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   2538篇
  免费   367篇
  国内免费   199篇
耳鼻咽喉   9篇
儿科学   82篇
妇产科学   18篇
基础医学   343篇
口腔科学   191篇
临床医学   119篇
内科学   1035篇
皮肤病学   36篇
神经病学   153篇
特种医学   8篇
外科学   89篇
综合类   141篇
现状与发展   4篇
预防医学   444篇
眼科学   17篇
药学   184篇
中国医学   127篇
肿瘤学   104篇
  2024年   15篇
  2023年   212篇
  2022年   220篇
  2021年   511篇
  2020年   412篇
  2019年   273篇
  2018年   197篇
  2017年   216篇
  2016年   160篇
  2015年   151篇
  2014年   187篇
  2013年   258篇
  2012年   76篇
  2011年   44篇
  2010年   22篇
  2009年   24篇
  2008年   19篇
  2007年   10篇
  2006年   10篇
  2005年   14篇
  2004年   7篇
  2003年   5篇
  2002年   8篇
  2001年   5篇
  2000年   4篇
  1999年   5篇
  1998年   4篇
  1997年   4篇
  1996年   2篇
  1995年   3篇
  1994年   3篇
  1993年   1篇
  1992年   2篇
  1991年   5篇
  1989年   3篇
  1988年   4篇
  1987年   1篇
  1986年   1篇
  1985年   2篇
  1984年   1篇
  1979年   3篇
排序方式: 共有3104条查询结果,搜索用时 20 毫秒
21.
Clostridium difficile has been documented as a major cause of uncontrolled outbreaks of enteritis in neonatal pigs and antibiotic-associated infections in clinical settings. It belongs to the natural cohort of early colonisers of the gastrointestinal tract of pigs and can be detected in faeces up to two weeks post-partum. In older pigs, it often remains under the detection limit. Most neonatal pigs show no clinical signs of disease although C. difficile and its toxins can be detected at high levels in faeces. Increased mortality rates associated with C. difficile on pig farms are, so far, considered “spontaneous” and the predisposing factors are mostly not defined. The infection caused by C. difficile is multifactorial and it is likely that the repertoire of maternal factors, host physiology, the individually developing gut microbiota, co-infections and environmental stress define the conditions for disease development. In this addendum to our recently published work on CDI in neonatal piglets, we discuss the “early-life events” that influence C. difficile spread and infection in neonatal piglets.  相似文献   
22.
23.
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   
24.
ObjectiveAn aberrant gut microbiota may be associated with a broad spectrum of diseases including mental illness. The gut microbiota is scarcely studied in bipolar disorder (BD). We examined the gut microbiota composition in patients with newly diagnosed BD, their unaffected first-degree relatives and healthy individuals.MethodsStool samples were collected from 113 patients with BD, 39 unaffected first-degree relatives and 77 healthy individuals and the microbiota was profiled using 16S rRNA gene amplicon sequencing.ResultsThe gut microbiota community membership of patients with BD differed from that of healthy individuals (R2 = 1.0%, P = 0.008), whereas the community membership of unaffected first-degree relatives did not. Flavonifractor was present in 61% of patients with BD, 42% of their unaffected relatives and 39% of healthy individuals. Presence of Flavonifractor was associated with an odds ratio of 2.9 (95%CI: 1.6–5.2, P = 5.8 × 10−4, Q = 0.036) for having BD. When excluding smokers, presence of Flavonifractor was associated with an odds ratio of 2.3 (95%CI: 1.1–5.3, P = 0.019) for having BD. However, when considering the subsample of non-smokers only, BD and presence of Flavonifractor were no longer associated when adjusted for all possible tests at genus level (Q = 0.6). Presence of Flavonifractor in patients with BD was associated with smoking and female sex, but not with age, waist circumference, exercise level, high-sensitive C-reactive protein, current affective state, subtype of BD, illness duration or psychotropic medication, respectively.ConclusionFlavonifractor, a bacterial genus that may induce oxidative stress and inflammation in its host, was associated with BD. Higher prevalence of smoking among patients with BD contributed to our findings, and it cannot be excluded that findings are influenced by residual confounding.  相似文献   
25.
The prevalence of colorectal cancer (CRC) has markedly increased worldwide in the last decade. Alterations of bile acid metabolism and gut microbiota have been reported to play vital roles in intestinal carcinogenesis. About trillions of bacteria have inhabited in the human gut and maintained the balance of host metabolism. Bile acids are one of numerous metabolites that are synthesized in the liver and further metabolized by the gut microbiota, and are essential in maintaining the normal gut microbiota and lipid digestion. Multiple receptors such as FXR, GPBAR1, PXR, CAR and VDR act as sensors of bile acids have been reported. In this review, we mainly discussed interplay between bile acid metabolism and gut microbiota in intestinal carcinogenesis. We then summarized the critical role of bile acids receptors involving in CRC, and also addressed the rationale of multiple interventions for CRC management by regulating bile acids–microbiota axis such as probiotics, metformin, ursodeoxycholic acid and fecal microbiota transplantation. Thus, by targeting the bile acids–microbiota axis may provide novel therapeutic modalities in CRC prevention and treatment.  相似文献   
26.
27.
中枢神经系统疾病除了神经系统相关症状外,常伴随胃肠道症状,在不同疾病患者体内可观察到相应肠道菌群失调现象。肠道菌群及代谢产物可通过外周神经、免疫等途径参与中枢神经系统活动,肠道菌群失调与阿尔兹海默病、帕金森病、肌萎缩性脊髓侧索硬化、多发性硬化等多种中枢神经系统疾病的发生发展密切相关,有研究证明,模型动物或患者在接受粪菌移植治疗后症状改善。该文就粪菌移植治疗中枢神经系统疾病中的研究进展进行综述。  相似文献   
28.
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   
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