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   2146476篇
  免费   153720篇
  国内免费   3922篇
耳鼻咽喉   27953篇
儿科学   72135篇
妇产科学   59434篇
基础医学   313566篇
口腔科学   58661篇
临床医学   196269篇
内科学   415305篇
皮肤病学   46045篇
神经病学   173232篇
特种医学   81623篇
外国民族医学   554篇
外科学   313121篇
综合类   46860篇
现状与发展   3篇
一般理论   919篇
预防医学   175780篇
眼科学   47916篇
药学   154506篇
  10篇
中国医学   3788篇
肿瘤学   116438篇
  2018年   30929篇
  2017年   24155篇
  2016年   27720篇
  2015年   21737篇
  2014年   29812篇
  2013年   45608篇
  2012年   63360篇
  2011年   73129篇
  2010年   44644篇
  2009年   41122篇
  2008年   69296篇
  2007年   75373篇
  2006年   65172篇
  2005年   64772篇
  2004年   63180篇
  2003年   61889篇
  2002年   58902篇
  2001年   92130篇
  2000年   94475篇
  1999年   79351篇
  1998年   22648篇
  1997年   20648篇
  1996年   20857篇
  1995年   19918篇
  1994年   18557篇
  1993年   17301篇
  1992年   63543篇
  1991年   62405篇
  1990年   61085篇
  1989年   59011篇
  1988年   54152篇
  1987年   53820篇
  1986年   50867篇
  1985年   48571篇
  1984年   36836篇
  1983年   31741篇
  1982年   19028篇
  1981年   17156篇
  1979年   34673篇
  1978年   25336篇
  1977年   21244篇
  1976年   19967篇
  1975年   21227篇
  1974年   25835篇
  1973年   25164篇
  1972年   23621篇
  1971年   21984篇
  1970年   20637篇
  1969年   19376篇
  1968年   18013篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
101.
Carbon monoxide (CO), a byproduct of heme catalysis, was shown to have potent cytoprotective and anti-inflammatory effects. In vivo recipient CO inhalation at low concentrations prevented ischemia/reperfusion (I/R) injury associated with small intestinal transplantation (SITx). This study examined whether ex vivo delivery of CO in University of Wisconsin (UW) solution could ameliorate intestinal I/R injury. Orthotopic syngenic SITx was performed in Lewis rats after 6 h cold preservation in control UW or UW that was bubbled with CO gas (0.1-5%) (CO-UW). Recipient survival with intestinal grafts preserved in 5%, but not 0.1%, CO-UW improved to 86.7% (13/15) from 53% (9/17) with control UW. At 3 h after SITx, grafts stored in 5% CO-UW showed improved intestinal barrier function, less mucosal denudation and reduced inflammatory mediator upregulation compared to those in control UW. Preservation in CO-UW associated with reduced vascular resistance (end preservation), increased graft cyclic guanosine monophosphate levels (1 h), and improved graft blood flow (1 h). Protective effects of CO-UW were reversed by ODQ, an inhibitor of soluble guanylyl cyclase. In vitro culture experiment also showed better preservation of vascular endothelial cells with CO-UW. The study suggests that ex vivo CO delivery into UW solution would be a simple and innovative therapeutic strategy to prevent transplant-induced I/R injury.  相似文献   
102.
103.
The absence of the temporary incisors could be to a genetic illness or to some multiple premature extractions. These extractions are the aftermaths of the carious lesions or some traumatisms underwent by the temporary incisors. Beyond measure the loss of the space, the premature loss some temporary incisors very often assign the relational development of the child and disturb its psychological development and the aesthetic function. Across some cases clinics, the authors show that the replacement of the temporary incisors is the therapeutic ideal solution. Indeed, the child prosthesis, replacing the temporary absent incisors, solves the psychological, aesthetic and relational problems of the child.  相似文献   
104.
105.
Contour defects resulting in deformity caused by lack of tissue can be improved by conventional surgery using autologous tissue, but there is always a donor site morbidity. Integra has been available since the early 1980's for use in acute burns and more recently in reconstruction. It has been shown histologically to act as a tissue regeneration template. The regenerated dermis is buried under an autologous thin split-skin graft. In this study, the principle of burying Integra (without the silicone layer) has been applied to deep tissue defects in 12 reconstructive cases. Such regenerated tissues survive at least 3 years after burying. Modification to the technique to avoid visible edges are being developed.  相似文献   
106.
Summary The third-stage larvae of Daniconema anguillae Moravec et K?ie, 1987 are found in the eels fins caught from Dringis Lake (Lithuanian National park). The morphology of these larvae is briefly described.  相似文献   
107.
108.
OBJECTIVE: To evaluate the effect of statins on aneurysm growth in a group of consecutive patients under surveillance for infrarenal aortic aneurysms (AAA). MATERIALS AND METHODS: All patients (59 statin users, 91 non-users) under surveillance between January 2002 and August 2005 with a follow-up for aneurysm growth of at least 12 months and a minimum of three diameter evaluations were retrospectively included in the analysis. Multiple regression analysis, weighted with the number of observations, was performed to test the influence of statins on AAA growth rate. RESULTS: During a median period of 3.1 (1.1-13.1) years the overall mean aneurysm growth rate was 2.95+/-2.8 mm/year. Statin users had a 1.16 mm/year lower AAA growth rate compared to non-users (95% CI 0.33-1.99 mm/year). Increased age was associated with a slower growth (-0.09 mm/year per year, p = 0.003). Female gender (+1.82 mm/year, p = 0.008) and aneurysm diameter (+0.06 mm/year per mm, p = 0.049) were associated with increased AAA growth. The use of non-steroidal anti-inflammatory drugs, chronic lung disease, or other cardiovascular risk factors were not independently associated with AAA growth. CONCLUSIONS: Statins appear to be associated with attenuation of AAA growth, irrespective of other known factors influencing aneurysm growth.  相似文献   
109.
The results of lumbar fusion in chronic low back pain (LBP) patients vary considerably, and there is a need for proper patient selection. Lumbosacral orthoses have been widely used to predict outcome, however, with little scientific support. The aim of the present study was to determine the value of a pantaloon cast test in selecting chronic LBP patients for lumbar fusion or conservative management. First, a systematic review of the literature was carried out in which two independent reviewers identified studies in Medline, Cochrane and Current Contents databases. Three papers met the selection criteria. In the only study with a control group, a significantly better outcome after fusion compared to conservative treatment was found in patients who reported significant pain relief while in a cast (i.e. a positive cast test). The results of lumbar fusion, however, were not significantly different for patients with a positive and those with a negative cast test. In addition to the review, a clinical cohort study of 257 LBP patients, who had been allocated to either lumbar fusion or conservative management by a temporary external transpedicular fixation trial, was performed. Prior to allocation, all had undergone a pantaloon cast test. Patients with no history of prior spine surgery and with a positive pantaloon cast test had a better outcome after lumbar fusion than those treated conservatively (P = 0.002, χ 2 test). In patients with previous spine operations the outcomes were poor and the test was of no value. From the literature and the present patient cohort, it was concluded that only in chronic LBP patients without prior spine surgery, a pantaloon cast test with substantial pain relief suggests a favorable outcome of lumbar fusion compared to conservative management. The test has no value in patients who have had previous spine surgery.  相似文献   
110.
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