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   404257篇
  免费   25643篇
  国内免费   10214篇
耳鼻咽喉   4116篇
儿科学   10346篇
妇产科学   6786篇
基础医学   30962篇
口腔科学   8059篇
临床医学   47176篇
内科学   57001篇
皮肤病学   4650篇
神经病学   29288篇
特种医学   10651篇
外国民族医学   32篇
外科学   38735篇
综合类   64685篇
现状与发展   13篇
一般理论   29篇
预防医学   37076篇
眼科学   5377篇
药学   36751篇
  464篇
中国医学   34254篇
肿瘤学   13663篇
  2023年   6096篇
  2022年   11026篇
  2021年   15152篇
  2020年   14214篇
  2019年   19661篇
  2018年   17274篇
  2017年   14418篇
  2016年   12152篇
  2015年   11569篇
  2014年   23844篇
  2013年   25220篇
  2012年   22042篇
  2011年   23777篇
  2010年   19289篇
  2009年   17717篇
  2008年   17436篇
  2007年   18004篇
  2006年   16104篇
  2005年   13976篇
  2004年   11396篇
  2003年   10086篇
  2002年   8106篇
  2001年   7362篇
  2000年   6162篇
  1999年   5309篇
  1998年   4312篇
  1997年   4109篇
  1996年   3458篇
  1995年   3238篇
  1994年   3123篇
  1993年   2492篇
  1992年   2450篇
  1991年   2151篇
  1990年   1884篇
  1989年   1686篇
  1988年   1578篇
  1987年   1381篇
  1986年   1294篇
  1985年   4071篇
  1984年   5034篇
  1983年   3513篇
  1982年   3968篇
  1981年   3717篇
  1980年   3272篇
  1979年   2988篇
  1978年   2589篇
  1977年   1940篇
  1976年   2182篇
  1975年   1645篇
  1974年   1438篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
特殊部位异位妊娠的临床分析   总被引:1,自引:0,他引:1  
目的探讨特殊部位异位妊娠的临床特点,误诊原因及治疗原则。方法对1996年1月至2003年12月诊治的256例特殊部位异位妊娠进行回顾性分析。结果特殊部位异位妊娠发生率占同期异位妊娠的3.36%,术前诊断率48.4%,所有的患者均行手术。视术中情况进行不同的处理,所得标本均经病理切片证实,全部患者愈后良好。结论特殊部位异位妊娠的临床表现不典型,容易漏诊误诊,一旦怀疑本病应尽早住院,及时明确诊断并手术,患者愈后良好。  相似文献   
22.
23.
24.
25.
Objectives –  To assess long‐term functioning and disability after traumatic brain injury (TBI). Material and methods –  Individuals (n = 88) in Norrbotten, northern Sweden, who had been transferred for neurosurgical care were assessed with internationally established TBI outcome measures 6–15 years post‐injury. Results –  There was an improvement in overall outcome from discharge from inpatient rehabilitation to follow‐up. Many individuals had a high degree of motor and cognitive functioning, which enabled them to live independently in their own home without assistance, but there remained a disability related to community reintegration and social participation. This affected their productivity and to some degree their marital stability. The remaining disability and reduced productivity were related to the age at injury and the injury severity. Conclusions –  Our data showed that individuals with a TBI can achieve and maintain a high degree of functioning many years after the injury. Increasing age and a greater injury severity contributed to their long‐term disability.  相似文献   
26.
27.
28.
While much time has been spent deliberating about the definition of play, little emphasis has been placed on what children themselves perceive as play. The aim of the present study was to examine social context as a cue for children's perceptions of play and learning. Ninety-two children aged between four and six years (mean four years nine months) participated in the study and completed the Activity Apperception Story Procedure. Children were asked to sort photographic stimuli into those they believed depicted play/not play and learning/not learning. Each of the stimuli were identified by independent raters as containing one of the following social cues; teacher absence (solitary activity, parallel activity or cooperative activity) or teacher presence (teacher involved activity or teacher directed activity). Findings revealed that children associated teacher absence with play. More specifically, children made links between play and the presence of peers (parallel and cooperative activity). Findings are discussed in relation to play in the early years curriculum, differences in children's early educational experiences and the importance of understanding children's perceptions of play.  相似文献   
29.
Summary Aspergillosis belongs to the group of mycotic diseases of paranasal sinuses. The invasive forms, and particularly the fulminant forms, are potentially fatal. Isolated aspergillosis of the sphenoid sinus or the clivus is a difficult diagnosis, since the often misleading clinical manifestations of this rare disease develop late. These patients become apparent by neurological signs such as cavernous sinus syndrome, pseudotumor of the pituitary or the orbit. Diagnosis is often made intra-operatively or on histological examination. We report a case of invasive aspergillosis uniquely involving the sellar area revealed by clinical features suggesting a pseudotumor of the pituitary. Although such lesions are almost always seen in immune suppressed subjects, in our case, the patient was immune competent and had no past history of sinusitis. The question of whether, and when to perform limited or extensive surgery remains an issue for discussion, owing to the rarity of this disease honed by lack of experience. It depends on several factors: the kind of disease, the immunity, the subtype of invasive fungal sinusitis and the degree of tissue invasion.  相似文献   
30.
X Dong  M He  X Song  B Lu  Y Yang  S Zhang  N Zhao  L Zhou  Y Li  X Zhu  R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.  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