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   999262篇
  免费   75359篇
  国内免费   2616篇
耳鼻咽喉   12980篇
儿科学   34531篇
妇产科学   28544篇
基础医学   145529篇
口腔科学   27749篇
临床医学   90445篇
内科学   193952篇
皮肤病学   22956篇
神经病学   79311篇
特种医学   38473篇
外国民族医学   305篇
外科学   149761篇
综合类   23748篇
一般理论   385篇
预防医学   77933篇
眼科学   22649篇
药学   71929篇
  3篇
中国医学   2033篇
肿瘤学   54021篇
  2018年   10579篇
  2017年   8270篇
  2016年   9391篇
  2015年   10645篇
  2014年   14455篇
  2013年   22072篇
  2012年   29092篇
  2011年   30927篇
  2010年   18552篇
  2009年   17498篇
  2008年   28875篇
  2007年   30544篇
  2006年   31050篇
  2005年   29718篇
  2004年   28994篇
  2003年   27861篇
  2002年   26866篇
  2001年   46970篇
  2000年   48086篇
  1999年   40313篇
  1998年   11202篇
  1997年   10111篇
  1996年   10173篇
  1995年   9787篇
  1994年   9101篇
  1993年   8490篇
  1992年   32285篇
  1991年   31497篇
  1990年   31044篇
  1989年   29904篇
  1988年   27203篇
  1987年   27363篇
  1986年   25458篇
  1985年   24618篇
  1984年   18410篇
  1983年   15533篇
  1982年   9297篇
  1981年   8386篇
  1979年   16885篇
  1978年   12233篇
  1977年   10330篇
  1976年   9765篇
  1975年   10194篇
  1974年   12333篇
  1973年   11853篇
  1972年   10892篇
  1971年   10130篇
  1970年   9382篇
  1969年   8729篇
  1968年   8116篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
This study assessed the amount of vascular endothelial growth factor (VEGF) expression and related the findings to new bone formation in the posterior glenoid fossa during stepwise mandibular advancement. A total of 250 female Sprague-Dawley rats, 35 days old, were randomly divided into 10 groups, each including 5 control and 20 experimental rats. Within each group, 10 experimental rats were fitted with functional appliances with a 1-step advancement of 3.5 mm. Another 10 were fitted with stepwise appliances with an initial advancement of 2 mm and a subsequent increase to 3.5 mm on day 30. The rats in the experimental groups were killed on days 3, 7, 14, 21, 30, 33, 37, 44, 51, and 60, respectively. The matched controls were killed on the same time points. Sections (7 microm) were cut through the glenoid fossa sagittally and stained with anti-VEGF antibody. VEGF expression in the posterior glenoid fossa was evaluated with a computer-assisted image-analyzing system. Both VEGF expression and new bone formation were greater in the experimental rats than in the controls. During stepwise advancement, initial VEGF expression was less than that of 1-step advancement, but the second advancement elicited another peak on day 44. New bone formation was also less than that of 1-step advancement during early stages of stepwise advancement but then began to increase from day 37 onward. The maximum increase was observed on day 60. Stepwise advancement of the mandible delivers mechanical stimuli that produce a series of tissue responses that lead to increased vascularization and bone formation.  相似文献   
993.
To evaluate the long-term effects of entacapone on both mean daily 'on' time and health-related quality of life (QoL) in patients with Parkinson's disease (PD) experiencing 'end-of-dose' motor fluctuations and the benefits of an early therapeutic intervention. A prospective, multicenter, observational, 12-month study was performed with an initial 3-month intervention phase, consisting of a phone call to half of the patients from randomly selected investigators to assess if dose adjustment was necessary. Effectiveness was determined by home diaries ('on' time), subscales II and III of the Unified Parkinson's Disease Rating Scale (UPDRS), and the Parkinson's Disease Questionnaire (PDQ-8). After 3 months of treatment, 4.0% of the intervention group patients discontinued the study, versus 18.4% in the control group ( P  < 0.01). The improvement in 'on' time was significantly increased since the 3-month visit (21%, P  < 0.0001) until the end of the study (23% at 12 months, P  < 0.0001). Entacapone also induced significant reductions in the UPDRS scores for subscales II and III and in the PDQ-8 score. 11.2% of patients experienced at least one adverse reaction. This study confirms the effectiveness of entacapone in reducing motor fluctuations by increasing 'on' time, and in improving QoL of PD patients. An early adjustment of entacapone and levodopa doses reduces the number of treatment discontinuations during the first months of treatment.  相似文献   
994.
995.
We describe a case of neonatal osteofibrous dysplasia that was diagnosed 3 days after birth. Osteofibrous dysplasia is a fibro-osseous lesion rarely seen in long bones. It is also known as congenital osteitis fibrosa or ossifying fibroma of bones. Although it occurs in children under 10 years of age, it is extremely rare in newborn babies. It must be differentiated from adamantinoma due to their radiological appearance, predilection for tibia and fibula, clinical picture, and certain histological similarities.  相似文献   
996.
Guidelines for design of clinical trials evaluating behavioral headache treatments were developed to facilitate production of quality research evaluating behavioral therapies for management of primary headache disorders. These guidelines were produced by a Workgroup of headache researchers under auspices of the American Headache Society. The guidelines are complementary to and modeled after guidelines for pharmacological trials published by the International Headache Society, but they address methodologic considerations unique to behavioral and other nonpharmacological treatments. Explicit guidelines for evaluating behavioral headache therapies are needed as the optimal methodology for behavioral (and other nonpharmacologic) trials necessarily differs from the preferred methodology for drug trials. In addition, trials comparing and integrating drug and behavioral therapies present methodological challenges not addressed by guidelines for pharmacologic research. These guidelines address patient selection, trial design for behavioral treatments and for comparisons across multiple treatment modalities (eg, behavioral vs pharmacologic), evaluation of results, and research ethics. Although developed specifically for behavioral therapies, the guidelines may apply to the design of clinical trials evaluating many forms of nonpharmacologic therapies for headache.  相似文献   
997.
998.
999.
1000.
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