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   3768篇
  免费   638篇
  国内免费   188篇
耳鼻咽喉   21篇
儿科学   24篇
妇产科学   34篇
基础医学   391篇
口腔科学   44篇
临床医学   401篇
内科学   331篇
皮肤病学   39篇
神经病学   110篇
特种医学   211篇
外科学   536篇
综合类   969篇
现状与发展   1篇
预防医学   291篇
眼科学   70篇
药学   406篇
  29篇
中国医学   466篇
肿瘤学   220篇
  2024年   29篇
  2023年   210篇
  2022年   516篇
  2021年   426篇
  2020年   402篇
  2019年   203篇
  2018年   177篇
  2017年   121篇
  2016年   215篇
  2015年   325篇
  2014年   617篇
  2013年   518篇
  2012年   244篇
  2011年   133篇
  2010年   107篇
  2009年   97篇
  2008年   44篇
  2007年   35篇
  2006年   34篇
  2005年   25篇
  2004年   9篇
  2003年   11篇
  2002年   7篇
  2001年   9篇
  2000年   5篇
  1999年   3篇
  1998年   6篇
  1997年   8篇
  1996年   15篇
  1995年   10篇
  1994年   3篇
  1993年   5篇
  1992年   1篇
  1991年   1篇
  1990年   1篇
  1989年   7篇
  1988年   7篇
  1987年   3篇
  1986年   5篇
排序方式: 共有4594条查询结果,搜索用时 15 毫秒
51.
Y-chromosomal SNP (Y-SNP), with its stable inheritance and low mutation, can provide Supplementary information in forensic investigation. While commonly used Y-chromosomal STR haplotypes show their limitations, typing of Y-SNP would become a powerful complement. In this study, a 16-plex Y-SNP typing system based on allele-specific PCR (AS-PCR) was developed to discriminate four dominant Y-chromosomal haplogroups (C-M130, D-CTS3946, N-M231, and O-M175) and 12 predominant sub-haplogroups of O-M175 (O1a-M119, O1a1a1a-CTS3265, O1b-M268, O1b1a2-Page59, O2-M122, O2a1-L127.1, O2a1b-F240, O2a1b1a1-CTS5820, O2a2-P201, O2a2b1a1-M177, O2a2b1a1a1a-Y17728, O2a2b1a2-F114). A series of experimental validation studies including sensitivity, species specificity, male-female mixture and inhibition were performed. The discrimination of the typing system was preliminarily proved with a haplogroup diversity of 0.9239. Altogether, the Y-SNP typing system based on AS-PCR should be capable of distinguishing China’s dominant Y-chromosomal haplogroups in a rapid and reliable manner, thus can be employed as a useful complement in forensic casework.  相似文献   
52.
帕金森病是以多巴胺能神经元减少导致的以静止性震颤、肌强直、运动迟缓和姿势步态障碍为主要临床症状的疾病。此病是蒙医白脉病的一种,又称彻彻热乎病。蒙医将人体的脉络分为白脉和黑脉。白脉病是白脉系统遭受致病因素的影响后所致的一系列疾病的总称,临床上很多疾病归属于“白脉病”。为更好的实现对蒙医优势单病种的规范化研究,本文基于白脉理论,探析蒙医对帕金森病的认识,以期为未来的研究提供理论支持。  相似文献   
53.
目的对于复杂创伤骨科教学工作中应用3D打印技术的应用价值进行探讨。方法选取2018年1月-2019年1月本科学生60名作为此次研究对象,根据随机数字表法对所选60名学生加以分组,其中30名学生接受传统教学方案,将其作为对照组,剩余30名学生接受3D打印技术教学,将其作为研究组,对比两组学生接受不同教学方案之后的教学成绩。结果除专业兴趣程度外,两组学生接受不同教学方案之后的自我认知能力以及出科考试成绩对比差异有统计学意义(P<0.05)。结论针对复杂创伤骨科教学工作中应用3D打印技术效果理想,能够帮助教学工作顺利完成,显著提高学生动作操作能力,使学生良好的掌握复杂创伤骨科知识。  相似文献   
54.
55.
Recently, 2-aminothiazoline-4-carboxylic acid (ATCA), a cyanide (CN) metabolite, has been proposed as a stable diagnostic marker of CN poisoning. In this study, liquid chromatography coupled with electrospray ionization – tandem mass spectrometry was used to quantify ATCA concentrations in human postmortem blood samples, and differences in ATCA concentrations according to age and sex were determined. Both age and sex had significant effects on blood ATCA concentrations. Although ATCA concentrations exhibited an inverted U shape with increasing age in men, in women ATCA concentrations plateaued at around 40–59 years of age. There were significant differences between the sexes in ATCA concentrations for the 20–39 and 40–59 year age groups (P < 0.05 and P < 0.01, respectively). Correlations between ATCA concentrations and carboxyhemoglobin (CO-Hb) saturation were also examined in fire victims. ATCA concentrations increased significantly with increasing CO-Hb saturation (r = 0.382, P < 0.01). In addition, ATCA concentrations were also correlated to CN concentrations (r = 0.309, P < 0.05). The results of our study may provide novel information about the contribution of CN poisoning to the cause of death at fire scenes.  相似文献   
56.
Essential polyunsaturated fatty acids (PUFA) from the n-3 and n-6 series constitute the building blocks of brain cell membranes where they regulate most aspects of cell physiology. They are either biosynthesized from their dietary precursors or can be directly sourced from the diet. An overall increase in the dietary n-6/n-3 PUFA ratio, as observed in the Western diet, leads to reduced n-3 PUFAs in tissues that include the brain. Some clinical studies have shown a positive correlation between dietary n-3 PUFA intake and sleep quantity, yet evidence is still sparse. We here used a preclinical model of dietary n-3 PUFA deficiency to assess the precise relationship between dietary PUFA intake and sleep/wake activity. Using electroencephalography (EEG)/electromyography (EMG) recordings on n-3 PUFA deficient or sufficient mice, we showed that dietary PUFA deficiency affects the architecture of sleep-wake activity and the oscillatory activity of cortical neurons during sleep. In a second part of the study, and since PUFAs are a potent modulator of inflammation, we assessed the effect of dietary n-3 PUFA deficiency on the sleep response to an inflammatory stimulus known to modulate sleep/wake activity. We injected mice with the endotoxin lipopolysaccharide (LPS) and quantified the sleep response across the following 12 h. Our results revealed that n-3 PUFA deficiency affects the sleep response in basal condition and after a peripheral immune challenge. More studies are now required aimed at deciphering the molecular mechanisms underlying the intimate relationship between n-3 PUFAs and sleep/wake activity.  相似文献   
57.
58.
59.
阐述恶性肿瘤流行现状、生存质量的概念及评定方法,综述恶性肿瘤病人生存质量现状及影响因素,为提高恶性肿瘤病人生存质量提供理论依据。  相似文献   
60.
患者女,35岁。全身红色皮疹伴发热2个月,上半身皮疹加重20d。查体:面颈部及双上肢环状红斑,双手震颤,突眼,甲状腺肿大;ANA1∶160,SSA3(+);T4,FT4↑,TSH↓,TG-Ab,TPO-Ab↑;甲状腺彩超示:甲状腺弥漫性肿大,血流丰富。皮损组织病理示:表皮变薄,基底液化变性,真皮浅层血管及附属器周围局灶性淋巴细胞为主的炎细胞浸润,可见个别噬黑素细胞,胶原轻度嗜碱变性。诊断:SCLE合并甲亢。SCLE合并甲亢尚未见报道,可能与两者有相同的遗传及免疫学基础有关。  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