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   900220篇
  免费   62485篇
  国内免费   2335篇
耳鼻咽喉   12475篇
儿科学   28685篇
妇产科学   26147篇
基础医学   126674篇
口腔科学   24688篇
临床医学   74844篇
内科学   183237篇
皮肤病学   18987篇
神经病学   71488篇
特种医学   36467篇
外国民族医学   336篇
外科学   142152篇
综合类   19038篇
一般理论   247篇
预防医学   64678篇
眼科学   20098篇
药学   63823篇
中国医学   1798篇
肿瘤学   49178篇
  2018年   9067篇
  2017年   7172篇
  2016年   7681篇
  2015年   8736篇
  2014年   12383篇
  2013年   19233篇
  2012年   25691篇
  2011年   27290篇
  2010年   16598篇
  2009年   15804篇
  2008年   26155篇
  2007年   27762篇
  2006年   27972篇
  2005年   27477篇
  2004年   26324篇
  2003年   25496篇
  2002年   25084篇
  2001年   41378篇
  2000年   42572篇
  1999年   36286篇
  1998年   9976篇
  1997年   9162篇
  1996年   9093篇
  1995年   8453篇
  1994年   8090篇
  1993年   7587篇
  1992年   28210篇
  1991年   26990篇
  1990年   26428篇
  1989年   25356篇
  1988年   23562篇
  1987年   23179篇
  1986年   22252篇
  1985年   21157篇
  1984年   15808篇
  1983年   13477篇
  1982年   8089篇
  1979年   14591篇
  1978年   10209篇
  1977年   8627篇
  1976年   8147篇
  1975年   8960篇
  1974年   10697篇
  1973年   10183篇
  1972年   9661篇
  1971年   8918篇
  1970年   8584篇
  1969年   8026篇
  1968年   7685篇
  1967年   7087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.
Priori  A.  Cogiamanian  F.  Mrakic-Sposta  S. 《Neurological sciences》2006,27(4):s307-s309
Neurological Sciences - Spasticity arises from lesions involving the corticoreticulospinal system in the brain, brainstem or spinal cord. Abnormal suprasegmental influences lead to increased spinal...  相似文献   
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