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   741969篇
  免费   50515篇
  国内免费   1480篇
耳鼻咽喉   9811篇
儿科学   23892篇
妇产科学   18261篇
基础医学   115122篇
口腔科学   21037篇
临床医学   66279篇
内科学   142780篇
皮肤病学   16656篇
神经病学   52465篇
特种医学   26910篇
外国民族医学   76篇
外科学   110565篇
综合类   14973篇
现状与发展   2篇
一般理论   162篇
预防医学   52739篇
眼科学   16892篇
药学   57000篇
  3篇
中国医学   2432篇
肿瘤学   45907篇
  2021年   6111篇
  2019年   5902篇
  2018年   8420篇
  2017年   6533篇
  2016年   7349篇
  2015年   8122篇
  2014年   11006篇
  2013年   16363篇
  2012年   22079篇
  2011年   23187篇
  2010年   13694篇
  2009年   12756篇
  2008年   21597篇
  2007年   23279篇
  2006年   23607篇
  2005年   22112篇
  2004年   21612篇
  2003年   20604篇
  2002年   20080篇
  2001年   37545篇
  2000年   38211篇
  1999年   31524篇
  1998年   8297篇
  1997年   7012篇
  1996年   7282篇
  1995年   6897篇
  1994年   6345篇
  1992年   23800篇
  1991年   23658篇
  1990年   23013篇
  1989年   22825篇
  1988年   20704篇
  1987年   20067篇
  1986年   19110篇
  1985年   17908篇
  1984年   13120篇
  1983年   11096篇
  1982年   6097篇
  1979年   11915篇
  1978年   8363篇
  1977年   7055篇
  1976年   6716篇
  1975年   7447篇
  1974年   8697篇
  1973年   8332篇
  1972年   7841篇
  1971年   7331篇
  1970年   7059篇
  1969年   6518篇
  1968年   5968篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
81.
Detection of non-palpable early splenic enlargement may aid diagnosis of primary polycythaemia (PP) and primary thrombocythaemia (PT). In this study linear spleen sizing by ultrasound has been compared with spleen volume estimation by single photon emission computerized tomography (SPECT) in 26 patients. Spleen length by ultrasound correlated well with SPECT volume estimation.
Ultrasound spleen length was also measured in 60 normal control subjects where the upper limit of the 95% reference range was 11.6 cm. Changes in spleen length with both age and body weight were substantial and overshadowed the imperfect reproducibility of this method. Therefore, interpretation of an individual's measured spleen length should be in relation to that predicted for adults of the same age and weight, particularly at the extremes of the younger, heavier patients and also the older, lighter patients.
Ultrasound spleen lengths of different patient groups (21 PP, 26 PT, 17 idiopathic erythrocytosis, 12 secondary polycythaemia, nine apparent polycythaemia) were compared both using the measured overall reference range and the differences from the values predicted for their age and weight. The comparison showed that almost all patients with PP whose spleens were not palpable had spleen lengths greater than the upper limit for the normal control group, but separation from the other patient groups was incomplete.
Detection of non-palpable splenomegaly by ultrasound length should remain a 'minor' criterion amongst the 'proposed modified diagnostic criteria' of PP.  相似文献   
82.
83.
84.
85.
86.
Selective protection of the normal host tissues from the toxic effects of anticancer agents would allow the use of higher, probably more effective, doses of the drugs. It has been demonstrated that delayed high-dose uridine administration after 5-fluorouracil decreases the extent of myelosuppression and causes faster regeneration of the bone marrow. We studied the biochemical consequences of the gastrointestinal toxicity caused by 5-fluorouracil and the potential of high-dose uridine treatment to influence these adverse effects. 5-Fluorouracil caused dose-related decreases in the biochemical parameters (thymidine kinase, sucrase, maltase, alkaline phosphatase) selected as early markers of the impaired metabolic activity of the intestinal mucosa. The nadir of the biochemical changes was reached between 24 h and 72 h after 5-fluorouracil treatment, and complete regeneration of the mucosa took 6–7 days. Delayed high-dose uridine administration failed to mitigate the severity of the gastrointestinal damage that ensued after 5-fluorouracil treatment, but caused significantly earlier regeneration of the mucosa.  相似文献   
87.
In 82 CHD male patients aged 35-54 years with well-preserved working capacity (threshold load, 600-750 kgm/min) who had underwent bicycle ergometer test, the time course of changes in the major hemodynamic parameters was found to be significantly similar to that of healthy individuals. The cases who stopped performing bicycle ergometer tests because of anginal attacks, and ST segment depression or either showed a more significant elevation in systolic and diastolic blood pressure at the maximum load rate and lower increase in heart rate than in healthy subjects, which may be regarded as a compensatory mechanism that prevents a further decrease in coronary flow. Diminished increase in stroke index and cardiac index suggests reduced myocardial contractility.  相似文献   
88.
89.
Eighty-nine cases of chronic bronchitis were matched against167 asymptomatic controls from the glass bangle industry ofFirozabad. Factors of age, social status, smoking habit andduration of exposure were studied. Duration of exposure wasfound to be a factor contributing significantly to the causationof disease. Requests for reprints should be addressed to: Dr B. N. Gupta, Division of Epidemilogy, Industrial Toxicology Research Centre, Mahatma Gandhi Marg, Lucknow P.O. Box 80, 226001, India  相似文献   
90.
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