首页 | 官方网站   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   3160357篇
  免费   228022篇
  国内免费   4913篇
医药卫生   3393292篇
  2018年   34097篇
  2017年   25621篇
  2016年   28797篇
  2015年   32660篇
  2014年   45835篇
  2013年   69250篇
  2012年   95422篇
  2011年   101702篇
  2010年   60453篇
  2009年   56996篇
  2008年   96245篇
  2007年   102828篇
  2006年   104003篇
  2005年   101183篇
  2004年   97066篇
  2003年   93618篇
  2002年   91099篇
  2001年   140650篇
  2000年   144270篇
  1999年   121677篇
  1998年   35860篇
  1997年   31560篇
  1996年   31928篇
  1995年   30053篇
  1994年   27878篇
  1993年   26210篇
  1992年   95924篇
  1991年   93831篇
  1990年   91972篇
  1989年   88992篇
  1988年   82230篇
  1987年   80727篇
  1986年   76355篇
  1985年   73188篇
  1984年   54663篇
  1983年   46806篇
  1982年   28143篇
  1981年   25187篇
  1979年   51149篇
  1978年   36363篇
  1977年   30737篇
  1976年   29280篇
  1975年   31897篇
  1974年   37899篇
  1973年   36332篇
  1972年   34317篇
  1971年   32356篇
  1970年   29952篇
  1969年   28644篇
  1968年   26634篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
91.
目的:描述胚胎种植前遗传诊断在1例携带Ⅰ型白细胞黏附缺陷病(LAD-1)携带者并完成健康妊娠夫妇中的应用。设计:病例报道。机构:大学医院生殖中心。患者:1例男女双方都是LAD-1携带者的夫妇,女方CD18基因的外显子4携带有G400A置换,男方的外显子5携带有C562T置换。干预:标准体外受精(IVF)后第3天行卵裂期活检和分裂球遗传分析以检测2处突变以及21号染色体标记物。主要观察指标:1个未罹患LAD-1婴儿的出生。结果:得到15个卵母细胞,其中10个受精。8个胚胎适宜胚胎活组织检查。  相似文献   
92.
背景:浴光疗同步治疗银屑病的有效性与UVB和死海盐的多靶点作用有关,同步治疗能够起到协同功效。目的:本回顾性研究的目的:①评价浴光疗同步治疗各种临床类型银屑病的有效性;②观察治疗反应有无不同;③获得更多数据以预测对不同类型银屑病的治疗效果,以便针对患者的类型选择治疗效果良好的方法。方法:根据Regensburg计划,患者接受了一个包括35次治疗的基础同步浴光疗疗程,随后又接受了一个包括25次治疗的维持治疗疗程。治疗中每周进行PASI评分以评价患者的皮肤状态。对373例按计划完成基础疗程的患者和其中78例完成维持疗程的患者的治疗…  相似文献   
93.
AIM: To evaluate whether the introduction of a strict protocol approach based on the systemic evaluation of critically ill pregnant women with complications of abortion affected outcome. SETTING: Indigent South Africans managed in the regional and tertiary hospitals of the Pretoria Academic Complex. METHOD: Since 1997 a standard definition of severe acute maternal morbidity (SAMM) has been used in the Pretoria Academic Complex. All cases of SAMM and maternal deaths were entered on the Maternal Morbidity and Mortality Audit System programme. A comparison of outcome of severely ill women who had complications of abortion was made between 1997-1998 (original protocol) and 2002-2004 (strict protocol). OUTCOME MEASURES: The mortality index and prevalence of organ system failure or dysfunction. RESULTS: In 1997-1998 there were 43 women with SAMM who survived and a further 10 maternal deaths due to complications of abortion, compared with 107 women with SAMM and 7 maternal deaths during 2002-2004. The mortality index declined from 18.9% in 1997-1998 to 6.1% in 2002-2004 (p = 0.02, odds ratio 0.28, 95% confidence limits 0.10 - 0.79). Significantly more women had hypovolaemic shock in 2002-2004 compared with 1997-1998 (54.4% v. 35.8%, p = 0.04), but fewer women had immune system failure including septic shock (18.4% v. 47.2%, p = 0.0002) and metabolic dysfunction (0 v. 5.7%, p = 0.03) and there was a trend to less renal failure (10.5% v. 22.6%, p = 0.06) and cardiac failure (4.4% v. 13.2%, p = 0.08). CONCLUSION: The strict protocol approach based on systemic evaluation in managing critically ill pregnant women with complications of abortion, coupled with an intensive, regular feedback mechanism, has been associated with a reduction in the mortality index.  相似文献   
94.
Using the SF-12 to measure physical and mental functioning, the authors examine the intra-individual changes in health-related quality of life (HRQOL) 6 months post-discharge for depressed older adults. In addition, they examine three sets of predictors that might influence these changes. The sample of depressed older adults was recruited from an inpatient geropsychiatry unit. Although their physical and mental health scores on the SF-12 were lower than comparable norms, the sample showed an average increase in their mental functioning but a decrease in the physical functioning over the 6 months. Negative life-events were significant predictors of people who reported no change in their mental health functioning and decreases in their physical health functioning. Interestingly, those who experienced positive life events were more likely to report declines and younger participants were more likely to report no change in their physical functioning. The findings indicate that the effects of depression on HRQOL can have enduring effects on a sample of previously hospitalized older adults. The significance of life event changes might signify the importance of taking into account non-traditional areas of medical interventions. Further, the findings indicate the usefulness of the SF-12 quantifying HRQOL outcomes.  相似文献   
95.
96.
97.
98.
BACKGROUND: This study examines trends in the presentation and surgical management of acute diabetic foot problems in a single institution. METHOD: Prospective audit of all diabetic patients who had a primary procedure for critical lower limb ischaemia (CLI) and/or foot sepsis between 1st January 1990 and 31st December 2002. Primary and secondary intervention, mortality and limb salvage rate within 6 weeks of the index procedure were recorded. RESULTS: There were 661 patients (417 men and 244 women of median age 69, range 31-99, years) with 799 affected limbs. CLI alone was present in 625 (78%) limbs, combined CLI and foot sepsis in 53 (7%) and foot sepsis alone in 121 (15%). The primary intervention was minor amputation in 323 (40%) limbs, revascularisation in 288 (36%), major amputation in 185 (23%) and sympathectomy in three limbs. Within 6 weeks, 125 (16%) limbs required secondary intervention, the peri-procedural mortality rate was 38 of 924 (4%), and the limb salvage rates for patients with CLI, combined CLI and sepsis and sepsis alone were 66, 66 and 80%, respectively. There was a significant decline in the proportion of patients presenting with CLI alone and a significant increase in the proportion presenting with combined CLI and sepsis and sepsis alone. In patients with CLI alone, there was a significant increase in the primary major amputation rate and a significant decline in the minor amputation rate with no significant change in the revascularisation rate. CONCLUSION: There has been a progressive decline in the proportion of patients presenting with CLI alone and a greater proportion of patients presenting with an element of foot sepsis. In patients with CLI alone, the primary major amputation rate has increased at the expense of a decline in minor amputation rate.  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-23

京公网安备 11010802026262号