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   903614篇
  免费   62736篇
  国内免费   2353篇
耳鼻咽喉   12530篇
儿科学   28820篇
妇产科学   26240篇
基础医学   127099篇
口腔科学   24814篇
临床医学   75101篇
内科学   184073篇
皮肤病学   19033篇
神经病学   71779篇
特种医学   36523篇
外国民族医学   337篇
外科学   142523篇
综合类   19057篇
一般理论   249篇
预防医学   64951篇
眼科学   20142篇
药学   64209篇
中国医学   1806篇
肿瘤学   49417篇
  2018年   9170篇
  2017年   7255篇
  2016年   7789篇
  2015年   8835篇
  2014年   12529篇
  2013年   19434篇
  2012年   25958篇
  2011年   27550篇
  2010年   16728篇
  2009年   15946篇
  2008年   26394篇
  2007年   27976篇
  2006年   28136篇
  2005年   27664篇
  2004年   26502篇
  2003年   25630篇
  2002年   25215篇
  2001年   41418篇
  2000年   42602篇
  1999年   36317篇
  1998年   10008篇
  1997年   9179篇
  1996年   9101篇
  1995年   8461篇
  1994年   8104篇
  1993年   7607篇
  1992年   28228篇
  1991年   27004篇
  1990年   26432篇
  1989年   25366篇
  1988年   23568篇
  1987年   23187篇
  1986年   22260篇
  1985年   21170篇
  1984年   15823篇
  1983年   13483篇
  1982年   8097篇
  1979年   14609篇
  1978年   10217篇
  1977年   8633篇
  1976年   8158篇
  1975年   8970篇
  1974年   10707篇
  1973年   10192篇
  1972年   9670篇
  1971年   8925篇
  1970年   8589篇
  1969年   8034篇
  1968年   7688篇
  1967年   7090篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
There are no data available combining transbronchial needle aspiration (TBNA) of mediastinal lymph nodes and positron emission tomography (PET) in the staging of nonsmall cell lung cancer (NSCLC). The aim of the current study was to determine if these two methods can enhance the negative predictive value of the individual modality alone, for a specific lymph node station, and if this integrated approach can reduce the number of mediastinoscopies. A total of 113 patients with enlarged mediastinal lymph nodes (> or = 1 cm), who underwent both TBNA and PET scanning, were included. In 51 patients, histopathology, confirmed by surgical lymph node dissection, was compared with PET results and TBNA. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy to detect malignant lymphadenopathy was 68 (13/19), 89 (119/134), 46 (13/28), 95 (119/125) and 86% (132/152) for PET, respectively; 54% (6/11), 100 (53/53), 100 (6/6), 91 (53/58) and 92% (59/64), respectively for TBNA; and 100 (11/11), 94 (50/53), 79 (11/14), 100 (50/50) and 95 (61/64) for combined TBNA and PET, respectively. Combination of transbronchial needle aspiration and positron emission tomography has the potential to allow adequate mediastinal staging of nonsmall cell lung cancer with enlarged lymph nodes in most patients without the need for mediastinoscopy.  相似文献   
42.
43.
44.
45.
46.
47.
48.
To examine the prevalence of Internet sex networking among men who have sex with men (MSM) in Hong Kong and risk behaviors associated with the behavior, a telephone survey of 15,230 Hong Kong Chinese men aged 18-60 was conducted. Of the 283 active MSM (having engaged in some MSM behaviors in the last 6 months) identified, 17.7% had networked for MSM partners via the Internet in the last 6 months. Younger age (odds ratio [OR] for age < or = 25 vs. age >25 = 4.67, 95% confidence interval [CI] = 2.35-9.28) and being an anal-sex MSM (OR = 4.72, 95% CI=2.36-9.44) were independent predictors of Internet sex networking. Being an Internet sex networker was associated with some risk behaviors such as having contracted a sexually transmitted disease (adjusted OR = 4.79, 95% CI = 1.34-17.11), having had > or = 3 MSM partners (adjusted OR = 4.74, 95% CI = 2.20-10.23), and having engaged in anal sex (adjusted OR = 3.95, 95% CI = 1.89-8.23). HIV prevention programs for MSM should thereby include Internet-based interventions.  相似文献   
49.
50.
Atherosclerotic renal artery stenosis (ARAS) may cause hypertension, progressive renal failure, and recurrent pulmonary edema. It typically occurs in high risk patients with coexistent vascular disease elsewhere. Most patients with ARAS are likely to die from coronary heart disease or stroke before end-stage renal failure occurs. Recent controlled trials have shown that most patients undergoing angioplasty to treat renovascular hypertension still need antihypertensive agents 6 or 12 months after the procedure. Nevertheless, the number of antihypertensive agents required to control blood pressure adequately is lower following angioplasty than for medication alone. Trials assessing the value of revascularization for preserving renal function or preventing clinical events are only in the early recruitment phase. Revascularization should be undertaken in patients with ARAS and resistant hypertension or heart failure, and probably in those with rapidly deteriorating renal function or with an increase in plasma creatinine levels during angiotensin-converting enzyme inhibition. With or without revascularization, medical therapy using antihypertensive, hypolipidemic and antiplatelet agents is necessary in almost all cases.  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