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   34988篇
  免费   3656篇
  国内免费   83篇
耳鼻咽喉   207篇
儿科学   1137篇
妇产科学   971篇
基础医学   4937篇
口腔科学   714篇
临床医学   4229篇
内科学   6324篇
皮肤病学   557篇
神经病学   3034篇
特种医学   1494篇
外国民族医学   3篇
外科学   4434篇
综合类   775篇
一般理论   43篇
预防医学   4275篇
眼科学   885篇
药学   2622篇
中国医学   47篇
肿瘤学   2039篇
  2022年   271篇
  2021年   613篇
  2020年   328篇
  2019年   581篇
  2018年   609篇
  2017年   466篇
  2016年   521篇
  2015年   553篇
  2014年   780篇
  2013年   1157篇
  2012年   1637篇
  2011年   1608篇
  2010年   960篇
  2009年   862篇
  2008年   1473篇
  2007年   1579篇
  2006年   1542篇
  2005年   1477篇
  2004年   1439篇
  2003年   1344篇
  2002年   1279篇
  2001年   1194篇
  2000年   1206篇
  1999年   1041篇
  1998年   451篇
  1997年   412篇
  1996年   376篇
  1995年   319篇
  1994年   357篇
  1993年   340篇
  1992年   818篇
  1991年   790篇
  1990年   770篇
  1989年   684篇
  1988年   707篇
  1987年   657篇
  1986年   599篇
  1985年   667篇
  1984年   541篇
  1983年   421篇
  1982年   274篇
  1981年   292篇
  1980年   261篇
  1979年   463篇
  1978年   350篇
  1977年   263篇
  1976年   280篇
  1974年   285篇
  1973年   261篇
  1972年   268篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Soda pop vending machine tipping continues to be a dangerous behavior that can result in lethal or crippling injuries. This study analyzes 64 cases of injuries secondary to crushing by a soda machine. All were male victims except one. The average age was 19.8 years with a range of 5-39 years. Thirteen victims sustained multiple trauma. Fifteen victims were killed. Increased public awareness coupled with support by the government and private industry has contributed to a sharp reduction in incidence of accidents and improved public safety.  相似文献   
82.
1. Phospholipase A2 (PLA2) cleaves phospholipids to produce a lyso-phospholipid and free fatty acid and, in view of the biological activity of the products, PLA2 may play a role in many disease states. Lyso-phospholipids and free arachidonic acid increase in ischaemic myocardium, indicating that ischaemia activates the enzyme. 2. Plasma PLA2 activity was measured in patients with acute myocardial infarction, based on the release of labelled arachidonic acid from Escherichia coli cell membrane. Fourteen males (peak serum creatine phosphokinase (CK) above twice upper normal) were studied on day 1 (within 6 h of chest pain onset), days 2-4, and days 6-9. Normal age matched males (n = 13) were also studied. 3. Plasma PLA2 in patients with uncomplicated myocardial infarction (n = 12) was, initially, 1.14 +/- 0.10 (s.e.m.) nmol/min per mL plasma, similar to that in the normal group (1.52 +/- 0.14). On days 2-4, PLA2 activity increased to 1.94 +/- 0.18 (P less than 0.001) and this activity was correlated with the earlier peak CK level (P less than 0.02). On days 6-9, PLA2 activity was 1.49 +/- 0.13 while in two patients who developed complications and underwent open-heart surgery between the last two measurements, there were further increases to 4.22 and 4.04 nmol/min per mL. 4. The increase in plasma PLA2 in uncomplicated myocardial infarction is likely to be due to release from the damaged myocardium; whether it contributes to pathophysiology is uncertain.  相似文献   
83.
84.
Fentanyl and the interleukin-6 response to surgery   总被引:12,自引:0,他引:12  
It has been suggested that large doses of opioids may suppress the interleukin-6 response to surgery. We examined the effects of the supplementation of inhalational anaesthesia with either 3 or 15 μg.kg−1 fentanyl on the circulating interleukin-6, interleukin-8, C-reactive protein, cortisol and glucose concentrations in 16 patients undergoing pelvic surgery. In both groups, surgery evoked the expected glucose, cortisol and interleukin-6 response but no increase in interleukin-8 was detected. There were no significant differences between the two groups. We conclude that the supplementation of inhalational anaesthesia with conventional doses of opioids does not modify the cytokine response to surgery.  相似文献   
85.
Serum antibody production and induction of antibody tolerance were monitored in mice following intermittent inhalation of ovalbumin dust (mass concentration = 4.2 mg m-3; diameter of 80% of particles less than 2.6 microns). Repeated inhalation of microgram quantities of dust stimulated serum antibody production and development of tolerance. The sequence of these responses is analogous to that following oral presentation of antigen, but is produced by a much lower dose when antigen is presented via the respiratory tract.  相似文献   
86.
Summary Modifications of the assay method of Aminoff (1961) for the determination of sialic acid levels in urine, amniotic fluid, cultured cell homogenates and tissue homogenates, which reduce the interference from proteins by precipitation and from interfering chromogens by second derivative spectroscopy are described.Biochemical profiles of patients from three families with different clinical forms of sialic acid storage disease were made using data obtained with the new method. A family with two patients with the clinically severe, early-onset form is described, in which a 9-fold elevation of sialic acid can be detected in the skin fibroblasts and a 12-fold elevation in the urine. A patient from the second family is described with very severe clinical features and with 160-fold and 16-fold elevations of sialic acid in the urine and skin fibroblasts respectively. A patient from a third family is described with mild clinical features but with a 160-fold and 6-fold elevation of sialic acid in urine and skin fibroblasts respectively. The data obtained in this study are compared with data obtained in other laboratories on other patients.The method was used to assess the levels of sialic acid present in amniotic cells and chorionic villus cells obtained prenatally from pregnancies in each of the three families. In one case, in which amniotic cells were elevated in sialic acid and were vacuolated, the pregnancy was terminated. Follow-up studies confirmed the diagnosis. Pregnancies from the other two families were assessed to be not affected.  相似文献   
87.
88.
89.
Prediction of choledocholithiasis using a pocket microcomputer   总被引:4,自引:0,他引:4  
A computerized method, using a small pocket computer, has been used to predict the presence of choledocholithiasis in a prospective series of 239 patients undergoing cholecystectomy. From an initial data base of 424 patients 36 factors were evaluated and the most important 2 of these were determined by multivariate analysis for use in the prospective analysis. Satisfactory operative cholangiograms were a prerequisite to evaluation of the statistical method and were obtained in 90.4 per cent of cases. Using the computerized method a common bile duct stone would have been overlooked in only 1 patient but 17 unnecessary explorations would have been carried out. The overall accuracy of the computerized method was 92.5 per cent. When the method was applied to a further study of 97 patients from a separate centre the overall accuracy was 85.6 per cent. If the method was used to aid selective use of operative cholangiography, cholangiograms would be performed in 20 per cent and stones would be overlooked in less than 1 per cent.  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