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   1308207篇
  免费   94538篇
  国内免费   2250篇
耳鼻咽喉   18631篇
儿科学   42860篇
妇产科学   38303篇
基础医学   190852篇
口腔科学   36863篇
临床医学   110780篇
内科学   259755篇
皮肤病学   26875篇
神经病学   102429篇
特种医学   51211篇
外国民族医学   366篇
外科学   202510篇
综合类   26615篇
现状与发展   1篇
一般理论   304篇
预防医学   94014篇
眼科学   29589篇
药学   99395篇
  1篇
中国医学   2564篇
肿瘤学   71077篇
  2018年   12938篇
  2016年   11043篇
  2015年   12665篇
  2014年   17379篇
  2013年   26024篇
  2012年   36136篇
  2011年   38514篇
  2010年   22646篇
  2009年   21306篇
  2008年   37068篇
  2007年   40077篇
  2006年   40446篇
  2005年   39559篇
  2004年   37967篇
  2003年   36825篇
  2002年   36203篇
  2001年   58322篇
  2000年   59789篇
  1999年   50902篇
  1998年   14471篇
  1997年   13004篇
  1996年   13222篇
  1995年   12477篇
  1994年   11873篇
  1993年   10964篇
  1992年   41086篇
  1991年   40442篇
  1990年   39961篇
  1989年   38751篇
  1988年   36177篇
  1987年   35408篇
  1986年   33765篇
  1985年   32194篇
  1984年   23970篇
  1983年   20857篇
  1982年   12427篇
  1981年   10955篇
  1979年   22666篇
  1978年   15900篇
  1977年   13748篇
  1976年   12979篇
  1975年   14218篇
  1974年   16697篇
  1973年   16108篇
  1972年   15339篇
  1971年   14240篇
  1970年   13226篇
  1969年   12745篇
  1968年   11990篇
  1967年   10489篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
92.
93.
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   
94.
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   
95.
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   
96.
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   
97.
98.
Background The appearance of eosinophils is a hallmark sign of the allergic late-phase response (LPR). Eosinophil cationic protein (ECP), a readily measurable product released from activated eosinophils, has so far not been evaluated in the ocular LPR. Objective Two sets of trials were performed in order to investigate changes of local and systemic eosinophil activity and their possible link with symptoms and hyper-reactivity in the allergic LPR in the eye. Methods In the first experiment, ECP was analysed in tears and serum and the clinical reaction was evaluated during a 72-h time–course after a single, high-dose allergen challenge out of season in one eye of 15 pollen-sensitized volunteers. In a second experiment, the hypothesis of an increased clinical response to an allergen challenge in an eye that had been provoked with allergen 48h previously was tested in nine sensitized individuals. Results In the first experiment, symptoms at 10 min and 2, 4, 6, 8 and 24 h significantly exceeded base line scores of the challenged eyes. Tear ECP was significantly elevated in challenged eyes compared to contralateral eyes at 6, 8 and 24 h. In addition, symptoms and ECP release correlated significantly at the 24-h evaluation. Serum ECP remained unchanged throughout the study period. In the second experiment, conjunctival hyperreactivity 48h after an allergen challenge was not confirmed. Conclusion ECP secretion occurs in the experimental ocular LPR and is in part associated with the magnitude of the clinical reaction, which suggests a truly pathogenic role of the activated eosinophil in pollen-induced allergic conjunctivitis.  相似文献   
99.
100.
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