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   1392558篇
  免费   89653篇
  国内免费   1784篇
耳鼻咽喉   18820篇
儿科学   39312篇
妇产科学   34503篇
基础医学   211940篇
口腔科学   39209篇
临床医学   122517篇
内科学   265457篇
皮肤病学   29718篇
神经病学   101832篇
特种医学   54238篇
外国民族医学   130篇
外科学   220343篇
综合类   24833篇
现状与发展   2篇
一般理论   332篇
预防医学   95787篇
眼科学   31827篇
药学   108051篇
  4篇
中国医学   3136篇
肿瘤学   82004篇
  2018年   13802篇
  2017年   10454篇
  2016年   11800篇
  2015年   13330篇
  2014年   18118篇
  2013年   26639篇
  2012年   37474篇
  2011年   40079篇
  2010年   23499篇
  2009年   21935篇
  2008年   38214篇
  2007年   40810篇
  2006年   41159篇
  2005年   39444篇
  2004年   38304篇
  2003年   36877篇
  2002年   36006篇
  2001年   73272篇
  2000年   75585篇
  1999年   62774篇
  1998年   15239篇
  1997年   13254篇
  1996年   13332篇
  1995年   12476篇
  1994年   11393篇
  1993年   10678篇
  1992年   47698篇
  1991年   47351篇
  1990年   46321篇
  1989年   45209篇
  1988年   41325篇
  1987年   40535篇
  1986年   37722篇
  1985年   36097篇
  1984年   26040篇
  1983年   22139篇
  1982年   11436篇
  1979年   23690篇
  1978年   16236篇
  1977年   13596篇
  1976年   12768篇
  1975年   14593篇
  1974年   17142篇
  1973年   16271篇
  1972年   15325篇
  1971年   14575篇
  1970年   13798篇
  1969年   12901篇
  1968年   11940篇
  1967年   10723篇
排序方式: 共有10000条查询结果,搜索用时 0 毫秒
101.
Cerebral function in normoxia and its reactions to standard periods of hypoxia of increasing severity were studied in 30 newborn guinea pigs less than 3 days old. Intrauterine growth retardation was induced either by uterine artery ligation at midgestation or by feeding the female in late gestation with khat leaves, an amphetamine-like stimulant chewed by men and women in several countries in eastern Africa and Arabia. After spontaneous delivery, the neonates were anesthetized and ventilated. Cardiovascular, metabolic, and neurophysiologic (somatosensory evoked potentials) parameters were monitored. Under normoxia, the khat-exposed group showed prolonged latency of the primary response of the somatosensory evoked potentials and a reduced amount of secondary components. Under hypoxia, this group also has a greater reduction of amplitude of the somatosensory evoked potentials. It is concluded that khat exposure during fetal life has an impact on the cerebral function during the neonatal period (at least up to 3 days of age) which is not solely explained by the concomitantly produced growth retardation.  相似文献   
102.
This study examined electromyogram (EMG) and skin conductance level (SCL) as mediators of neuropsychological test performance of alcoholics. Alcoholics and controls with high EMG performed less well than low EMG subjects on 12 measures of neuropsychological performance. For SCL, the alcoholics and controls in the Low Group did not differ from those in the High Group on any measure. Analyses that used information intake (Low EMG and High SCL) and rejection (High EMG and Low SCL) information postures (IPs) demonstrated that the intake group outperformed the rejection group on 10 neuropsychological measures. Subjects with intake IPs reported more stimulation, concentration, and interest during the tasks than did subjects with rejection IPs. Results suggest that IPs can be used to identify alcoholics with neuropsychological deficits.  相似文献   
103.
104.
Various forms of signal processing are used in modern ASP hearing aids. The present study investigated the relationship between sentence recognition ability and two types of signal processing used in commercially available hearing aids. Results indicated a significant improvement in sentence recognition ability employing an instrument with adaptive compression (variable release time) versus an instrument with an adaptive high-pass filter with short attack and release times. Data were obtained for a single-talker competing message at several message-to-competition ratios. The adaptive compression system may prove to be beneficial to hearing-impaired listeners in certain background noise environments.  相似文献   
105.
Fronto-ethmoidal mucocoeles: a histopathological analysis.   总被引:1,自引:0,他引:1  
From a series of 118 fronto-ethmoidal mucocoeles, 40 specimens have been submitted to detailed histological analysis. The frequency of each epithelial and sub-epithelial component is considered and reveals features which support a dynamic theory of bone resorption and formation rather than that of pressure erosion in the pathogenesis of mucocoeles.  相似文献   
106.
Facial reanimation after acoustic neuroma excision is currently accomplished using a variety of surgical techniques. A multi-institutional survey of patient perceptions of facial reanimation success was accomplished by mailing a questionnaire to 809 randomly selected members of the Acoustic Neuroma Association. Four hundred sixty patients who underwent 296 reanimation procedures responded. Facial to hypoglossal nerve anastomosis, tarsorrhaphy, and upper eyelid implants were most frequently performed. The patient's estimations of initial deficit, spontaneous recovery, and overall satisfaction with the reanimation procedures are discussed.  相似文献   
107.
Most authors consider the principal advantage of FG anastomoses (compared to microsurgical anastomoses) to be shorter operating time, reduced surgical trauma to oviduct stumps, and absence of tissue ischemia. These features promote reparative regeneration and decrease adhesion formation, resulting in complete recanalization of fallopian tubes. To date, the majority of work on FG is confined to the experimental development of surgical techniques. Investigations in reconstructive gynecological surgery are quite uncommon. The physical properties of FG and the positive results of available experimental studies suggest that further development of surgical techniques using FG in obstetrics and gynecology is worthwhile.  相似文献   
108.
109.
110.
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