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   5603篇
  免费   385篇
  国内免费   20篇
耳鼻咽喉   49篇
儿科学   199篇
妇产科学   164篇
基础医学   721篇
口腔科学   126篇
临床医学   531篇
内科学   883篇
皮肤病学   43篇
神经病学   765篇
特种医学   318篇
外科学   681篇
综合类   89篇
一般理论   2篇
预防医学   670篇
眼科学   46篇
药学   423篇
中国医学   2篇
肿瘤学   296篇
  2021年   63篇
  2019年   74篇
  2018年   78篇
  2017年   75篇
  2016年   73篇
  2015年   84篇
  2014年   129篇
  2013年   163篇
  2012年   237篇
  2011年   235篇
  2010年   145篇
  2009年   164篇
  2008年   237篇
  2007年   214篇
  2006年   238篇
  2005年   199篇
  2004年   195篇
  2003年   179篇
  2002年   168篇
  2001年   182篇
  2000年   170篇
  1999年   178篇
  1998年   76篇
  1997年   77篇
  1996年   97篇
  1995年   72篇
  1994年   51篇
  1993年   69篇
  1992年   111篇
  1991年   139篇
  1990年   120篇
  1989年   109篇
  1988年   105篇
  1987年   125篇
  1986年   119篇
  1985年   89篇
  1984年   61篇
  1983年   78篇
  1982年   65篇
  1981年   54篇
  1980年   48篇
  1979年   80篇
  1978年   58篇
  1977年   62篇
  1976年   51篇
  1975年   60篇
  1974年   68篇
  1973年   44篇
  1972年   39篇
  1971年   37篇
排序方式: 共有6008条查询结果,搜索用时 15 毫秒
21.
WmB. Carpenter 《Lancet》1841,36(940):843-844
  相似文献   
22.
We currently use flawed calculations to set a woman's due date based on menstrual periods to determine gestational age. We use the estimated gestational age to make management decisions based on our patients' individual needs. This principle is in contrast to our patients' use of dating to set an estimated date of confinement. This date is seen as a very specific point in time. Patients and their families plan on that date and become distressed when the expected date is not met. Given that many patients are induced electively, that many will have their delivery dates changed, and that many will have delivery dates adjusted for medical reasons, and most importantly given that dating is inaccurate and unreliable, we propose eliminating the due date. We propose giving patients a calculated assigned week of delivery at 32 weeks. An assigned week of delivery allows for individualization of obstetric care based on the needs of our patients, their support systems, and hospital staffing. We believe an assigned week of delivery will improve obstetric practice and patient satisfaction.  相似文献   
23.
24.
25.
Summary Comparisons are drawn of metabolism measurements made on a man under basal conditions, after ingestion of 30 and 50 cc., respectively, of absolute alcohol in a 250-cc. water solution, and after control doses of water and saccharin. With theBenedict helmet and opencircuit system observations were made with the subject at rest, during work (bicycle ergometer), and during recovery following work. Each experiment lasted 3 hours and comprised consecutive periods, usually of 15 minutes' duration. The work was performed immediately after or 1 hour after ingestion of the dose and lasted for 1 hour at the rate of 275 kg./m., 1/2 hour at 550 kg./m., 2 hours at 275 kg./m., or 2 hours at 415 kg./m. per minute.The metabolism of alcohol, as indicated by the course of the R. Q. and the oxygen absorption, proceeded at about the same rate irrespective of whether the subject was at rest or engaged in muscular activity. This was true in all experiments save those when the subject rested for 1 hour before beginning work after alcohol ingestion. These exceptions suggest that the period of time during which work is done after alcohol ingestion may be of effect upon the rate of alcohol combustion.The efficiency of performance of work (relation between the heat equivalent of work performed and the energy expenditure) was slightly greater in some experiments, slightly lower in others, and practically unchanged in others after alcohol ingestion.Calculation of the increments above the pre-work base-line values in R. Q., carbon-dioxide production, and oxygen consumption in the periods of work and recovery following alcohol ingestion and calculation of the changes in catabolism of carbohydrate and fat during work and recovery lead also to the conclusion that muscular work does not increase the combustion of alcohol. Comparison of the heat production of the subject when at rest and at work and after ingestion of the control and alcohol doses gives no indication of a summation of the separate effects of alcohol ingestion and muscular work when both these factors are superimposed upon the basal metabolism.Abstract presented at the 45th annual meeting of the American Physiological Society, Cincinnati, Ohio, USA., April, 1933. Amer. J. Physiol.105, 17 (1933).  相似文献   
26.
27.
28.
29.
30.
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