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   1002392篇
  免费   69688篇
  国内免费   2499篇
耳鼻咽喉   13307篇
儿科学   31447篇
妇产科学   28249篇
基础医学   142616篇
口腔科学   27444篇
临床医学   83624篇
内科学   203561篇
皮肤病学   20766篇
神经病学   81549篇
特种医学   40598篇
外国民族医学   345篇
外科学   154715篇
综合类   19490篇
现状与发展   1篇
一般理论   343篇
预防医学   76498篇
眼科学   21809篇
药学   69901篇
  12篇
中国医学   1998篇
肿瘤学   56306篇
  2019年   8106篇
  2018年   11170篇
  2017年   8930篇
  2016年   9645篇
  2015年   10924篇
  2014年   15434篇
  2013年   23208篇
  2012年   31749篇
  2011年   33428篇
  2010年   19783篇
  2009年   19134篇
  2008年   31526篇
  2007年   33378篇
  2006年   33307篇
  2005年   32492篇
  2004年   30619篇
  2003年   29598篇
  2002年   28817篇
  2001年   44669篇
  2000年   45796篇
  1999年   39184篇
  1998年   11214篇
  1997年   10193篇
  1996年   10180篇
  1995年   9335篇
  1994年   8944篇
  1993年   8355篇
  1992年   30244篇
  1991年   28815篇
  1990年   28126篇
  1989年   26988篇
  1988年   25063篇
  1987年   24501篇
  1986年   23494篇
  1985年   22343篇
  1984年   16709篇
  1983年   14253篇
  1982年   8500篇
  1979年   15284篇
  1978年   10629篇
  1977年   8983篇
  1976年   8413篇
  1975年   9242篇
  1974年   11026篇
  1973年   10530篇
  1972年   9968篇
  1971年   9228篇
  1970年   8807篇
  1969年   8254篇
  1968年   7941篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
Adverse ocular effects associated with niacin therapy.   总被引:2,自引:0,他引:2       下载免费PDF全文
In a retrospective survey of patients taking medication for hyperlipidaemia, those taking niacin (nicotinic acid) were more likely (p < 0.05) to report sicca syndromes, blurred vision, eyelid oedema, and macular oedema compared with those who never took niacin. Additionally, 7% of those taking niacin discontinued the drug owing to adverse ocular side effects, while none of the other lipid lowering agents were found to cause these side effects (p = 0.016). Data from spontaneous reporting systems support a possible association of decreased vision, cystoid macular oedema, sicca-like symptoms, discoloration of the eyelids with or without periorbital or eyelid oedema, proptosis, loss of eyebrow or eyelashes, and superficial punctate keratitis with the use of niacin in high doses. Decreased vision may be marked, and if the drug is not discontinued, may progress to cystoid macular oedema. All ocular side effects listed above are reversible if the association with niacin is recognised and the drug is discontinued; both the incidence and severity of the ocular side effects seem to be dose dependent.  相似文献   
72.
73.
Of 431 patients with gastric cancer observed in our institution, 23 (5.3%) had early gastric cancer (EGC). Macroscopic presentation, histology, depth of invasion, and lymph node involvement were evaluated in all the cases. All patients underwent surgery and an intensive follow-up was performed. Five of the 23 patients progressed, and the risk factors were examined. Histology seemed to be the main prognostic factor in our study, since intestinal type of EGC was associated to a significantly better prognosis. Total gastrectomy is indicated in the proximal localization of EGC, and should perhaps be performed also in cases presenting undifferentiated histology.  相似文献   
74.
Premalignant lesions of the penis include cutaneous horn, balanitis xerotica obliterans, and leukoplakia. The true incidence of progression of each of these to squamous-cell carcinoma is unknown. Bowenoid papulosis, erythroplasia of Queyrat, and Bowen's disease are histologically identical to in situ carcinoma. Although the first is consistently benign, the latter two regularly evolve into invasive cancer. Malignant scrotal lesions include squamous-cell carcinoma, liposarcoma, leiomyosarcoma, basal-cell carcinoma, extramammary Paget's disease, erythroplasia of Queyrat, malignant melanoma, and metastases. Hemangioma can be confused with carcinoma.  相似文献   
75.
76.
77.
Fetal B lymphocytes in mice and humans use a limited number of the available VH gene segments. Mouse fetal B cells primarily utilize 3' VH elements, suggesting that the localization of these elements determines their rearrangement frequency. The previously reported non-random usage of human VH genes has been more difficult to explain. In this study the authors analysed the expression of the most proximal 3' human VH element (VH6) using a monoclonal antibody (JE-6). VH6 expression was assessed in various B cell differentiation stages from fetal liver, bone marrow and spleen at 12–20 weeks of gestation. The authors demonstrate that the level of VH6 expression does not exceed a stochastic usage frequency. This suggests that the localization of VH6 does not significantly promote its expression during human fetal life, and that other factors must affect the usage of VH genes during human fetal development.  相似文献   
78.
79.
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