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   2448623篇
  免费   178031篇
  国内免费   6475篇
耳鼻咽喉   34299篇
儿科学   77229篇
妇产科学   68947篇
基础医学   352069篇
口腔科学   70403篇
临床医学   223594篇
内科学   472335篇
皮肤病学   52304篇
神经病学   199963篇
特种医学   92978篇
外国民族医学   782篇
外科学   359707篇
综合类   54882篇
现状与发展   7篇
一般理论   870篇
预防医学   191072篇
眼科学   56550篇
药学   183655篇
  8篇
中国医学   5556篇
肿瘤学   135919篇
  2018年   25454篇
  2017年   19757篇
  2016年   21535篇
  2015年   24556篇
  2014年   34105篇
  2013年   52648篇
  2012年   70819篇
  2011年   75011篇
  2010年   44116篇
  2009年   41552篇
  2008年   70330篇
  2007年   75436篇
  2006年   75898篇
  2005年   73482篇
  2004年   70701篇
  2003年   67865篇
  2002年   66326篇
  2001年   111565篇
  2000年   115045篇
  1999年   97218篇
  1998年   26901篇
  1997年   24476篇
  1996年   23812篇
  1995年   22511篇
  1994年   21077篇
  1993年   19653篇
  1992年   76504篇
  1991年   74581篇
  1990年   72904篇
  1989年   70187篇
  1988年   65200篇
  1987年   63967篇
  1986年   61251篇
  1985年   58266篇
  1984年   43637篇
  1983年   37302篇
  1982年   22402篇
  1981年   20120篇
  1979年   41060篇
  1978年   29344篇
  1977年   24780篇
  1976年   23351篇
  1975年   25325篇
  1974年   30430篇
  1973年   29675篇
  1972年   28024篇
  1971年   26104篇
  1970年   24570篇
  1969年   23032篇
  1968年   21809篇
排序方式: 共有10000条查询结果,搜索用时 484 毫秒
911.
912.
913.
914.
OBJECTIVES: Specific information addressing the management of cerebrospinal fluid (CSF) fistulas that originate from within the sphenoid sinus remains scant. The objective of this study was to review the cause and management of CSF rhinorrhea arising from the sphenoid sinus. STUDY DESIGN AND SETTING: This is a retrospective chart review of 12 cases of CSF rhinorrhea arising from the sphenoid sinus that occurred in 11 patients. All patients were treated at a single institution between 1994 and 1999. RESULTS: All patients were managed surgically with sphenoid sinus fat obliteration using an endoscopic sublabial, transseptal approach. This approach was successful for all 12 cases, with median duration of follow-up of 18 months. CONCLUSIONS: Endoscopically assisted transseptal repair of CSF fistulas that originate within the sphenoid sinus offers an alternate approach to previously described methods of repair in this region. Advantages include wide access to the entire sphenoid sinus, improved access to laterally pneumatized regions within the sphenoid sinus, and rostral mucosal closure over the repair within the sinus.  相似文献   
915.
In der Behandlung von Frakturen spielt die Analgesie eine wesentliche Rolle. Es stellt sich daher die Frage, ob in der Klinik h?ufig eingesetzte Analgetika wie Tramadol oder Diclofenac negative Wirkungen auf die Knochenbruchheilung haben.  相似文献   
916.
Background : Methimazole, an anti-thyroid drug, was recently found to be useful in the treatment of systemic lupus erythematosus and other autoimmune diseases. Moreover, decreased thyroid hormone production is associated with a variety of immunological manifestations, such as reduced activation of CD4+ cells, increased CD8+ cell activity and reduced soluble IL-2 receptors. In the present study we examined the effects of methimazole and propylthiouracil on a rat model of experimental colitis.
Methods : Colitis was induced by intracolonic administration of 30 mg trinitrobenzene sulphonic acid (TNB). Two weeks prior to induction of colitis, rats were treated by either methimaziole (0.04%) or propylthiouracil (0.01%) in drinking water after a week of free access to water. Rats were sacrificed 48 h or 7 days after induction of colitis. The colon was isolated, rinsed with ice-cold water and weighed. Damage was assessed both macroscopically and microscopically and myeloperoxidase (MPO) activity determined.
Results : All treated rats were hypothyroid as manifested by a significant elevation of thyroid stimulating hormone (TSH), by comparison with the control groups (mean -1.82±0.40 versus 0.11±0.02 mmol/L, respectively). The inflammatory response elicited by TNB resulted in severe mucosal damage 48 h after damage induction, which persisted for 7 days. Pre-treatment with either methimazole 0.04% or propylthiouracil 0.01% significantly decreased mucosal damage macroscopically (lesion area, lesion score and segmental weight) microscopically and also significantly decreased MPO level at both time points ( P <0.01).
Conclusions : Methimazole and propylthiouracil significantly reduce mucosal damage and colonic weight in a rat model of colitis. The mode by which they do so remains to be studied.  相似文献   
917.
高效液相色谱法测定人血浆中阿莫西林浓度及药代动力学   总被引:6,自引:0,他引:6  
谭力  周继红  罗楠  袁倚盛 《药学学报》1997,32(7):558-560
高效液相色谱法测定人血浆中阿莫西林浓度及药代动力学谭力周继红罗楠袁倚盛(南京军区南京总医院中心仪器分析科,南京210001)阿莫西林(amoxicilin)为β内酰胺类抗生素,其抗菌谱广,口服受食物影响小,对大多数病人耐受性良好,因而在临床上得以广泛...  相似文献   
918.
Aims Objective of this study was to investigate whether adenosine modulates renal erythropoietin production.
Methods In the present study erythropoietin production was stimulated by hypobaric hypoxia by subjecting healthy volunteers to a simulated altitude of 4000  m in a low pressure chamber for 5.5  h. During exposure to hypoxia the subjects received i.v. in a randomized, single-blind, cross-over fashion the non-specific adenosine antagonist theophylline, the adenosine reuptake inhibitor dipyridamole and placebo.
Results Contrary to the working hypothesis, theophylline did not decrease and dipyridamole did not further boost erythropoietin concentrations.
Conclusions The results are in agreement with our earlier study using haemorrhage as a controlled physiological stimulus of erythropoietin production, and would question a major role for adenosine as a mediator of renal erythropoietin production.  相似文献   
919.
920.
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