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   949473篇
  免费   65620篇
  国内免费   2481篇
耳鼻咽喉   13071篇
儿科学   29763篇
妇产科学   26923篇
基础医学   132992篇
口腔科学   25376篇
临床医学   79374篇
内科学   194965篇
皮肤病学   19475篇
神经病学   76224篇
特种医学   38382篇
外国民族医学   336篇
外科学   149993篇
综合类   19572篇
一般理论   311篇
预防医学   68045篇
眼科学   20942篇
药学   66748篇
中国医学   1843篇
肿瘤学   53239篇
  2019年   7587篇
  2018年   10580篇
  2017年   8206篇
  2016年   8787篇
  2015年   10053篇
  2014年   14366篇
  2013年   21514篇
  2012年   29623篇
  2011年   31204篇
  2010年   18793篇
  2009年   17763篇
  2008年   29589篇
  2007年   31276篇
  2006年   31380篇
  2005年   30860篇
  2004年   29347篇
  2003年   28275篇
  2002年   27605篇
  2001年   41671篇
  2000年   42772篇
  1999年   36597篇
  1998年   10432篇
  1997年   9549篇
  1996年   9412篇
  1995年   8752篇
  1994年   8308篇
  1993年   7810篇
  1992年   28359篇
  1991年   27133篇
  1990年   26556篇
  1989年   25474篇
  1988年   23665篇
  1987年   23281篇
  1986年   22352篇
  1985年   21272篇
  1984年   15934篇
  1983年   13591篇
  1982年   8220篇
  1979年   14651篇
  1978年   10282篇
  1977年   8690篇
  1976年   8203篇
  1975年   9009篇
  1974年   10750篇
  1973年   10232篇
  1972年   9686篇
  1971年   8948篇
  1970年   8617篇
  1969年   8050篇
  1968年   7714篇
排序方式: 共有10000条查询结果,搜索用时 8 毫秒
991.
Renal cell carcinomas may extend into the vena cava and the tumor thrombus occasionally involves the right atrium. The operative approach depends upon precise preoperative and intraoperative staging and thrombus localization. We report a case of renal cell carcinoma with complete inferior vena caval and hepatic vein occlusion with tumor extension into the right atrium. Preoperatively, transesophageal echocardiography provided superior images of the tumor and its extension, and intraoperatively allowed continuous monitoring of cardiac function and the removal of tumor from the atrium and inferior vena cava. Its use obviated the need for more costly and invasive preoperative and intraoperative procedures.  相似文献   
992.
We examine and refine the Fagerström Tolerance Questionnaire (FTQ; Fagerström, 1978). The relation between each FTQ item and biochemical measures of heaviness of smoking was examined in 254 smokers. We found that the nicotine rating item and the inhalation item were unrelated to any of our biochemical measures and these two items were primary contributors to psychometric deficiencies in the FTQ. We also found that a revised scoring of time to the first cigarette of the day (TTF) and number of cigarettes smoked per day (CPD) improved the scale. We present a revision of the FTQ: the Fagerström Test for Nicotine Dependence (FTND).  相似文献   
993.
Patients with mood depression have been found to have a higher prevalence of seborrheic dermatitis (SD), possibly related to their tendency to live indoors. The prevalence of outpatients with SD has now been found to be directly related to the number of gloomy days in the area. Since UV light might not be the only reason for the well-known improvement in SD in summer, an explanation possibly related to melatonin is envisaged.  相似文献   
994.
995.
Twenty patients with sympathetic maintained pain (SMP) underwent surgery to treat an associated nerve injury. In each patient, an axillary catheter technique was used to maintain anesthesia and sympatholysis for up to 4 days following surgery. In no instance was the SMP exacerbated by the operation. The use of prolonged sympathetic blockade as an adjunct increases the margin of safety in surgery for these patients when nonoperative measures cannot relieve the pain or restore function.  相似文献   
996.
997.
During a 3-year period Branhamella catarrhalis was isolated in significant numbers from 239 (1.3%) of 19,488 specimens of sputum sent for routine microbiological examination at a 700-bed general hospital. The majority of patients (83%) were over 60 years of age and 65% were male. There was a distinct seasonal variation in isolations with a peak incidence during the winter and early spring, a pattern not found with other pathogens. Susceptibility to amoxycillin decreased by approximately 50% over the 3 years, corresponding to an increased incidence of beta-lactamase-producing strains. There were minimal changes in susceptibility to other antimicrobial agents. Underlying pulmonary disease was the major factor predisposing to B. catarrhalis infection, and 71% of patients were smokers or ex-smokers.  相似文献   
998.
ABSTRACT— One hundred and fifty-four patients with histologically verified nonalcoholic chronic liver disease were randomized to azathioprine or prednisone treatment. After a median of 91 months observation time, the cause of death was assessed retrospectively. Autopsy was performed in 82% of 71 deaths. In the azathioprine group 33% (13/39) died from malignant neoplasia, and in the prednisone group (13%) (4/32) (p = 0.08). Considering a possible fatal outcome as a consequence of treatment, this finding urges caution in the long-term application of azathioprine at the usual dose level.  相似文献   
999.
To determine the relationship between severity of illness and mortality, therapeutic intervention score (TISS) and acute physiology score (APS) were determined on admission to the Surgical Intensive Care Unit (SICU). Patients were divided into survivors and nonsurvivors and differences were compared by chi-square analysis. The 1524 patients admitted to the SICU during a 12-month period had a mean TISS of 3.03 and a mean APS of 13. The average length of stay (LOS) was 3.75 days. Of the 1524 patients, 97 (6.4%) died. The number of nonsurvivors increased with higher TISS and APS scores (P less than 0.001). There were no deaths in the TISS Category 1 patients or in the APS 0-5 group. Mortality rates dramatically increased with APS greater than 20 (P less than 0.001). There were 1286 patients with APS less than 20, and 24 (2%) of these patients died, whereas 73 (31%) of 238 patients with APS greater than 20 died. Nonsurvivors had a mean TISS of 3.6, mean APS of 27, and LOS of 4.88 days, all of which totals were higher than the survivors' totals. In this study population, risk of death was one in three if the APS was greater than 20. These data indicate that TISS and APS scores are effective means of assessing mortality risk in SICU patients.  相似文献   
1000.
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