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   2064654篇
  免费   156194篇
  国内免费   3920篇
耳鼻咽喉   27286篇
儿科学   69284篇
妇产科学   58200篇
基础医学   304446篇
口腔科学   58246篇
临床医学   191326篇
内科学   399266篇
皮肤病学   45674篇
神经病学   165377篇
特种医学   77959篇
外国民族医学   554篇
外科学   299342篇
综合类   46186篇
现状与发展   3篇
一般理论   919篇
预防医学   168672篇
眼科学   47080篇
药学   150469篇
  9篇
中国医学   3784篇
肿瘤学   110686篇
  2018年   21850篇
  2017年   16821篇
  2016年   18756篇
  2015年   21455篇
  2014年   29586篇
  2013年   45407篇
  2012年   60808篇
  2011年   64946篇
  2010年   38127篇
  2009年   36320篇
  2008年   60901篇
  2007年   65031篇
  2006年   65017篇
  2005年   63113篇
  2004年   61085篇
  2003年   58656篇
  2002年   56768篇
  2001年   91891篇
  2000年   94042篇
  1999年   79178篇
  1998年   22486篇
  1997年   20433篇
  1996年   20738篇
  1995年   19790篇
  1994年   18397篇
  1993年   17184篇
  1992年   63458篇
  1991年   62306篇
  1990年   60985篇
  1989年   58921篇
  1988年   54074篇
  1987年   53738篇
  1986年   50800篇
  1985年   48494篇
  1984年   36783篇
  1983年   31689篇
  1982年   18951篇
  1981年   17148篇
  1979年   34597篇
  1978年   25288篇
  1977年   21228篇
  1976年   19913篇
  1975年   21233篇
  1974年   25818篇
  1973年   25160篇
  1972年   23627篇
  1971年   21988篇
  1970年   20616篇
  1969年   19352篇
  1968年   17995篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
991.
Changes in the height, weight, body mass index, triceps skinfold, and arm and estimated midarm muscle circumferences in lower socioeconomic Mexican American children, 6 through 17 years of age, from Brownsville, Texas, were documented on the basis of surveys done in 1972 and 1983. With the exception of height in youths ages 14-17, all parameters show gains at most ages, and in particular an increase in fatness. Brownsville Mexican American youth are similar in height, weight, and the body mass index to Mexican American youth in other areas of Texas. These trends confirm the large proportion of relatively short but heavy children among Mexican Americans.  相似文献   
992.
993.
Two hundred twenty-one first-year medical students participated in a voluntary coronary heart disease risk factor self-change project designed to teach the principles of behavioral change. Blood pressure, serum lipids, percentage body fat, cardiovascular fitness, and smoking status were measured prior to the project. Students designed their own programs of behavior modification and, after 8 weeks, repeat measurements were obtained in students whose projects related to coronary heart disease risk (56% of entire group). Despite generally low initial coronary heart disease risk factors, most risk factor groups successfully altered the targeted risk factors. The subgroup attempting to lower serum cholesterol (n = 49) reduced total cholesterol 15 +/- 24 mg/dl (mean +/- SD) and low-density lipoprotein cholesterol 11 +/- 20 mg/dl (P less than 0.001 for both). The blood pressure group (n = 9) decreased systolic blood pressure 8 +/- 10 mm Hg (P less than 0.05), and the weight-loss group (n = 33) lost 3.0 +/- 2.9 kg (P less than 0.001), reducing estimated percentage body fat 1.7 +/- 1.8 (P less than 0.001). The self-change project was well received by the students and appears to be a useful technique for introducing the principles of behavioral medicine to first-year medical students.  相似文献   
994.
995.
In 1983, 1623 primary and secondary schoolchildren took part in a health survey which was organized by the Busselton Population Studies Group. Age, sex, weight, height and country of birth were recorded for each child. Where possible, the country of birth of parents and the occupation of the father were extracted from previous Busselton surveys of adults. Compared with Perth schoolchildren, the difference in the attained weight and height of Busselton children at any age was small. This was so even though the two communities differ in location (rural compared with metropolitan), in ethnic origin (mainly British compared with diverse origins) and, probably, in social-rank distribution. Data from the two communities showed that a similar small secular increase in height had occurred since 1970/1971. This increase averaged at 1.2 cm for children at each year of age in Busselton and 1.5 cm to 1.6 cm for children in Perth.  相似文献   
996.
These researchers investigated the effects of a progressive resistive, cycle ergometric exercise program on cardio-vascular endurance in one rheumatoid arthritic. The 46 yr. old, male subject exercised three days/week for 14 weeks. Workouts included interval-type training using 5 minute intervals for a total of 20-30 minutes (work rate set at 50-75 watts for each interval), not including 3-minute warm-up and cool-down periods (work rate set at zero resistance). Maximal exercise stress testing on the cycle ergometer was completed and blood samples collected before and after the exercise program. Also, psychological and physical health and lifestyle data were gathered before, during and after completion of the program. The conditioning program produced a training effect (greater than 75% of the HR max after the second exercise session) and blood values improved (10-28%) from the beginning to the end of the program. Finally, the program appeared to have a positive influence on various physical and psychological parameters as perceived by the subject and his wife.  相似文献   
997.
998.
Previous studies of giant axonal neuropathy have reported clinical and pathological findings that indicate involvement of the central nervous system. We studied 3 boys with giant axonal neuropathy, who were 14 to 16 years of age, using auditory, visual, and somatosensory evoked potentials. Absence of waveforms and prolongation of peak and interwave latencies were found. Abnormalities were noted in all modalities. The auditory brainstem evoked response in particular indicated a significant increase in brainstem conduction time. These studies add clinical neurophysiological confirmation of the central nervous system involvement in this disorder and may also provide a means of quantitative evaluation of its progression.  相似文献   
999.
1000.
Traumatic infarction of the spinal cord in children   总被引:2,自引:0,他引:2  
Infarction of the spinal cord in childhood is rarely due to trauma. During a 15-year period (1971 to 1985), eight children were admitted to The Hospital for Sick Children, Toronto, with a diagnosis of traumatic infarction of the spinal cord. All of these patients had delayed onset of neurological signs varying between 2 hours and 4 days after their initial trauma. No bone abnormalities were seen on plain spine x-ray films. Myelography was carried out in seven of these children and found to be normal in all seven. Six patients who were paraplegic at the time of admission remained permanently paraplegic, but two with incomplete cord signs did show some improvement.  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