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   3464023篇
  免费   308159篇
  国内免费   15605篇
耳鼻咽喉   47544篇
儿科学   109368篇
妇产科学   87767篇
基础医学   550571篇
口腔科学   93573篇
临床医学   315481篇
内科学   613437篇
皮肤病学   89744篇
神经病学   297528篇
特种医学   139093篇
外国民族医学   299篇
外科学   536147篇
综合类   113643篇
现状与发展   31篇
一般理论   2264篇
预防医学   296253篇
眼科学   78941篇
药学   240500篇
  53篇
中国医学   12113篇
肿瘤学   163437篇
  2021年   56059篇
  2020年   35967篇
  2019年   58481篇
  2018年   71784篇
  2017年   54999篇
  2016年   60449篇
  2015年   75045篇
  2014年   109706篇
  2013年   175179篇
  2012年   94445篇
  2011年   94417篇
  2010年   118877篇
  2009年   123192篇
  2008年   81176篇
  2007年   84109篇
  2006年   94541篇
  2005年   89656篇
  2004年   91186篇
  2003年   81971篇
  2002年   71004篇
  2001年   111545篇
  2000年   105081篇
  1999年   102304篇
  1998年   66191篇
  1997年   63818篇
  1996年   62015篇
  1995年   57755篇
  1994年   51767篇
  1993年   48363篇
  1992年   73471篇
  1991年   70197篇
  1990年   66519篇
  1989年   65093篇
  1988年   60354篇
  1987年   59034篇
  1986年   55853篇
  1985年   55955篇
  1984年   50404篇
  1983年   45746篇
  1982年   42543篇
  1981年   39964篇
  1980年   37664篇
  1979年   41755篇
  1978年   36554篇
  1977年   33110篇
  1976年   30449篇
  1975年   29025篇
  1974年   30259篇
  1973年   29025篇
  1972年   27026篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
This paper presents an analysis of samples from 75 patients for the presence of rubella virus, viral RNA, and specific antibodies. For all samples, RNA detection was higher than virus isolation. It was found that it was not possible to isolate rubella virus in every sixth clinical sample containing the viral RNA. Primary structures of the site (from the 8072nd to 8291st nucleotide) of the rubella virus genome from 14 samples were determined. This paper shows that all the samples of rubella virus belong to the first genotype, subgroups 1h, and very likely to subgroups 1a and 1F. For the first time, the circulation of rubella virus of the genotype has been shown both prior to the start of mass vaccination in Western Siberia and after.  相似文献   
992.
993.
994.
Nickel is the leading cause of allergic contact dermatitis (ACD) from early childhood through adolescence. Studies have shown that skin piercings and other nickel‐laden exposures can trigger the onset of nickel ACD in those who are susceptible. Nickel ACD causes a vast amount of cutaneous disease in children. Cases of nickel ACD in children have been reported in peer‐reviewed literature from 28 states. Common items that contain inciting nickel include jewelry, coins, zippers, belts, tools, toys, chair studs, cases for cell phones and tablets, and dental appliances. The diagnosis of nickel ACD has been routinely confirmed by patch testing in children older than 6 months suspected of ACD from nickel. Unlike in Europe, there are no mandatory restrictions legislated for nickel exposure in the United States. Denmark has demonstrated that regulation of the nickel content in metals can lower the risk of ACD and the associated health care–related costs that arise from excess nickel exposure. To further awareness, this article reviews the prominent role of nickel in pediatric skin disease in the United States. It discusses the need for a campaign by caretakers to reduce nickel‐related morbidity. Lastly, it promotes the model of European legislation as a successful intervention in the prevention of nickel ACD.  相似文献   
995.
A 3‐year‐old Arab boy with a history of hypoplastic left heart syndrome was referred to the pediatric dermatology clinic at Sheba Medical Center for evaluation of hypomelanosis, manifested by fair skin pigmentation and silvery‐grey hair, eyebrows, and eyelashes. The child had one older brother with similar hypopigmentation and another older brother who had died of congenital heart disease. The child had no history of neurologic deficits or immunodeficiency and no additional findings on clinical evaluation.  相似文献   
996.
997.
998.
999.
1000.
Fluid is usually restricted during thoracic surgery, and vasoactive agents are often administered to maintain blood pressure. One-lung ventilation (OLV) decreases arterial oxygenation; thus oxygen delivery to the brain can be decreased. In this study, we compared phenylephrine and dopamine with respect to maintaining cerebral oxygenation during OLV in major thoracic surgery.Sixty-three patients undergoing lobectomies were randomly assigned to the dopamine (D) or phenylephrine (P) group. The patients’ mean arterial pressure was maintained within 20% of baseline by a continuous infusion of dopamine or phenylephrine. Maintenance fluid was kept at 5 mL/kg/h. The depth of anesthesia was maintained with desflurane 1MAC and remifentanil infusion under bispectral index guidance. Regional cerebral oxygen saturation (rScO2) and hemodynamic variables were recorded using near-infrared spectroscopy and esophageal cardiac Doppler.The rScO2 was higher in the D group than the P group during OLV (OLV 60 min: 71 ± 6% vs 63 ± 12%; P = 0.03). The number of patients whose rScO2 dropped more than 20% from baseline was 0 and 6 in the D and P groups, respectively (P = 0.02). The D group showed higher cardiac output, but lower mean arterial pressure than the P group (4.7 ± 1.0 vs 3.9 ± 1.2 L/min; 76.7 ± 8.1 vs 84.5 ± 7.5 mm Hg; P = 0.02, P = 0.02). Among the variables, age, hemoglobin concentration, and cardiac output were associated with rScO2 by correlation analysis.Dopamine was superior to phenylephrine in maintaining cerebral oxygenation during OLV in thoracic surgery.  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