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   3796篇
  免费   220篇
  国内免费   29篇
耳鼻咽喉   30篇
儿科学   121篇
妇产科学   149篇
基础医学   439篇
口腔科学   97篇
临床医学   363篇
内科学   837篇
皮肤病学   89篇
神经病学   184篇
特种医学   129篇
外国民族医学   4篇
外科学   545篇
综合类   118篇
一般理论   2篇
预防医学   267篇
眼科学   100篇
药学   249篇
中国医学   27篇
肿瘤学   295篇
  2023年   52篇
  2022年   108篇
  2021年   172篇
  2020年   112篇
  2019年   122篇
  2018年   160篇
  2017年   108篇
  2016年   107篇
  2015年   120篇
  2014年   127篇
  2013年   203篇
  2012年   238篇
  2011年   250篇
  2010年   143篇
  2009年   137篇
  2008年   195篇
  2007年   193篇
  2006年   188篇
  2005年   190篇
  2004年   166篇
  2003年   132篇
  2002年   113篇
  2001年   62篇
  2000年   57篇
  1999年   46篇
  1998年   23篇
  1997年   19篇
  1996年   30篇
  1995年   21篇
  1994年   18篇
  1993年   23篇
  1992年   30篇
  1991年   27篇
  1990年   38篇
  1989年   25篇
  1988年   21篇
  1987年   28篇
  1986年   16篇
  1985年   17篇
  1984年   16篇
  1983年   15篇
  1982年   13篇
  1980年   14篇
  1979年   23篇
  1978年   14篇
  1977年   18篇
  1975年   12篇
  1974年   12篇
  1973年   18篇
  1967年   7篇
排序方式: 共有4045条查询结果,搜索用时 15 毫秒
71.
72.
73.
Graham W  Hussein J 《Lancet》2004,363(9402):67-68
  相似文献   
74.
75.
To determine whether platelet size and volume are related to one another or to platelet age, subpopulations of platelets from patients with idiopathic thrombocytopenic purpura (ITP) have been produced on the basis of density using Percoll gradients. The density distribution of platelets from patients with ITP and from patients with other forms of thrombocytopenia (thought to be nonimmune in nature) was the same as in normal controls. However, the platelets in each density subpopulation from ITP patients were increased in size. beta-thromboglobulin (beta TG) content of platelets from each patient group and the normals increased with density and tended to be higher in ITP than in normal controls. beta TG concentration per unit platelet volume and its level in plasma were similar in ITP patients and in normal controls. This suggests that the apparently normal density of ITP platelets was not a result of degranulation of large, dense platelets. Thus platelet size and density are independently determined and the increased size of platelets in immune thrombocytopenia may be the result of abnormalities in their production.  相似文献   
76.
Endometriosis is only rarely the cause of massive bloody ascites. This entity simulates gynecological malignancy and is seldom recognized before surgical exploration of the abdomen. It is more commonly seen in black nulliparous females. Hormonal modulation has obviated the need for surgical resection, in some cases. We report a case of such an entity and review the medical literature.  相似文献   
77.
AIM:To develop a novel model of colitis in rats, using a combination of iodoacetamide and enteropathogenic E. coli(EPEC), and to elucidate the pathophysiologic processes implicated in the development of ulcerative colitis (UC).
METHODS: Hale Sprague-Dawley rats (/7 = 158) were inoculated intrarectally on a weekly basis with 4 different combinations: (a) 1% methylcellulose (HC), (b) 100 μL of 6% iodoacetamide (IA) in 1% HC, (c) 200 p.L containing 4×10^8 colony factor units (CFU) of EPEC, and (d) combined treatment of (IA) followed by bacteria (13) after 2 d. Thirty days post treatment, each of the four groups was divided into two subgroups; the inoculation was stopped for one subgroup and the other subgroup continued with biweekly inoculation until the end of the experiment. Colitis was evaluated by the clinical course of the disease, the macroscopic and microscopic alterations, activity of myeloperoxidase (HPO), and by TNF-α gene expression. RESULTS: Findings indicative of UC were seen in the combined treatment (IA + B) as well as the IA continued treatment groups: the animals showed slow rate of increase in body weight, diarrhea, bloody stools, high colonic ulcer score, as well as histological alterations characteristic of UC, with an extensive inflammatory reaction. During the course of the experiment, the MPO activity was consistently elevated and the TNF-α gene expression was upregulated compared to the control animals.
CONCLUSION: The experimental ulcerative colitis model used in the present study resembles, to a great extent, the human disease. It is reproducible with characteristics indicative of chronicity.  相似文献   
78.
79.
In a prospective study, histopathological examination 298 upper gastrointestinal (UGI) biopsies, obtained from 201 consecutive patients, was made. Patients were referred with mild to severe dyspeptic symptoms. The aim of the study was to compare the rate of identification of Helicobacter pylori (H. pylori) in the histologically normal gastric mucosa with that in histologically confirmed gastritis or peptic ulcer disease. The gastroduodenal mucosa was histologically normal in 35 patients (17.4%); among those patients, H. pylori was identified in only three (9%). Chronic gastritis was histologically confirmed in 162 patients (80.6%). H. pylori was identified in 123 (76%) of those patients. The difference was statistically significant (p less than 0.00001). Furthermore, when cases with a histological diagnosis of superficial chronic active gastritis (SCAG) are considered separately, the identification rate of H. pylori increases to 88% (121 of 137). When this rate is compared with that of 8% (two of 25), found in superficial chronic quiescent gastritis (SCQG), the difference is highly significant (p less than 0.00001). Of 38 endoscopically diagnosed peptic ulcers, H. pylori was identified in the gastric mucosa of 34 (89%). The organisms were always seen in the antral gastric mucosa, but never in duodenal mucosa. Identification of H. pylori correlates significantly with the histologic activity of chronic gastritis, in both peptic ulcer disease and non-ulcer dyspepsia.  相似文献   
80.
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