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   1413544篇
  免费   97918篇
  国内免费   2297篇
耳鼻咽喉   19952篇
儿科学   46143篇
妇产科学   41079篇
基础医学   206736篇
口腔科学   40194篇
临床医学   116012篇
内科学   281582篇
皮肤病学   30373篇
神经病学   110397篇
特种医学   53438篇
外国民族医学   385篇
外科学   212801篇
综合类   27182篇
现状与发展   1篇
一般理论   321篇
预防医学   108624篇
眼科学   32864篇
药学   108426篇
  1篇
中国医学   3024篇
肿瘤学   74224篇
  2018年   16092篇
  2017年   11583篇
  2016年   12700篇
  2015年   14518篇
  2014年   19239篇
  2013年   29377篇
  2012年   42161篇
  2011年   45092篇
  2010年   25697篇
  2009年   23296篇
  2008年   42386篇
  2007年   45909篇
  2006年   46175篇
  2005年   45091篇
  2004年   43135篇
  2003年   41653篇
  2002年   40909篇
  2001年   61751篇
  2000年   63653篇
  1999年   53802篇
  1998年   14794篇
  1997年   13190篇
  1996年   13422篇
  1995年   12659篇
  1994年   12023篇
  1992年   42718篇
  1991年   41871篇
  1990年   41417篇
  1989年   40012篇
  1988年   37371篇
  1987年   36501篇
  1986年   34905篇
  1985年   33232篇
  1984年   24724篇
  1983年   21484篇
  1982年   12740篇
  1981年   11253篇
  1979年   23612篇
  1978年   16542篇
  1977年   14372篇
  1976年   13586篇
  1975年   14938篇
  1974年   17574篇
  1973年   17027篇
  1972年   16214篇
  1971年   15134篇
  1970年   14042篇
  1969年   13634篇
  1968年   12896篇
  1967年   11296篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
Variations of the medial and inferior choanal limits may facilitate snoring. These are: 1) short vomer without crista choanalis vomeris and adaptational formations, 2) extremely concave posterior margin of the hard palate leading to disproportion between the muscular and aponeurotic part of m. tensor veli palatini and hence to a flabby soft palate especially during sleep, and 3) neonatal relation of the height and width of the choane resulting in a very large choanal region instead of relative reduction of choanal width compared to its increasing height. All these variations result in a flabby soft palate especially during sleep and may lead to formation of whirles of inspired air and snoring.  相似文献   
94.
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   
95.
96.
97.
The degree of metabolic acidosis at birth has been calculated in cord artery and vein samples from 21 term fetuses with cord artery pH less than 7.20. The aim of the study was to compare base deficit values calculated from either Siggaard-Andersen alignment nomogram (BD blood) or the Acid-Base chart (BD extra cellular fluid, BDecf). BDblood was found to be consistently higher in the cord artery as compared with BDecf, 13.2 +/- 3.5 and 9.9 +/- 2.9 mmol/l (Mean +/- SD), respectively. A significant correlation was found between cord artery PCO2 and BDblood whereas BDecf appeared unaffected by PCO2. In cases with cord entanglement BDecf a-v differences were increased to 3.4 +/- 2.3 mmol/l as compared with the small a-v difference noted in acidotic cases without cord entanglement, 1.1 +/- 1.25 mmol/l. It is speculated that with acutely emerging, intermittent asphyxia due to cord compression, a cord artery and vein difference in metabolic acidosis may exist and where the vein captures the basal level and the artery the acute changes. It is concluded that BDecf in both cord artery and vein add valuable information on the mechanisms behind metabolic acidosis.  相似文献   
98.
We tested the urine of 30 infants 6 weeks to 7 months of age after they received standard 10-micrograms (0.5-ml) doses of HbOC (HibTITER) Haemophilus influenzae b (Hib) conjugate vaccine for the presence of Hib antigenuria using a commercially available latex particle agglutination assay (Directigen). Urines were collected within 1 hour, from 1 to 3 hours, at 24 hours and at 3, 6 and 9 days after vaccine administration and reactions were quantitated from 0 to 3+. In contrast to previous studies in older children which showed little or no antigenuria following HbOC vaccination, our study shows that in infants intense Hib antigenuria is evident within 2 to 3 hours and persists 3 days after vaccine administration and that less intense antigenuria may be detected in some infants for several days. With efficacious vaccines now being used in 2- to 6-month-old infants, invasive Hib disease may soon be limited to infants of this age just before their seroconversion. It should be recognized that antigenuria occurs for several days after vaccination with Hib conjugate vaccines and that it could be erroneously interpreted as evidence of invasive Hib infection.  相似文献   
99.
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   
100.
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   
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