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   6148篇
  免费   473篇
  国内免费   8篇
耳鼻咽喉   27篇
儿科学   183篇
妇产科学   113篇
基础医学   856篇
口腔科学   52篇
临床医学   828篇
内科学   1015篇
皮肤病学   72篇
神经病学   644篇
特种医学   212篇
外科学   575篇
综合类   61篇
一般理论   12篇
预防医学   860篇
眼科学   199篇
药学   605篇
中国医学   7篇
肿瘤学   308篇
  2024年   8篇
  2023年   74篇
  2022年   90篇
  2021年   176篇
  2020年   126篇
  2019年   202篇
  2018年   167篇
  2017年   137篇
  2016年   165篇
  2015年   177篇
  2014年   199篇
  2013年   327篇
  2012年   478篇
  2011年   479篇
  2010年   270篇
  2009年   239篇
  2008年   386篇
  2007年   407篇
  2006年   413篇
  2005年   388篇
  2004年   341篇
  2003年   325篇
  2002年   301篇
  2001年   85篇
  2000年   87篇
  1999年   81篇
  1998年   47篇
  1997年   39篇
  1996年   29篇
  1995年   35篇
  1994年   23篇
  1993年   33篇
  1992年   21篇
  1991年   25篇
  1990年   17篇
  1989年   18篇
  1988年   12篇
  1987年   12篇
  1986年   15篇
  1985年   18篇
  1984年   14篇
  1983年   15篇
  1982年   7篇
  1981年   15篇
  1980年   13篇
  1979年   14篇
  1978年   8篇
  1976年   10篇
  1974年   8篇
  1965年   5篇
排序方式: 共有6629条查询结果,搜索用时 783 毫秒
61.
A new perfluorocopolymer coating for micropore hollow fiber gas exchangers was developed to improve gas exchange, reduce plasma leakage, and reduce blood-surface interactions. The present authors evaluated gas exchanger performance using this new coating in a prospective, randomized, controlled, unblinded, large animal model of CO2 retention. Adult sheep (30-40 kg), under general anesthesia, underwent cannulation of the carotid artery (12 F) and jugular vein (14 F). The perfluorocopolymer coated (n = 5) and uncoated (n = 5) gas exchangers were attached to an arteriovenous CO2 removal (AVCO2R) circuit. Blood gases, CO2 removal, and hemodynamics were monitored throughout the 6 hour study. Average CO2 removal was 107.6 +/- 15.6 ml/min (coated) vs. 93.0 +/- 13.9 ml/min (uncoated; p < 0.01). PaCO2 and CO2 removal for both coated and uncoated did not deteriorate significantly over the study. Average AVCO2R blood flow was 1,130 +/- 25 ml/min (coated) versus 1,101 +/- 79 ml/min (uncoated; p = not significant). Likewise, cardiac output and AVCO2R blood flow did not change over the duration of the study. No significant differences in the pressure gradient or resistance between devices (coated, 6.89 +/- 1.14 mm Hg/L/min; uncoated, 6.42 +/- 0.23 mm Hg/L/min) was noted. The authors concluded that the new perfluorocopolymer coated gas exchanger improved CO2 removal without compromising hemodynamics in an acute performance evaluation.  相似文献   
62.
In this study we have investigated a group of 29 Brazilian patients, who had been diagnosed with the lysosomal storage disorder, Mucopolysaccharidosis type I (MPS-I). MPS I is caused by a deficiency in the lysosomal hydrolase, alpha-L-iduronidase. Ninety percent of the MPS I patients in this study were genotyped and revealed 10 recurrent and thirteen novel IDUA gene mutations. Eight of these new mutations and three common mutations W402X, P533R, and R383H were individually expressed in CHO-K1 cells and analyzed for alpha-L-iduronidase protein and enzyme activity. A correlation was observed between the MPS I patient clinical phenotype and the associated mutant alpha-L-iduronidase protein/enzyme activity expressed in CHO-K1 cells. This was the first time that Brazilian MPS I patients had been thoroughly analyzed and highlighted the difficulties of mutation screening and clinical phenotype assessment in populations with high numbers of unique mutations.  相似文献   
63.
64.
65.
