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   26800篇
  免费   1333篇
  国内免费   151篇
耳鼻咽喉   274篇
儿科学   559篇
妇产科学   626篇
基础医学   3409篇
口腔科学   1040篇
临床医学   1941篇
内科学   7206篇
皮肤病学   702篇
神经病学   2028篇
特种医学   502篇
外科学   4347篇
综合类   175篇
一般理论   3篇
预防医学   1938篇
眼科学   444篇
药学   1476篇
中国医学   122篇
肿瘤学   1492篇
  2023年   208篇
  2022年   438篇
  2021年   962篇
  2020年   438篇
  2019年   892篇
  2018年   1025篇
  2017年   574篇
  2016年   588篇
  2015年   756篇
  2014年   1101篇
  2013年   1385篇
  2012年   2197篇
  2011年   2240篇
  2010年   1326篇
  2009年   1144篇
  2008年   1806篇
  2007年   1863篇
  2006年   1717篇
  2005年   1527篇
  2004年   1418篇
  2003年   1348篇
  2002年   1240篇
  2001年   159篇
  2000年   130篇
  1999年   170篇
  1998年   192篇
  1997年   148篇
  1996年   146篇
  1995年   124篇
  1994年   100篇
  1993年   84篇
  1992年   73篇
  1991年   55篇
  1990年   51篇
  1989年   41篇
  1988年   46篇
  1987年   35篇
  1986年   22篇
  1985年   39篇
  1984年   36篇
  1983年   40篇
  1982年   46篇
  1981年   45篇
  1980年   44篇
  1979年   18篇
  1978年   26篇
  1977年   27篇
  1975年   22篇
  1974年   21篇
  1973年   19篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
62.
We studied fixation changes over time in 113 porous-coated Howmedica (PCA) cementless acetabular cups inserted in 90 patients 1984-1988. The mean follow-up was 5 years. Radiographic fixation was classified as stable, fibrous-stable, or unstable. 9 cups, 3 in neutral position and 6 vertical, were revised. At follow-up, 40/75 neutral cups were stable versus 7/27 vertical cups. Most stable cups and two thirds of the unstable cups were clinically good. After the first 2 years, 28/75 neutral cups and 10/27 vertical cups changed their fixation: 12 had improved fixation and 26 had a worse one.  相似文献   
63.
Eminent surgeons who received the Nobel Prize in Physiology or Medicine for their work and accomplishments are considered Nobel Laureate surgeons. There are nine such distinguished individuals who achieved this award. In chronological order, from earliest to latest, we encounter: 1. Theodor Kocher, 1909, thyroid gland pathology; 2. Allvar Gullstrand, 1911, dioptrics of the eye; 3. Alexis Carrel, 1912, vascular suture and organ transplant; 4. Robert Barany, 1914, vestibular system; 5. Frederick Banting, 1923, discovery of insulin; 6. Walter Hess, 1949, midbrain function; 7. Werner Forssmannn, 1956, cardiac catheterization; 8. Charles Huggins, 1966, hormones and cancer; 9. Joseph Murray, 1990, organ transplantation. These extraordinary Nobel Laureate surgeons had in common four significant qualities expressed by four letters, CDFI, representing commitment, determination, focus, and innovation. The examples of a sustained path of accomplishment and success set by these unique personalities serve as a vivid guide for future generations of surgeons.  相似文献   
64.
OBJECTIVE: The objective of the present study was to investigate whether or not the presence of irregular bleeding during use of oral contraceptives (OC) is associated with increased cyclooxygenase-2 (COX-2) expression. PATIENTS AND METHODS: An observational study was carried out in 26 patients who were using gestodene 75 microg/ethinylestradiol 30 microg prior to endometrial resection. The patients were divided into two groups: those with amenorrhea (n = 14) and those who had irregular bleeding (n = 12). The resected endometrium was immunostained for COX-2, Bcl-2 and Ki-67 expression. Routine pathology was carried out using standard hematoxylin-eosin staining. RESULTS: Irregular bleeding during OC use was associated with strong COX-2 expression in both glandular and superficial epithelium. There were also more patients in this group with irregular endometrial maturation and higher Ki-67 values. Bcl-2 expression, on the other hand, was not affected by the presence of uterine bleeding. CONCLUSION: The presence of irregular bleeding during OC use is associated with strong COX-2 expression in the endometrium, thereby suggesting a pivotal role of prostaglandins in this process.  相似文献   
65.
