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   5523篇
  免费   246篇
  国内免费   30篇
耳鼻咽喉   173篇
儿科学   284篇
妇产科学   242篇
基础医学   414篇
口腔科学   219篇
临床医学   508篇
内科学   1233篇
皮肤病学   186篇
神经病学   298篇
特种医学   209篇
外科学   1267篇
综合类   68篇
预防医学   119篇
眼科学   135篇
药学   183篇
中国医学   8篇
肿瘤学   253篇
  2023年   46篇
  2022年   83篇
  2021年   131篇
  2020年   91篇
  2019年   117篇
  2018年   162篇
  2017年   136篇
  2016年   195篇
  2015年   199篇
  2014年   220篇
  2013年   344篇
  2012年   431篇
  2011年   420篇
  2010年   245篇
  2009年   186篇
  2008年   376篇
  2007年   416篇
  2006年   361篇
  2005年   379篇
  2004年   313篇
  2003年   258篇
  2002年   223篇
  2001年   104篇
  2000年   77篇
  1999年   63篇
  1998年   26篇
  1997年   16篇
  1996年   17篇
  1995年   7篇
  1994年   12篇
  1993年   11篇
  1992年   16篇
  1991年   12篇
  1990年   11篇
  1989年   8篇
  1988年   10篇
  1987年   10篇
  1986年   6篇
  1985年   7篇
  1984年   7篇
  1982年   3篇
  1980年   3篇
  1979年   5篇
  1974年   3篇
  1971年   2篇
  1970年   3篇
  1969年   3篇
  1967年   6篇
  1966年   3篇
  1909年   2篇
排序方式: 共有5799条查询结果,搜索用时 15 毫秒
41.
The mineral content of 43 honey samples from the middle regions of Turkey was investigated. Minerals were determined by inductively coupled plasma-atomic emission spectrophotometer. Calcium, potassium, sodium and phosphorus were the most abundant of the elements in all the studied honeys, with average concentrations ranging between 40.13 and 189.69 mg/kg for calcium, 161.01 and 598.62 mg/kg for potassium, 9.34 and 45.9 mg/kg for sodium, and 460.11 and 3,776.96 mg/kg for phosphorus. Cluster analysis of the honey data revealed that the mineral content of Çorum and Konya honeys was closer as they formed a cluster at a similarity level of 60%.  相似文献   
42.
BackgroundEmerging evidence suggests that sex steroid hormones may influence respiratory symptoms. The existing literature about the role of oral contraceptive pill (OCP) on respiratory disease is scarce and conflicting especially during the adolescent period. In this study, we aimed to investigate the effect of OCPs on current wheezing among adolescents and young adults.MethodsA questionnaire was administered face-to-face to adolescents and young women by a physician. The questionnaire included ISAAC survey-comprised questions on ever wheezing, current wheezing, allergic diseases, smoking history (active or passive), and family history of allergic diseases and questions on OCP usage status. The effect of OCPs on wheezing was evaluated by logistic regression analysis.ResultsA total of 487 subjects aged between 11.3 and 25.6 years participated in the study and 196 (40.2%) reported that they had used OCPs. 7.4% of the participants had physician-diagnosed asthma and 10.3% of them were active smokers. It was detected that OCPs were associated with increased risk for current wheezing (odds ratio, 2.36; 95% CI, 1.25–4.47 adjusted for asthma and current smoker) and this risk was related with the usage during the past year.ConclusionYoung women taking oral contraceptives had a higher rate of current wheezing, suggesting that sex steroids may be of importance for respiratory health.  相似文献   
43.
44.
45.
46.
47.
Inflammatory bowel disease has been linked to elevated T cells. Excessive production of reactive oxygen species and apoptosis are known to be accompanied by intestinal inflammation. This study was designed to investigate the effects of melatonin (MEL) and erythropoietin (EPO), which is a known anti‐inflammatory and antiapoptotic agent, in dinitrobenzene sulfonic acid (DNBS)–induced colitis in pinealectomized (Px) rats. In microscopically results, epithelial and goblet cell loss, absence of crypts, and increased colonic caspase‐3 activity were observed in the DNBS group. Also, in flow cytometric analysis, the percentage of CD4+ T cells was highest in the DNBS group. Treatment with MEL or EPO had a curative effect on DNBS‐induced colitis. The MEL + EPO groups showed significantly greater improvement when compared with the other treatment groups. Our results indicate that the combination of EPO and MEL may exert more beneficial effects than either agent used alone.  相似文献   
48.
49.
Thalidomide is shown to be an effective treatment for mucocutaneous symptoms of Behcet's disease (BD). In this study, the effects of thalidomide on peripheral blood mononuclear cells were investigated ex vivo. In an open prospective study, ten patients were given 200 mg/day thalidomide for 12 weeks and cluster of differentiation 4 (CD4), CD8, CD11a, CD11b, CD16, CD18, CD28, CD44, CD45RO, CD45RA, CD56, CD120a and γδ+ T cells were analysed with flow cytometry at 0, 3, 7, 30 and 90 days. Two patients were excluded from the analysis for attacks of uveitis within the first 2 weeks. At day 7, tumour necrosis factor-α (TNF-α) receptor+ (CD120a; 12% vs 5%), CD8/CD11b+ (12% vs 6%) and CD16/CD56+ (16% vs 9%) cells decreased in BD patients compared to day 0. On the other hand, CD4+CD45RO+ T cells (24% vs 34%) at day 30 and γδ+ T cells (11% vs 21%) at day 90 increased after treatment. These results suggest that thalidomide tends to decrease TNF-α receptor levels, CD8/CD11b+ T cells and natural killer cells in early treatment and increases CD4+CD45RO+ memory T and γδ+ T cells later in BD.  相似文献   
50.
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