Becoming an informal caregiver for an adult living with dementia has been shown to have a significant impact upon the conception of identity. This study aimed to identify how identity is constructed online amongst caregivers of individuals living with dementia and how healthcare interactions can influence identity development through the analysis of online web blogs. Sixteen online blogs (172 entries) were selected through purposive and snowball sampling, and discourse analysis was used to analyse online identity construction for informal caregivers of adults living with dementia. Six areas of online identity construction were identified: changing family role; powerful expert social campaigner; being an advocate; guardian of their relative's selfhood; sustaining creative and spiritual individuality and wider community member in online and real life. Further to this, the importance of health and social care service interactions in the development of caregiver identity revealed that professionals must ensure person-centred service contacts for caregivers. This is a challenging task in the pandemic climate where interactions between health and social care professionals and caregivers are limited due to isolation measures. It is evident that the blog format can provide a forum through which the identity of the caregiver of an adult living with dementia can evolve. The six areas of identity construction reveal the multifaceted nature of identity for the caregiver and the value of belonging to an online community both in relation to identity construction and support. This finding is especially applicable in the current pandemic when accessing a face-to-face community is challenging for caregivers who may be shielding or living in isolation. The findings of this research can aid health and social care professionals in understanding the development of caregiver identity and in providing appropriate support during service interactions, on accessing virtual and face to face community support.  相似文献   
66.
Scope: B vitamers are co-enzymes involved in key physiological processes including energy production, one-carbon, and macronutrient metabolism. Studies profiling B vitamers simultaneously in parent–child dyads are scarce. Profiling B vitamers in parent–child dyads enables an insightful determination of gene–environment contributions to their circulating concentrations. We aimed to characterise: (a) parent–child dyad concordance, (b) generation (children versus adults), (c) age (within the adult subgroup (age range 28–71 years)) and (d) sex differences in plasma B vitamer concentrations in the CheckPoint study of Australian children. Methods and Results: 1166 children (11 ± 0.5 years, 51% female) and 1324 parents (44 ± 5.1 years, 87% female) took part in a biomedical assessment of a population-derived longitudinal cohort study: The Growing Up in Australia’s Child Health CheckPoint. B vitamer levels were quantified by UHPLC/MS-MS. B vitamer levels were weakly concordant between parent–child pairs (10–31% of variability explained). All B vitamer concentrations exhibited generation-specificity, except for flavin mononucleotide (FMN). The levels of thiamine, pantothenic acid, and 4-pyridoxic acid were higher in male children, and those of pantothenic acid were higher in male adults compared to their female counterparts. Conclusion: Family, age, and sex contribute to variations in the concentrations of plasma B vitamers in Australian children and adults.  相似文献   
67.
Background: Low energy availability results in physiological adaptations which contribute to unfavourable health outcomes. Little information exists on perceptions of nutritional advice to eat more food to maintain health and enhance performance. The aim of this study was to explore athletes’ and coaches’ perceptions towards advice to athletes to eat larger than their current quantities of food and to explore how nutritionists could deliver this advice. Methods: Semi-structured interviews (~20 min in length) were conducted using online communication technology, audio-recorded, and transcribed verbatim. The interview explored perceptions of the nutritional advice provided, its role in health and performance, and the challenges to eating larger amounts of food. Data were analysed using NVIVO 1.2 using an inductive thematic approach. Results: Nine elite athletes (female = 6; males = 3) and nine high-performance coaches (female = 3; male = 6) completed the semi-structured interviews. Athletes reported improved training consistency, fewer injuries and illnesses, and improved resilience when consuming adequate energy and nutrients to meet their needs. Lack of time and meal preparation difficulties were the main challenges faced to fuelling. Conclusions: Although education about under-fuelling is important, motivating, enabling, and supporting athletes to change behaviour is pivotal to increasing athlete self-awareness and to make long-term nutritional changes.  相似文献   
68.
教授对作假行为失查而受处罚   总被引:1,自引:0,他引:1  
上周 ,英国伦敦帝国大学口腔医学院临床生化系教授TimothyPeters被判定犯有严重的失职罪。他之所以遭到英国国家医学委员会的严厉谴责是因为他指导的一名低年资医师AnjanBanerjee发表了一篇捏造的研究报告 ,而他却失于督查和阻止。AnjanBanerjee医生现年 4 1岁 ,曾于1988年至 1991年期间在帝国大学医院作低年资医师 ,当时Peters教授是他的科研项目负责人。去年 ,他在《英国医学杂志》(BMJ 2 0 0 0 ;32 1:14 2 9)上发表了一篇伪造的研究报告 ,经英国国家医学委员会核实 ,认为存在欺骗行为 ,…  相似文献   
69.
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