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   1800760篇
  免费   130670篇
  国内免费   4136篇
耳鼻咽喉   23183篇
儿科学   58441篇
妇产科学   47828篇
基础医学   254765篇
口腔科学   50852篇
临床医学   162149篇
内科学   355193篇
皮肤病学   40305篇
神经病学   141445篇
特种医学   67477篇
外国民族医学   246篇
外科学   272364篇
综合类   40668篇
现状与发展   5篇
一般理论   692篇
预防医学   133973篇
眼科学   42670篇
药学   131059篇
  9篇
中国医学   4633篇
肿瘤学   107609篇
  2021年   14448篇
  2019年   15189篇
  2018年   21852篇
  2017年   16658篇
  2016年   18269篇
  2015年   20967篇
  2014年   29104篇
  2013年   42484篇
  2012年   59169篇
  2011年   62385篇
  2010年   36697篇
  2009年   34471篇
  2008年   58210篇
  2007年   61985篇
  2006年   62280篇
  2005年   59834篇
  2004年   57687篇
  2003年   54957篇
  2002年   52853篇
  2001年   92778篇
  2000年   94395篇
  1999年   78015篇
  1998年   21195篇
  1997年   18482篇
  1996年   18395篇
  1995年   17729篇
  1994年   16093篇
  1993年   14907篇
  1992年   57995篇
  1991年   55846篇
  1990年   53546篇
  1989年   51285篇
  1988年   46623篇
  1987年   45407篇
  1986年   42701篇
  1985年   40569篇
  1984年   30072篇
  1983年   25619篇
  1982年   14923篇
  1981年   13310篇
  1979年   25944篇
  1978年   18078篇
  1977年   15402篇
  1976年   14263篇
  1975年   14923篇
  1974年   17946篇
  1973年   17210篇
  1972年   15865篇
  1971年   14572篇
  1970年   13557篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
An empirical investigation of the perceived role of robotics and artificial computer intelligence in the future of health care reveals factors favoring a positive attitude by health administrators. The study employed a two-part survey administered in late 1989 and early 1990 to health care managers in hospitals and nursing homes. Part One of the survey asked about the participant, his or her work habits and work environment. Part Two obtained a psychological profile of rationality vs. intuition in problem solving. Through bivariate and multivariate post hoc statistical tests, we discovered the following variables which significantly determined attitudes toward robotics and artificial computer intelligence: sex, number of employees supervised; perceptions of waste and inefficiency in the workplace; perceptions of time-consuming personnel problem; perceived need to make more efficient use of time, money, and facilities; and perceived favorable climate for innovation. Among the factors which did not have an effect on attitudes toward advanced technology were three measures of rationality vs. intuition in problem solving.  相似文献   
992.
Several studies have reported that the heart is severely affected by chronic malnutrition. However, the influence of these alterations on cardiac function remains unclear. The aim of this study was to evaluate the effects of subacute starvation on the heart chronotropic response to a beta-adrenergic agonist (isoproterenol). Twelve rats were fed rat chow ad libitum or a 50%-restricted diet for 17 days. The rats were killed, the right atrium was isolated and incubated, and in vitro spontaneous cardiac contractions and frequency were registered. Cumulative doses of isoproterenol were added to the solution until maximal cardiac frequency was achieved. A deficit of 25% in the weight gain was observed in study rats compared with controls (92.6 +/- 10.2 vs. 113.8 +/- 19.2 g, p less than 0.05). Mean daily food intake was 4.8 +/- 0.1 and 9.8 +/- 0.5 g/day for semistarved and control rats, respectively. The in vitro cardiac frequency of the semistarved rats was similar to that of controls (290 +/- 15 and 305 +/- 23 beats/min, respectively, NS). However, when isoproterenol was added to the solution, maximal cardiac frequency of the semistarved rats (435 +/- 51 beats/min) was lower than that of control rats (508 +/- 34 beats/min, p less than 0.005). These findings suggest that subacute starvation may alter the cardiac response to beta-adrenergic agonists.  相似文献   
993.
994.
Growth plate: roentgenologic findings in a case of tyrosinosis   总被引:1,自引:0,他引:1  
S Morrison  D Kerr 《Pediatrics》1989,83(4):599-600
  相似文献   
995.
996.
997.
998.
999.
A monoclonal antibody (MoAb, SK-930) of the IgG2a subclass to human pancreatic carcinoma cells (MIA-PaCa 2) was obtained by hybridization of spleen cells from immunized Balb/c mice with murine myeloma cells. SK-930 was investigated for reacting in indirect immunofluorescence on FACS against a panel comprising 12 types of different origin. SK-930 reacted with seven out of 11 tumor cells and with one PBL. Immunoperoxidase techniques (ABC method) showed that SK-930 antigen was present on pancreatic adenocarcinoma cells, but could not be detected on normal pancreatic tissue. Immunoprecipitation experiments and SDS-PAGE analysis revealed that SK-930 recognized 134K dalton peptide on tumor cells. These results suggest that SK-930 reacts with a novel pancreatic cancer-associated antigen.  相似文献   
1000.
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