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   3417765篇
  免费   244128篇
  国内免费   10823篇
耳鼻咽喉   45586篇
儿科学   112189篇
妇产科学   94448篇
基础医学   484027篇
口腔科学   94333篇
临床医学   320040篇
内科学   665410篇
皮肤病学   78087篇
神经病学   283109篇
特种医学   129041篇
外国民族医学   1047篇
外科学   499401篇
综合类   71987篇
现状与发展   6篇
一般理论   1343篇
预防医学   272557篇
眼科学   76552篇
药学   250041篇
  12篇
中国医学   7485篇
肿瘤学   186015篇
  2019年   27656篇
  2018年   38865篇
  2017年   29649篇
  2016年   33899篇
  2015年   38284篇
  2014年   52761篇
  2013年   80408篇
  2012年   107495篇
  2011年   113796篇
  2010年   68254篇
  2009年   64662篇
  2008年   105756篇
  2007年   111970篇
  2006年   113639篇
  2005年   109073篇
  2004年   104644篇
  2003年   100891篇
  2002年   97524篇
  2001年   159177篇
  2000年   163398篇
  1999年   137950篇
  1998年   40255篇
  1997年   35759篇
  1996年   35757篇
  1995年   34507篇
  1994年   31854篇
  1993年   29960篇
  1992年   108307篇
  1991年   104732篇
  1990年   101553篇
  1989年   97725篇
  1988年   89771篇
  1987年   88041篇
  1986年   83025篇
  1985年   79331篇
  1984年   59331篇
  1983年   50647篇
  1982年   30173篇
  1981年   26903篇
  1979年   52948篇
  1978年   37601篇
  1977年   31532篇
  1976年   29784篇
  1975年   31365篇
  1974年   37424篇
  1973年   35830篇
  1972年   33481篇
  1971年   31152篇
  1970年   28837篇
  1969年   27302篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
981.
982.
Norfloxacin, a new quinolinecarboxylic acid derivative, was administered to 30 male patients with gonococcal urethritis at a daily dose of 600 mg for 7-21 days. The clinical response was evaluated after administration of 7 days as excellent; Negative culture of N. gonorrhoeae. WBC less than 3/hpf in first voided urine sediment, good; Negative culture, WBC greater than or equal to 3/hpf, and poor; Positive culture. The result was excellent in 14 cases and good in 16 cases. No subjective side effects were observed. The minimum inhibitory concentration (MIC) distribution against the clinically isolated 30 strains of N. gonorrhoeae ranged from 0.0096 micrograms/ml to 0.34 micrograms/ml. Seven of thirty strains were resistant to ABPC. The MIC of these 7 strains ranged from 0.018 micrograms/ml to 0.18 micrograms/ml. Seven cases with ABPC resistant strains had a similar clinical response to other cases. Twelve patients (40%) developed post gonococcal urethritis for 7-14 days after treatment. Clinical observation of this series suggests that a 7 day therapy of Norfloxacin for the patients with gonococcal urethritis is sufficiently effective and that treatment should be changed to other antibacterial agents in the case of post gonococcal urethritis, since continuous administration for more than 7 days of Norfloxacin is not so effective.  相似文献   
983.
Repeated testing attenuates conditioned place preference with cocaine   总被引:2,自引:2,他引:0  
Cocaine-treated rats acquired a preference for cocaine-associated contextual stimuli (CS) relative to saline-injected control rats. However, when animals were given repeated tests for conditioned place preference intermittent between conditioning trials, they displayed an attenuation in strength of conditioning. This attenuation was not due to pharmacologic tolerance (Experiment 1), but rather reflected a disruption in learning due to exposure to the CS alone (Experiment 2). Like other examples of classical conditioning, the strength of the conditioned response (CR) as assessed by the conditioned place preference model may be influenced by partial reinforcement.  相似文献   
984.
