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   1465392篇
  免费   117471篇
  国内免费   5057篇
耳鼻咽喉   19131篇
儿科学   47533篇
妇产科学   42835篇
基础医学   207716篇
口腔科学   38671篇
临床医学   132027篇
内科学   294355篇
皮肤病学   34364篇
神经病学   120187篇
特种医学   56053篇
外国民族医学   470篇
外科学   217465篇
综合类   36700篇
现状与发展   10篇
一般理论   497篇
预防医学   113066篇
眼科学   32732篇
药学   103209篇
  22篇
中国医学   4946篇
肿瘤学   85931篇
  2021年   12879篇
  2019年   13150篇
  2018年   18378篇
  2017年   14052篇
  2016年   15716篇
  2015年   18157篇
  2014年   25206篇
  2013年   36507篇
  2012年   49792篇
  2011年   52242篇
  2010年   30904篇
  2009年   29457篇
  2008年   47547篇
  2007年   50028篇
  2006年   50413篇
  2005年   48649篇
  2004年   46297篇
  2003年   44125篇
  2002年   42304篇
  2001年   74086篇
  2000年   75380篇
  1999年   62327篇
  1998年   17428篇
  1997年   15793篇
  1996年   15916篇
  1995年   15083篇
  1994年   13680篇
  1993年   12754篇
  1992年   46187篇
  1991年   43771篇
  1990年   41777篇
  1989年   39819篇
  1988年   36427篇
  1987年   35600篇
  1986年   33081篇
  1985年   31470篇
  1984年   23985篇
  1983年   20150篇
  1982年   12279篇
  1981年   10858篇
  1979年   20838篇
  1978年   14682篇
  1977年   12147篇
  1976年   11433篇
  1975年   11675篇
  1974年   14046篇
  1973年   13583篇
  1972年   12686篇
  1971年   11509篇
  1970年   10945篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
992.
Inflammatory abnormalities may be involved in the inadequate basal oxidant/antioxidant balance and local exercise-induced oxidative stress in chronic obstructive pulmonary disease (COPD) patients. The time course of oxidative stress and inflammation was investigated in 10 COPD patients and seven healthy subjects before and after local dynamic quadriceps endurance exercise at 40% of maximal strength. Venous samples were collected before, immediately after and up to 48 h after exercise. At rest, levels of an oxidant released by stimulated phagocytes, the superoxide anion, were significantly higher in patients, as were plasma levels of C-reactive protein, tumour necrosis factor-alpha and interleukin-6, inflammatory markers. An inverse relationship was found between baseline C-reactive protein levels and endurance time in patients. Six hours after exercise, superoxide anion release and levels of protein oxidation products, an index of oxidative stress, increased similarly in both groups, whereas thiobarbituric acid reactive substance levels, another index of oxidative stress, increased significantly only in patients. Plasma nonenzymatic antioxidant and inflammatory cytokine levels were unchanged by the exercise protocol. The increased baseline systemic inflammation in chronic obstructive pulmonary disease patients could be related to disturbed oxidant/antioxidant balance, and, together, these may have triggered the exercise-induced oxidative stress. The absence, however, of local exercise-induced systemic inflammation suggests that additional mechanisms explain local exercise-induced oxidative stress.  相似文献   
993.
Abstract – Aim: To evaluate the pulp and periodontal healing of laterally luxated permanent teeth. Material and methods: Patients presenting with lateral luxation of permanent teeth during 2001–2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root‐canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re‐examinations were performed after 1, 2, 3, 6, 12 and 48 months. Results: All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root‐canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4‐year re‐examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. Conclusions: Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices.  相似文献   
994.
995.
996.
THE ELECTRO-CAUTERY IN THE TREATMENT OF GLAUCOMA   总被引:2,自引:2,他引:0  
  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