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   41883篇
  免费   3503篇
  国内免费   710篇
耳鼻咽喉   208篇
儿科学   1968篇
妇产科学   954篇
基础医学   2732篇
口腔科学   478篇
临床医学   6888篇
内科学   4367篇
皮肤病学   182篇
神经病学   2295篇
特种医学   689篇
外科学   3971篇
综合类   5373篇
现状与发展   1篇
一般理论   3篇
预防医学   10718篇
眼科学   209篇
药学   2533篇
  32篇
中国医学   600篇
肿瘤学   1895篇
  2024年   106篇
  2023年   906篇
  2022年   1939篇
  2021年   2432篇
  2020年   2096篇
  2019年   1876篇
  2018年   1827篇
  2017年   1807篇
  2016年   1869篇
  2015年   1815篇
  2014年   3133篇
  2013年   3545篇
  2012年   2622篇
  2011年   2709篇
  2010年   2173篇
  2009年   1963篇
  2008年   1931篇
  2007年   1839篇
  2006年   1521篇
  2005年   1220篇
  2004年   1000篇
  2003年   811篇
  2002年   687篇
  2001年   589篇
  2000年   535篇
  1999年   431篇
  1998年   329篇
  1997年   298篇
  1996年   256篇
  1995年   210篇
  1994年   188篇
  1993年   185篇
  1992年   140篇
  1991年   133篇
  1990年   91篇
  1989年   112篇
  1988年   97篇
  1987年   86篇
  1986年   53篇
  1985年   99篇
  1984年   60篇
  1983年   49篇
  1982年   67篇
  1981年   35篇
  1980年   46篇
  1979年   47篇
  1978年   35篇
  1977年   19篇
  1976年   17篇
  1975年   17篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
71.
基于混合遗传算法的心脏病决策支持系统研究   总被引:1,自引:0,他引:1  
将遗传算法和 BP算法相结合 ,建立了一个基于混合遗传算法的心脏病决策支持系统来鉴别诊断五种常见心脏病 (冠心病 ,高血压性心脏病 ,风湿性心脏病 ,慢性肺原性心脏病和先天性心脏病 )。一个含有 35 2份心脏病的数据库用来构建和测试了该系统。实验结果表明 ,构建的系统对这五种心脏病均有较好的诊断识别率 ,系统的平均识别准确性达 90 .6 % ,各疾病的用户准确性和程序准确性均大于 85 .0 % ,表现出良好的心脏病的临床诊断决策支持能力  相似文献   
72.
目的:探讨肝外胆管癌的诊断和治疗的体会。方法:回顾性总结手术治疗的32例肝外胆管癌的临床资料、手术方式、手术并发症及生存率,并复习相关文献资料。结果:本组病例获根冶性切除14例,姑息切除2例,胆道引流术16例;手术并发症10例(31.3%),手术死亡1例(3.1%)。其中22例获定期随访,存活一年以上的有12例(12/22),至今存活8例。结论:早期诊断、正确的评估、合理的术式选择能提高疗效。降低手术并发症及死亡率。  相似文献   
73.
Hepatocyte isolation from pig livers after warm ischaemic injury   总被引:9,自引:0,他引:9  
Abstract Hepatocyte cultures have been used extensively for a wide variety of physiological, pharmacological and experimental studies. The warm ischaemic period before isolation is kept to a minimum to achieve a high yield of cells isolated and a good viability for culture. We have recently introduced a new concept of liver resuscitation after warm ischaemia that is based on a 3-h reperfusion period with an improved perfusate and simultaneous dialysis. In this study, we applied the new technique for hepatocyte isolation from livers subjected to 80 min of complete ischaemia at 37 °C. Cell yield was improved by a resuscitating perfusion from 58% to 73% and viability from 39% to 76%.  相似文献   
74.
本文根据34例电击伤临床资料,分析早期处理与病人全身情况、局部损伤愈合以及并发症的关系.并讨论间生态组织的处理原则.结果表明:伤后1天内与伤后3天以上就诊的病人比较,前者全身情况良好,创面感染率低,局部损伤用皮瓣或(和)皮片覆盖效果满意,并发症及截肢率均较低  相似文献   
75.
本实验对腹腔感染造成多器官衰竭的动物观察了不同全静脉营养配方在代谢支持中的作用。结果显示:在兔感染性多器官衰竭早期,实行代谢支持能够不同程度地增加体重、促进蛋白质合成和扭转负氮平衡。适当减低糖供给的非蛋白热量可以减轻应激反应,增加氮保留和改善肺功能。供给氨基酸过多则增加应激反应、增加尿氮排出和加重呼吸负担。  相似文献   
76.
