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   15394篇
  免费   905篇
  国内免费   217篇
耳鼻咽喉   43篇
儿科学   1493篇
妇产科学   1920篇
基础医学   1401篇
口腔科学   33篇
临床医学   2499篇
内科学   1836篇
皮肤病学   57篇
神经病学   723篇
特种医学   305篇
外科学   1255篇
综合类   1912篇
一般理论   5篇
预防医学   1249篇
眼科学   18篇
药学   908篇
  9篇
中国医学   151篇
肿瘤学   699篇
  2024年   42篇
  2023年   256篇
  2022年   458篇
  2021年   644篇
  2020年   560篇
  2019年   529篇
  2018年   507篇
  2017年   484篇
  2016年   501篇
  2015年   474篇
  2014年   906篇
  2013年   1216篇
  2012年   790篇
  2011年   833篇
  2010年   743篇
  2009年   758篇
  2008年   740篇
  2007年   681篇
  2006年   717篇
  2005年   623篇
  2004年   521篇
  2003年   437篇
  2002年   304篇
  2001年   288篇
  2000年   277篇
  1999年   217篇
  1998年   167篇
  1997年   215篇
  1996年   138篇
  1995年   166篇
  1994年   172篇
  1993年   128篇
  1992年   103篇
  1991年   113篇
  1990年   85篇
  1989年   88篇
  1988年   67篇
  1987年   71篇
  1986年   50篇
  1985年   75篇
  1984年   70篇
  1983年   43篇
  1982年   53篇
  1981年   48篇
  1980年   33篇
  1979年   30篇
  1978年   32篇
  1977年   16篇
  1976年   10篇
  1975年   9篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
61.
Intrauterine growth restriction is known to be associated with many medical problems for the baby, both before and after delivery. The mechanisms involved in fetal growth are not well understood, with an increasing range of metabolic diseases being implicated. Several key genes involved in normal embryonic and fetal growth and development are now known to be imprinted. Disruption of this parent-specific mono-allelic expression causes phenotypic changes, many of which are important for growth and development. Two growth disorders, Beckwith–Wiedemann syndrome and Silver–Russell syndrome, are discussed in detail as they represent well-characterized phenotypes that arise as a consequence of disrupted imprinting. These human models will allow us to elucidate key genes and mechanisms important in normal fetal growth.  相似文献   
62.
第一产程异常胎心监护图形与新生儿结局的关系   总被引:11,自引:0,他引:11  
目的 探讨第一产程异常胎心监护图形与新生儿结局的关系。方法 回顾分析 2 0 0 2年 8月至 2 0 0 3年 6月在我院足月单胎头位分娩产妇 ,第一产程中胎心率 (FHR)异常图形 2 1 7例 (观察组 )和FHR正常图形的2 6 9例 (对照组 )的临床资料。结果 第一产程异常FHR图形的发生率为 4 4 7% ,常见类型为轻度变异减速(6 4 5 % )、基线变异减弱 (2 1 6 % )和轻度心动过速 (1 2 0 % )。晚期减速、基线变异减弱和重度变异减速是导致新生儿窒息的危险因素。观察组羊水过少 (5 1 % )、脐带缠绕 (2 2 6 % )、羊水粪染 (1 0 6 % )、新生儿窒息 (6 5 % )、新生儿转入NICU(1 0 1 % )的发生率和剖宫产率 (31 8% )明显高于对照组 (P <0 0 5 )。结论 第一产程异常FHR图形的发生率较高 ,其中晚期减速、基线变异减弱、重度变异减速与新生儿窒息的发生相关 ,其他图形可在严密监护下继续试产  相似文献   
63.
新生儿脐血红细胞葡萄糖6磷酸脱氢酶缺乏筛查结果分析   总被引:4,自引:0,他引:4  
目的 了解广东省东莞市莞城地区新生儿脐血红细胞葡萄糖6磷酸脱氢酶(G-6-PD)缺乏的发生率。方法 9676例活产新生儿生后即取脐血,采用定量法测定红细胞G6PD/6PGD的比值。低于1.0者为G-6-PD缺乏。结果 测得G-6-PD缺乏的患儿265例,总发生率为2.74%。其中男230例,发生率为4.07%;女35例,发生率为0.87%。男性发生率明显高于女性(χ^2=90.75,P<0.001)。结论 脐血G-6-PD活性筛查,能比较准确地检测出G-6-PD缺乏患儿,指导临床对其并发症进行早期干预,避免智力低下等后遗症的发生,提高人口素质。  相似文献   
64.
The aim of this paper was to review the clinical applications of four-dimensional ultrasonography in the assessment of fetal behavior. With the use of a computerized database, articles on three-dimensional ultrasonography were reviewed. Several applications of dynamic three-dimensional ultrasonography have been reported, including imaging of fetal movements, facial expression and fetal hand movements. The importance of the assessment of fetal behavior by four-dimensional sonography is stressed. Four-dimensional sonography seems to be a useful imaging tool for clinical problem solving in perinatology, especially in observing the development of the central nervous system in utero.  相似文献   
65.
66.
67.
68.
Objective To assess the effect of lung protective ventilation on outcome of children with acute respiratory distress syndrome(ARDS).Methods Between January 1999 and December 2007,43 children with ARDS were enrolled from PICU of Shanghai Children's Medical Center and assigned to the protective-ventilation group(group A) or the conventional-ventilation group(group B).The patients in group A (from January 2004 to December 2007)received lower tidal volume(6~7 ml/kg) and high levels of positive end-expiratory pressure(PEEP),and optimal oxygenation was achieved by adjusting FiO2 and PEEP.The patients in group B(from January 1999 to December 2003) received relatively higher tidal volume(8~12 mL/kg) with lower PEEP(2~6 cm H2O),and optimal oxygenation was achieved by adjusting FiO2.Tidal volume,PEEP,arterial blood gas,mortality and the number of ventilator-free days were compared between the two groups.Results Since protective ventilation was adopted after 2004,tidal volume was significantly lower in group A[(7.09±1.66)ml/kg]as compared with that in group B[(9.82±2.31) ml/kg](P=0.001).PEEP was significantly higher in group A[(7.15±2.08) cm H2O]as compared with that of group B[(5.40 + 1.84) cm H2O](P=0.021).The mortality was 30.3% in group A and 60.0% in group B.The number of ventilator-free days were(10.88±8.84) d in group A and(8.40±10.86) d in group B.Although mortality was lower and number of ventilator-free days was greater in group A,no significant differences were found between the two groups(P>0.05).Conclusion Lung protective ventilation may improve the outcome for pediatric patients with ARDS,however,larger trials are required before a definite conclusion can be reached.  相似文献   
69.
Aim: The aim of this study is to determine the separate effects of social class, income, education and area of residence on psychological distress. The study also assesses whether the association between prevalence of high score on the 12-item General Health Questionnaire (GHQ 12) and social class is independent of other variables. Method: Psychological distress was assessed by means of the GHQ 12. The study covered 1092 adults aged 15 years or more living in two different quarters of Antalya. Social class status was defined by occupational position, with income, education and area of residence treated as confounders. Chi-square and logistic regression analyses were used to evaluate the data. Results: Large inequalities in psychological distress by all variables were observed. Psychological distress was significantly associated with class status, after adjusting for income, education, area of residence and other potential confounders (age, sex and marital status). Class inequalities in psychological distress were observed between blue-collar workers/unqualified employees and bourgeoisie. Conclusions: These findings support the view that the recent widening of inequalities among social classes in Turkey pose a substantial threat to health. Accepted: 5 November 1999  相似文献   
70.
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