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   3437篇
  免费   391篇
  国内免费   287篇
耳鼻咽喉   10篇
儿科学   101篇
妇产科学   24篇
基础医学   498篇
口腔科学   192篇
临床医学   184篇
内科学   1307篇
皮肤病学   41篇
神经病学   202篇
特种医学   13篇
外科学   204篇
综合类   201篇
现状与发展   4篇
预防医学   608篇
眼科学   19篇
药学   231篇
中国医学   145篇
肿瘤学   131篇
  2024年   22篇
  2023年   244篇
  2022年   288篇
  2021年   649篇
  2020年   459篇
  2019年   330篇
  2018年   234篇
  2017年   243篇
  2016年   192篇
  2015年   175篇
  2014年   240篇
  2013年   302篇
  2012年   108篇
  2011年   74篇
  2010年   55篇
  2009年   57篇
  2008年   61篇
  2007年   45篇
  2006年   47篇
  2005年   37篇
  2004年   35篇
  2003年   23篇
  2002年   18篇
  2001年   14篇
  2000年   11篇
  1999年   19篇
  1998年   13篇
  1997年   14篇
  1996年   11篇
  1995年   8篇
  1994年   9篇
  1993年   4篇
  1992年   6篇
  1991年   9篇
  1990年   6篇
  1989年   7篇
  1988年   7篇
  1987年   4篇
  1986年   5篇
  1985年   3篇
  1984年   2篇
  1983年   3篇
  1982年   2篇
  1981年   4篇
  1979年   4篇
  1978年   2篇
  1977年   3篇
  1976年   3篇
  1968年   1篇
  1907年   1篇
排序方式: 共有4115条查询结果,搜索用时 15 毫秒
1.
Gut bacteria and gut barrier plays important roles in body homeostasis. Ciprofloxacin (CPFX) is widely used to treat bacterial infections. However, whether high dosage of CPFX has side effects on gut barrier integrity is still unclear. Our results indicated that the High CPFX treatment (1 mg/ml) caused weight loss, nervousness, anorexia, and increased apoptosis cells in gut, but less influence was observed in the Low CPFX group (0.2 mg/ml). Meanwhile, the High CPFX treatment impaired tight junction molecules Ocln/ZO-1 level and down-regulated antibacterial genes expression (reg3γ, pla2g2α and defb1). Further, the High CPFX treatment increased pro-inflammatory cytokine IL-1β in intestinal tract, decreased IL-17A of duodenum but increased IL-17A of colon at day 37. In addition, the gut bacterial diversity and richness behaved significantly loss regarding CPFX treatment, especially in the High CPFX group during the experiment. Indole exhibited sharply decline in both Low and High CPFX groups at day 7, and the High CPFX mice needed longer time on restoring indole level. Meanwhile, CPFX treatment strongly decreased the concentrations of butyric acid and valeric acid at day 1. Correlation analysis indicated that the linked patterns between the key bacteria (families Bacteroidales_S247, Ruminococcaceae and Desulfovibrionaceae) and metabolites (indole and butyric acid) were disturbed via the CPFX treatment. In conclusion, the High CPFX treatment impaired the gut barrier with the evidence of reduced expression of tight junction proteins, increased apoptosis cells and inflammatory cells, decreased the bacterial diversity and composition, which suggesting a proper antibiotic-dosage use should be carefully considered in disease treatment.  相似文献   
2.
3.
人类微生物群是由寄生在人体上皮屏障的细菌和其他微生物组成的,其中大部分位于肠道内,与宿主之间形成共生的关系。机体肠道微生物的组成虽然受到年龄、饮食、生活方式等因素的影响,但在正常生理情况下是相对稳定的。近年来,肠道菌群与恶性肿瘤的关系越来越受到重视。肠道菌群不但能够维持局部稳态,还能调节机体代谢、炎症和免疫等生理过程。有研究表明,微生物群,特别是肠道菌群能够显著调节机体对癌症治疗的反应性以及机体对毒副反应的敏感性。检查肠道菌群中各菌种之间的比例可作为筛查恶性肿瘤的新方法。本文将综述微生物群具有影响肿瘤的发生发展、抗肿瘤治疗疗效以及药物不良反应的证据,以及其中所涉及的微生物种类,从而为恶性肿瘤精准治疗提供证据。  相似文献   
4.
5.
6.
7.
8.
工作相关肌肉骨骼疾患(WMSDs)是常见的慢性非传染性疾病。WMSDs已成为影响工人健康、降低工人生命质量和造成经济损失的重要因素,可见于多个行业、工种。本文对WMSDs流行现状及人体工效学负荷相关研究进行综述,以期找到职业人群保护的可行方法。  相似文献   
9.
ABSTRACT

Although exclusive breastfeeding has been linked to lower rates of postnatal HIV transmission compared to nonexclusive breastfeeding, mechanisms underlying this are unclear. Across a longitudinally sampled cohort of South African infants, we showed that exclusively breastfed (EBF) infants had altered gut bacterial communities when compared to nonexclusively breastfed (NEBF) infants, as well as reduced peripheral CD4 + T cell activation and lowered chemokine and chemokine receptor expression in the oral mucosa. We further demonstrated that the relative abundance of key taxa was correlated with peripheral CD4 + T cell activation. Here, we supplement those findings by using compositional data analyses to identify shifts in the abundance of several Bifidobacteria strains relative to select strains of Escherichia, Bacteroides, and others that are associated with the transition to NEBF. We illustrate that the abundance ratio of these taxa is tightly correlated with feeding modality and is a strong predictor of peripheral T cell activation. More broadly, we discuss our study in the context of novel developments and explore future directions for the field.  相似文献   
10.
Non alcoholic fatty liver disease or NAFLD is a disease with a large spectrum of liver injury that could appear in overweight or obese individuals with a metabolic syndrome. However, among overweight or obese, only a subset of individuals develops severe forms of NAFLD. Thus, the susceptibility of NAFLD is related to cofactors that could be protective or conversely noxious. Studies carried out in rodent models have demonstrated that the intestinal microbiota is a cofactor with a causal role in NAFLD. The bacterial patterns as well as the metabolites produced by intestinal bacteria are directly involved in the mediation of their effects, although the mechanisms are far from being fully identified. Changing intestinal microbiota by using fibers, prebiotics or probiotics can prevent or improve NAFLD in murine models. The translation of these data to human therapeutics is encouraging but remains limited. Indeed, there is clearly a dysbiosis associated with the different stages of NAFLD. The first clinical trials performed in patients to improve NAFLD showed beneficial effects although their analysis remains complicated given the many confounding factors, such as the use of metformin or proton inhibitors. A first clinical trial using a metabolite from Akkermansia muciniphila, suggests that new therapeutic approaches will emerge in the coming years based either on the modulation of the intestinal microbiota directly or on the modulation of intestinal microbiota targets.  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