Single photon emission computerized tomography (SPECT) is now widely used as one of the tools in evaluating cerebral blood flow (CBF). The authors report the CBF changes in childhood hydrocephalus. Five pediatric cases studied by 123I-IM SPECT in children are presented. The authors counted radioactivities both in early and delayed images in each patient, and calculated the reabsorption ratio (RR). Two negative-RR cases and three positive-RR cases were found. All of the negative-RR patients had a poor prognosis, while all of the positive-RR patients had a favorable outcome.  相似文献   
77.
Polyunsaturated fatty acids (PUFAs) are components of cell membranes and may play an immunomodulating role in the pathogenesis of atopic dermatitis (AD). The goal was to determine the impact of PUFAs on AD by dietary supplementation of infants. Based on the parents' decision on their babies' primary feeding, mothers and newborns were randomized to the supplementation with gamma-linolenic acid (GLA) or placebo for up to 6 months. Breastfed infants received GLA by supplementing their mothers. Formula diet was commercial whey hydrolysate unsupplemented with PUFAs. Of 131 eligible infants, 24 developed AD within the first year of life. Of these, nine belonged to the exclusively breastfed group (n = 58), 14 to the combined-fed group (n = 53), and one to the never breastfed group (n = 20). We could not find an influence of GLA on the development of AD. In subjects with AD, at 1 yr of age the serum-immunoglobulin E (IgE) was the lowest in the GLA-supplemented group A-subjects. In the GLA-supplemented group, GLA-levels in breast milk were similar in atopic and non-atopic infants. In the non-supplemented group the GLA-content of breast milk was 0.07% of total fatty acids in atopic infants vs. 0.17% in non-atopic infants (p < 0.01). Dietary GLA-supplementation could not prevent AD. Interestingly, the number of infants developing AD was the lowest in never breastfed children. In infants suffering from AD, GLA-supplementation seemed to reduce total IgE in the first year of life.  相似文献   
78.
OBJECTIVE: The GRIF automated feedback system produces real-time comments on the appropriateness of diagnostic tests ordered by general practitioners (GPs) based on recommendations from accepted national and regional practice guidelines. We investigated the experiences of GPs with this system and, more specifically, with the recommendations produced by the system as well as their views on using this system in daily practice. SETTING: We tested the GRIF system in an experiment in a laboratory setting and in a daily practice trial. STUDY PARTICIPANTS: General practitioners. INTERVENTION: In the laboratory experiment, GPs used the GRIF system to assess the appropriateness of 30 request forms. Each of the GPs was confronted with requests they had submitted to the diagnostic unit of the hospital in the past. In the field trial, the GRIF system was applied during patient consultations for 1 year. MAIN OUTCOME MEASURES: We measured GPs' satisfaction with the system using a questionnaire, and also conducted group discussions (in the laboratory experiment) and in-depth interviews (in the field trial) to elicit GPs' opinions of and experiences with the system. In addition, we explored GPs' reasons for not accepting the comments offered by the GRIF system. RESULTS: The results show that the GPs in the laboratory experiment had more positive attitudes towards the system compared with participants in the field trial. All discussion groups and most of the GPs in the field trial regarded receiving the immediate feedback during the test ordering process as an important advantage. The most frequently mentioned reason to reject the recommendation was disagreement with the content and/or the recommendations in the practice guidelines. CONCLUSION: Apart from securing agreement on guideline content, a prerequisite for using GRIF in daily practice on a large scale is that more attention is paid to promotion of the guidelines and their adoption, and stimulation of a positive attitude towards the practice guidelines among the users.  相似文献   
79.
This qualitative study that allowed children to be the dominant voice examined children's stories of hope. Twenty-nine kindergarten children through to third graders were interviewed using familiar school items: story board, pictures, puppets, and so on. One elementary school, located in a large southwestern metropolitan city, was selected for this study. Data was coded and prominent themes emerged illustrating that children are much more moral than many adults give them credit for. Approximately one-half of the stories shared focused not on the children's wants or “hopes”, but on others - classmates, friends, family, or extended relatives. The findings support research that highlights the issues of care, concern, and compassion that are a priority for young children.  相似文献   
80.
食管贲门癌术后早期肠内营养支持的应用研究   总被引:2,自引:0,他引:2  
目的研究食管贵门癌切除术中放置鼻肠营养管进行早期肠内营养,在维持机体营养、促进恢复履在防治术后并发症的作用。方法将90例管责门癌病人随机分为A、B两组,A组术后常规静脉输液,B组术中放置鼻肠营养管,术后第1天给予肠内营养。两组病人监测术前、术后第10天的体重、肠功能恢复排气时间、疲劳评分,吻合口瘘反感染并发症的发生率。结果两组病人在体重、肠功能恢复方面存在明显差异(P〈0.05),在术后并发症方面差异明显(P〈0.01)。结论鼻肠营养管进行早期肠内营养具有易于维持机体营养,促进机体康复,尽快恢复正氮平衡,减少术后并发症的优点。  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