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   1779565篇
  免费   126927篇
  国内免费   3987篇
耳鼻咽喉   23104篇
儿科学   58192篇
妇产科学   48416篇
基础医学   252488篇
口腔科学   51050篇
临床医学   156522篇
内科学   352435篇
皮肤病学   41008篇
神经病学   137755篇
特种医学   65631篇
外国民族医学   245篇
外科学   267729篇
综合类   39406篇
现状与发展   4篇
一般理论   557篇
预防医学   133876篇
眼科学   42191篇
药学   130213篇
  7篇
中国医学   4733篇
肿瘤学   104917篇
  2021年   14214篇
  2019年   15166篇
  2018年   22705篇
  2017年   16885篇
  2016年   18221篇
  2015年   20828篇
  2014年   28240篇
  2013年   41212篇
  2012年   58281篇
  2011年   61141篇
  2010年   35643篇
  2009年   32769篇
  2008年   56152篇
  2007年   59712篇
  2006年   60027篇
  2005年   57294篇
  2004年   55132篇
  2003年   52214篇
  2002年   50224篇
  2001年   94157篇
  2000年   96192篇
  1999年   79015篇
  1998年   20104篇
  1997年   17506篇
  1996年   17661篇
  1995年   16953篇
  1994年   15452篇
  1993年   14202篇
  1992年   58413篇
  1991年   56220篇
  1990年   53847篇
  1989年   51527篇
  1988年   46884篇
  1987年   45694篇
  1986年   42939篇
  1985年   40652篇
  1984年   29860篇
  1983年   25329篇
  1982年   14098篇
  1979年   26047篇
  1978年   17882篇
  1977年   15149篇
  1976年   14129篇
  1975年   14873篇
  1974年   18122篇
  1973年   17370篇
  1972年   16032篇
  1971年   14804篇
  1970年   13833篇
  1969年   12893篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
151.
152.
153.
Three hundred and twenty samples of subgingival plaque were obtained from 80 caucasian girls, ranging from 10 to 13 years of age. The samples were analyzed to verify the influence of age upon colonization of the gingival sulcus by microorganisms potentially pathogenic to the periodontal tissues. The gingival and plaque status were evaluated through the gingival index (GI) and plaque index (PlI) and the microflora was assessed by the enzymatic method benzoyl-arginine-naphthylamide (BANA). The results of the BANA test were positive for 62.50% of the tested individuals and 40% of the examined sites. The influence of age was statistically significant on BANA reactivity, and the number of positive sites was greater at 11 (57.5%) than at 12 years (28.8%).  相似文献   
154.
155.
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   
156.
157.
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   
158.
38 cases of acute multilocular osteomyelitis out of a total of 165 osteomyelitis patients were treated between 1974 and 1986 at the Department of Paediatric Surgery and Paediatric Diseases at the University of Mainz. Osteomyelitis in infants was separated from juvenile osteomyelitis because of the different problems inherent to this disease depending upon the age; likewise, multilocular remote involvement was separated from regional multiple involvement. It was found that distant involvement is of special importance in infancy. 6 of the 8 cases in this group presented with symmetrical involvement. This interesting phenomenon is described in this article for the first time in acute multilocular osteomyelitis; so far, it was known to occur only in chronic recurrent multifocal osteomyelitis (CRMO). The infants in this group were predominantly newborn who were particularly severely handicapped by predisposing factors such as necessary intensive-care measures or surgical interventions. Our findings showed that in this age group most of the problems occurred, namely: 3 deaths and 2 healing defects in 8 children. For this reason it is imperative to effect particularly close monitoring of multilocular acute osteomyelitis in infancy. This must be considered as a paediatric and paediatric-surgical emergency requiring not only accurate diagnostic measures but also early internistic and surgical treatment to improve the prognosis of this specific disease pattern.  相似文献   
159.
The Authors examine the correlation between hypertensive disorders of pregnancy and fetal growth. The results of a study of 342 pregnancies, confirm a significant correlation between hypertension and fetal growth retardation. These findings, so evident in moderate and severe hypertension, have also been confirmed in cases of mild hypertension. The medical treatment also in the pregnancies with mild hypertension, and a larger utilisation of operative deliveries, determined a decrease in perinatal mortality and morbidity.  相似文献   
160.
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