66.
T cells are known to develop a critical role in the pathogenesis of atopic dermatitis (AD) and bronchial asthma. T cells involved in AD express the skin homing receptor CLA, but no lung homing receptor has been identified in bronchial asthma. We compared different cell markers and the cytokine production in T cells from children with AD or bronchial asthma. We studied the involvement of CLA+ and CLA- T-cell subpopulations in these diseases. We studied 20 children with acute AD lesions, 15 with mild persistent asthma, and 15 non-atopic controls. All patients were sensitized to house dust mite (DP) and evaluated during the acute phase. Total and specific IgE were measured by immunoassay and the expression of different cell markers and the cytokine production was analyzed by flow cytometry in peripheral blood mononuclear cells. Total IgE was significantly higher in AD children and IgE to DP in the asthmatic children. There was a significant increase in CD25+ CD4+ cells in asthmatic children and in HLA-DR+ CD4+ and HLA-DR+ CD8+ cells in AD. In the CD4+ subsets, there was an increase in IL-13, IL-5 and TNF-alpha in AD compared to controls, a decrease in IFN-gamma in asthmatic children compared to controls, and an increase in IL-13, IL5, IL2, TNF-alpha, and IFN-gamma in the AD compared to asthmatic children. Changes in cytokine production were mainly detected in CLA+ cells in AD and in CLA- cells in asthma. Differences exist in total and specific IgE, activation markers, and cytokine patterns between AD children and children with asthma, with the former expressing a Th2 pattern whereas in asthmatic children we only detected a decrease in IFN-gamma. Moreover, the subpopulations (CLA+ vs. CLA-) expressing these changes were different, indicating that the underlying mechanisms in the two diseases are not exactly the same.  相似文献   
67.
68.
69.
INTRODUCTION: The management of children receiving small bowel grafts involves potentially life-threatening complications that affect their nutritional status. The aim of this paper was to define these factors and their influence on nutritional outcome. PATIENTS AND METHODS: Patients with intestinal failure (IF) who received an isolated small bowel transplantation (SBT) or small bowel/liver transplantation (SBLT) at our hospital during the last 6 years were reviewed for weight Z-score, biochemical nutritional parameters, total parenteral nutrition (TPN) weaning, catheter-related sepsis, rejection and steroid treatment. RESULTS: Twenty patients, 11 females and 9 males, received a SBT or a SBLT and survived the postoperative period; in the present study we only included 11 children with follow-up periods longer than 1 year. Seven males and 4 females with a mean age of 4.5 years (range, 1 to 20 years) received 6 SBLT and 5 SBT. Nine (82%) were weaned from TPN to an amino-acid or peptide enteral formula during the first 6 months after surgery. During the first year there was a significant increase in total protein from 5.11 +/- 1.8 mg/dl to 6.1 +/- 1.5 mg/dl (p < 0.05) and an increase in albumin from 3.8 +/- 0.9 mg/dl to 4.5 +/- 1.1 mg/dl (p < 0.05). There was an increase in weight Z-score in 9 patients (82%) during the first year. Mean Z-score improved from - 2.6 +/- 1 at transplant to - 1.0 +/- 0.6 (p < 0.05) after 1 year. Three patients (27.2%) had at least one rejection period, which was treated with steroids alone or in combination. Mean weight Z-score 1 year after surgery was - 0.9 +/- 0.6 for patients without rejection and - 1.24 +/- 0.8 for those with at least one rejection episode treated with steroids (p > 0.1). Four patients (36%) had at least one catheter-related sepsis episode. Mean weight Z-score 1 year after surgery was - 1.01 +/- 0.6 for patients without catheter-related sepsis and - 1.24 +/- 0.8 for those with at least one catheter-related sepsis episode (p > 0.1). CONCLUSIONS: There was a significant improvement in weight Z-score and biochemical nutritional parameters 1 year after receiving a small bowel graft. No influence of steroids or catheter-related sepsis on children's nutritional status was noted 1 year after surgery, although this point will need further evaluation.  相似文献   
70.

Objectives  

This study was designed to assess the prevalence of adverse drug reactions (ADRs) in the internal medicine wards of two teaching Hospitals, identify the most common ADRs, the principal medications involved, and determine the risk factors implicated in the occurrence of such ADRs.  相似文献   
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