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   643803篇
  免费   32444篇
  国内免费   763篇
耳鼻咽喉   8452篇
儿科学   20450篇
妇产科学   14888篇
基础医学   107888篇
口腔科学   16418篇
临床医学   55588篇
内科学   123433篇
皮肤病学   15483篇
神经病学   43039篇
特种医学   22232篇
外国民族医学   54篇
外科学   92060篇
综合类   8204篇
现状与发展   2篇
一般理论   142篇
预防医学   49806篇
眼科学   14560篇
药学   49130篇
  1篇
中国医学   1659篇
肿瘤学   33521篇
  2021年   6272篇
  2019年   6556篇
  2018年   10243篇
  2017年   6740篇
  2016年   7296篇
  2015年   8076篇
  2014年   10233篇
  2013年   15205篇
  2012年   23887篇
  2011年   26290篇
  2010年   14404篇
  2009年   11907篇
  2008年   22794篇
  2007年   24980篇
  2006年   23894篇
  2005年   23196篇
  2004年   21953篇
  2003年   20993篇
  2002年   20187篇
  2001年   25675篇
  2000年   26725篇
  1999年   21710篇
  1998年   5685篇
  1997年   4634篇
  1996年   4678篇
  1995年   4338篇
  1992年   15485篇
  1991年   16728篇
  1990年   16729篇
  1989年   16267篇
  1988年   14847篇
  1987年   14694篇
  1986年   13696篇
  1985年   13100篇
  1984年   9734篇
  1983年   8247篇
  1982年   4291篇
  1979年   9201篇
  1978年   6542篇
  1977年   5309篇
  1976年   5670篇
  1975年   6822篇
  1974年   7668篇
  1973年   7432篇
  1972年   6818篇
  1971年   6551篇
  1970年   6104篇
  1969年   5710篇
  1968年   5380篇
  1967年   4807篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
81.
Diffusely adhering Escherichia coli (E. coli) strains (DAEC) represent a potential cause of diarrhoea in infants, and the detection of type three secretion system (TTSS) genes in DAEC would substantiate their pathogenic nature. In this work, four isolates of DAEC, recovered from stools of diarrhoeic children, were analysed by PCR, in order to detect the presence of TTSS genes. Primers targeted to the escC, escJ, escN and escV, some of the most conserved TTSS genes in enteropathogenic and enterohaemorrhagic Escherichia coli (EPEC and EHEC), were used in order to verify the occurrence of homologous genes in our DAEC isolates. By this approach, we were able to characterise DNA fragments corresponding to putative escJ and escN genes in all DAEC isolates. Furthermore, DNA fragments homologous to the escC and escV genes were also amplified from all isolates. Besides the similarity found among the DAEC esc homologues with EPEC and EHEC esc genes, the nucleotide sequence analysis of the flanking regions of the amplified DNA fragments suggests that the putative DAEC esc genes are organised in the same manner as observed in EPEC and in EHEC strains. The results described here provide strong evidence for the presence of a TTSS in the DAEC strains analysed, implicating a pathogenic nature of these isolates.  相似文献   
82.
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   
83.
84.
85.
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   
86.
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   
87.
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   
88.
89.
90.
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