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   122326篇
  免费   6631篇
  国内免费   153篇
耳鼻咽喉   1847篇
儿科学   5388篇
妇产科学   4048篇
基础医学   17231篇
口腔科学   3090篇
临床医学   8849篇
内科学   23262篇
皮肤病学   3422篇
神经病学   9400篇
特种医学   5224篇
外国民族医学   32篇
外科学   20036篇
综合类   1627篇
一般理论   31篇
预防医学   6291篇
眼科学   3443篇
药学   8796篇
中国医学   326篇
肿瘤学   6767篇
  2018年   999篇
  2017年   893篇
  2016年   1181篇
  2015年   1342篇
  2014年   1750篇
  2013年   2611篇
  2012年   3417篇
  2011年   3497篇
  2010年   2169篇
  2009年   2118篇
  2008年   3560篇
  2007年   3810篇
  2006年   3956篇
  2005年   4034篇
  2004年   3952篇
  2003年   3812篇
  2002年   3758篇
  2001年   7240篇
  2000年   7219篇
  1999年   6075篇
  1998年   1654篇
  1997年   1583篇
  1996年   1352篇
  1995年   1279篇
  1994年   1154篇
  1993年   1174篇
  1992年   3960篇
  1991年   3772篇
  1990年   3749篇
  1989年   3511篇
  1988年   3121篇
  1987年   3056篇
  1986年   2936篇
  1985年   2722篇
  1984年   2052篇
  1983年   1679篇
  1982年   985篇
  1981年   959篇
  1980年   800篇
  1979年   1894篇
  1978年   1411篇
  1977年   1152篇
  1976年   970篇
  1975年   1211篇
  1974年   1261篇
  1973年   1234篇
  1972年   1078篇
  1971年   1007篇
  1970年   901篇
  1969年   802篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
21.
Pregnant women experience physiological and immunological changes which make them more prone to all kind of viral and bacterial infections, this is because they have been considered as vulnerable group if infected by SARS-CoV-2. They could even deploy a severe form of this disease which may require to end pregnancy to improve oxygenation and to safeguard foetal wellbeing the in case the mother situation gets worse. In this scenario, any intervention would require a detailed planning by the whole surgical team, and, specifically, by the anaesthesiologists, in order to guarantee both mother and child wellbeing and to prevent from infections all the healthcare team. We describe the case of 37 week pregnant woman, admitted in our Critical Care Unit with respiratory high flows device support, due to severe respiratory failure due to COVID-19 which needed an urgent caesarean section.  相似文献   
22.
23.
BackgroundLittle is known of possible gender differences in treatment of periampullary tumours and outcome after pancreatoduodenectomy (PD), and the aim of this study was therefore to investigate any variances from national multicentre perspective.MethodsData from the Swedish National Registry for Pancreatic and Periampullary Cancer for all patients diagnosed with a periampullary tumour from 2012 throughout 2017 was collected. The material was analysed in two groups, men and women, for palliative treatment and curative intended resection.ResultsA total of 5677 patients were included, 2906 (51%) men and 2771 (49%) women. Women were older than men, 72 (65–78) years vs. 70 (64–76), p < 0.001. A lesser proportion of women were planned for resection (1131 (41%) vs. 1288 (44%), p = 0.008), but after adjusting for age and tumour location no difference was seen. Postoperative morbidity was equal, but women had significantly better long-term survival than men. The survival was equal for palliative men and women.ConclusionNo gender bias could be established when analysing treatment for periampullary tumours in Sweden, even though less women were offered surgery. Data suggest that even though women were older they tolerate surgery well and hence offering PD at a higher age for women could be suggested.  相似文献   
24.
25.
Increased expression of GLI1, the main Hedgehog signalling pathway effector, is related to unfavourable prognosis and progressive disease of certain breast cancer subtypes. We used conditional transgenic mice induced to overexpress GLI1 in the mammary epithelium either alone or in combination with deletion of one Trp53 allele to address the role of elevated GLI1 expression in breast tumour initiation and progression. Induced GLI1 expression facilitates mammary gland tumour formation and this was further increased upon heterozygous deletion of Trp53. The GLI1-induced primary tumours were of different murine molecular subtypes, including Normal-likeEx, Class8Ex, Claudin-LowEx and Erbb2-likeEx. The gene expression profiles of some of the tumours correlated well with the PAM50 subtypes for human breast cancer. Whole-exome sequencing revealed somatic mutation profiles with only little overlap between the primary tumours. Orthotopically serially transplanted GLI1-induced tumours maintained the main morphological characteristics of the primary tumours for ≥10 generations. Independent of Trp53 status and molecular subtype, the serially transplanted GLI1-induced tumours were able to grow both in the absence of transgenic GLI1 expression and in the presence of the GLI1 inhibitor GANT61. These data suggest that elevated GLI1 expression has a determinant role in tumour initiation; however, additional genetic events are required for tumour progression.  相似文献   
26.
Socio‐economic disadvantage increases exposure to life stressors. Animal research suggests early life stressors impact later neurodevelopment, including myelin developmental growth. To determine how early life disadvantage may affect myelin growth in adolescence and young adulthood, we analysed data from an accelerated longitudinal neuroimaging study measuring magnetisation transfer (MT), a myelin‐sensitive marker, in 288 participants (149 female) between 14 and 25 years of age at baseline. We found that early life economic disadvantage before age 12, measured by a neighbourhood poverty index, was associated with slower myelin growth. This association was observed for magnetization transfer in cortical, subcortical and core white matter regions, and also in key subcortical nuclei. Participant IQ at baseline, alcohol use, body mass index, parental occupation and self‐reported parenting quality did not account for these effects, but parental education did so partially. Specifically, positive parenting moderated the effect of socio‐economic disadvantage in a protective manner. Thus, early socioeconomic disadvantage appears to alter myelin growth across adolescence. This finding has potential translational implications, including clarifying whether reducing socio‐economic disadvantage during childhood, and increasing parental education and positive parenting, promote normal trajectories of brain development in economically disadvantaged contexts.  相似文献   
27.
28.
29.
30.
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