase levels, and prolongation of the prothrombin time. Liver biopsy showed extensive hepatocellular necrosis. The patient recovered slowly after discontinuation of the drug. The finding of eosinophilia and increased serum IgE suggests an immunologically mediated mechanism for the Progabide-induced hepatic injury. Alternatively, the lipophilic moiety of Progabide may interact with hepatocyte cell membrane lipids leading to toxic injury. We conclude that Progabide may occasionally cause severe hepatic injury.  相似文献   
15.
16.
17.
18.
Although extensively pursued, the central respiratory neurons have remained elusive. We departed from the more conventional physiologic and morphologic methods of system and tissue examination and cultured dissociated fetal rat cells (Fitzgerald et al., J Neurosci Res 33:579-589, 1992) from the area of the nucleus ambiguus and the nucleus tractus solitarius located within the 2 mm rostral to the obex. Pacemaker-like cells, with a regular single or bursting activity, studied at 3-5 weeks of age, responded to very small pulses of CO2 (50 ms) and low pH with an increase in spike frequency and a decrease in spike amplitude. Other irregularly beating or silent cells did not respond or else required very large pulses (> 200 ms) to do so. The pacemaker cells also responded to hypoxia induced by administration of sodium hydrosulfite with an increase in spike frequency and amplitude; high oxygen (> 600 torr) and adenosine produced a decrease in electrical activity. Most of these cells were multipolar after staining with antibodies to neuron-specific enolase (NSE) and Fragment C of tetanus toxin. They did not stain for choline acetyltransferase (ChAT). The results suggest that these cultured cells, expressing a phenotype inherently responsive to CO2 and low pH, have the characteristics of central respiratory chemoreceptors, and may be involved in the generation of the respiratory rhythm.  相似文献   
19.
Here we demonstrate that perfused hearts removed from polyarthritic rats develop a pronounced coronary vasoconstriction ex vivo. This vasoconstriction is almost entirely blocked by in vivo pretreatment of the rats with the endothelin receptor antagonist, SB 209670. Thus, inflammatory states may be associated with an increased activity of the endothelin system, leading to vascular dysfunction and vasoconstriction.  相似文献   
20.
Background: Biphasic waveform shocks are more effective than monophasic shocks for transchest ventricular defibrillation, atrial cardioversion, and defibrillation with implantable defibrillators but have not been studied for open chest, intraoperative defibrillation. This prospective, blinded, randomized clinical study compares biphasic and monophasic shock effectiveness and establishes intraoperative energy dose-response curves.

Methods: Patients undergoing cardiothoracic surgery with bypass cardioplegia were randomly assigned to the monophasic or biphasic shock group. Ventricular fibrillation occurring after aortic clamp removal was treated with escalating energies of 2, 5, 7, 10, and 20 J until defibrillation occurred. If ventricular fibrillation persisted, a 20-J crossover shock of the other waveform was used.

Results: Cumulative defibrillation success at 5 J, the primary end point of the study, was higher in the biphasic group than in the monophasic group (25 of 50 vs. 9 of 41 defibrillated;P = 0.011). In addition, the biphasic group required lower threshold energy (6.8 vs. 11.0 J;P = 0.003), less cumulative energy (12.6 vs. 23.4 J;P = 0.002), and fewer shocks (2.5 vs. 3.5;P = 0.002). Crossover-shock effectiveness did not differ between groups. Dose-response curves show biphasic shocks to have higher cumulative success rates at all energies tested.  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