This study investigated social interactions between infants and mothers, comparing dyads with physically disabled infants and dyads with nondisabled infants. The groups were matched on mental and motor development, sex, socioeconomic status, birth order, and maternal education. Each infant-mother dyad was videotaped at home during a 10-minute period of free play, and blind observers subsequently transcribed infants' and mothers' behaviors. In general, the groups were remarkably similar in their interaction patterns. However, a few differences emerged: Mothers of infants with physical disabilities were significantly more commanding than were comparison mothers. Nondisabled infants tended to engage in more eye contact than did infants with physical disabilities. And whereas mothers of nondisabled infants responded to interactive play with interactive play, mothers of infants with physical handicaps tended to respond with commands and verbalizations. These results suggest reciprocal influences between infants and mothers in both groups and highlight emerging maternal behavior patterns that may interfere with the development of communication and independence in handicapped young children.  相似文献   
985.
Forty patients suffering from asthmatic conditions, often accompanied by emphysema, were treated either with an extempore combination of salbutamol syrup plus 30-mg oxatomide tablets or with 30-mg oxatomide tablets alone for purposes of comparison. Greater efficacy was obtained with the combination, which produced positive results in terms of improved respiratory status, remission of clinical symptoms and reduced anti-asthma drug requirements in 90% of the cases treated, as against only 55% of satisfactory results obtained with oxatomide alone. The combination was very well tolerated with no incidence of adverse reactions, while the treatment with oxatomide alone, though on the whole well tolerated, gave rise to mild drowsiness in four cases.  相似文献   
986.
987.
Western transfer and immunoenzymatic staining with affinity-purified monospecific antiserum was used to detect a 38-Kd protein that bound to native and denatured DNA cellulose. This protein has previously been shown to be a delayed early herpes simplex virus type-2 specific protein.  相似文献   
988.
989.
Wheat germ agglutinin (WGA) was found to stimulate DNA synthesis in human peripheral blood mononuclear cells at relatively low concentrations and to inhibit DNA synthesis at higher concentrations. Both actions were inhibited by oligomers of N-acetyl-D-glucosamine. Significant mitogenic activity was dependent on the use of human (as opposed to fetal calf) serum to supplement the culture medium. Purified T cells responded to WGA very weakly and the incorporation of thymidine into non-T cells in response to WGA was less than the lectin-free control. The full ability of T cells to respond to WGA was restored by the addition of monocytes, but not by any other blood cells. Interleukin 2 partially restored the ability of T cells to respond to WGA; interleukin 1 was less effective. WGA displayed a strong synergistic action with the tumour promoter, 12-O-tetradecanoyl-13-acetate (TPA), in stimulating DNA synthesis in separated T (but not non-T) cell fractions, and in unfractioned mononuclear cells. These results reconcile most of the conflicting reports in the literature concerning the interaction of WGA with human lymphocytes.  相似文献   
990.
A cohort of 1163 pregnant women in two small towns in South Wales, UK, was identified and followed until the children born to them were five years of age. Growth in these children is described and a number of determinants identified. Social-class differences were very small at birth but differences in height became clear by the age of two years and in head circumference before this. In height the differences were largely accounted for by greater growth in social class I, but there was a gradient in head circumference throughout all the social classes. The social class effects gradually increased as the children became older. Parity of the mothers had a small effect on size at birth but age of the mother had no effect once parity was allowed for. Data on illnesses in the children were collected but no effect on growth could be detected. By far the most important determinant of growth which could be controlled is maternal smoking. About 40% of the women smoked, about 17% heavily (15 or more cigarettes per day) and the prevalence of smoking altered little during pregnancy. There was a graded effect of smoking on growth up to a 9% deficit in birth-weight, a 2% deficit in length at birth and a 1.5% deficit in head circumference in the babies born to the mothers who smoked most heavily (25 or more cigarettes per day) compared with non-smokers. There effects decreased with age but there were still residual effects at age five years.  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