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   772145篇
  免费   45946篇
  国内免费   1588篇
耳鼻咽喉   9433篇
儿科学   23255篇
妇产科学   17018篇
基础医学   124282篇
口腔科学   16814篇
临床医学   73068篇
内科学   146808篇
皮肤病学   15175篇
神经病学   57526篇
特种医学   27808篇
外国民族医学   64篇
外科学   115128篇
综合类   10972篇
现状与发展   2篇
一般理论   418篇
预防医学   59387篇
眼科学   18249篇
药学   57820篇
  7篇
中国医学   1456篇
肿瘤学   44989篇
  2021年   9074篇
  2020年   5473篇
  2019年   8982篇
  2018年   11447篇
  2017年   8423篇
  2016年   9660篇
  2015年   10978篇
  2014年   15405篇
  2013年   21890篇
  2012年   32891篇
  2011年   35582篇
  2010年   20190篇
  2009年   17963篇
  2008年   31749篇
  2007年   34289篇
  2006年   33646篇
  2005年   32933篇
  2004年   31514篇
  2003年   29767篇
  2002年   28341篇
  2001年   24454篇
  2000年   24523篇
  1999年   21153篇
  1998年   8196篇
  1997年   6862篇
  1996年   6503篇
  1995年   6166篇
  1994年   5373篇
  1992年   15631篇
  1991年   16920篇
  1990年   16919篇
  1989年   16573篇
  1988年   15230篇
  1987年   15119篇
  1986年   14079篇
  1985年   13629篇
  1984年   10579篇
  1983年   9087篇
  1982年   5500篇
  1979年   9619篇
  1978年   7113篇
  1977年   5770篇
  1976年   6075篇
  1975年   7067篇
  1974年   7877篇
  1973年   7545篇
  1972年   6935篇
  1971年   6573篇
  1970年   6125篇
  1969年   5638篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
41.
42.
The present narrative review examines the scientific evidence of the biological mechanisms that may link periodontitis and diabetes, as a source of comorbidity. Publications regarding periodontitis and diabetes, in human, animals, and in vitro were screened for their relevance. Periodontal microbiome studies indicate a possible association between altered glucose metabolism in prediabetes and diabetes and changes in the periodontal microbiome. Coinciding with this, hyperglycemia enhances expression of pathogen receptors, which enhance host response to the dysbiotic microbiome. Hyperglycemia also promotes pro-inflammatory response independently or via the advanced glycation end product/receptor for advanced glycation end product pathway. These processes excite cellular tissue destruction functions, which further enhance pro-inflammatory cytokines expression and alteration in the RANKL/osteoprotegerin ratio, promoting formation and activation of osteoclasts. The evidence supports the role of several pathogenic mechanisms in the path of true causal comorbidity between poorly controlled diabetes and periodontitis. However, further research is needed to better understand these mechanisms and to explore other mechanisms.  相似文献   
43.
44.
45.
46.
47.
Evidence continues to grow on potential environmental health hazards associated with engineered nanomaterials (ENMs). While the geno- and cytotoxic effects of ENMs have been investigated, their potential to target the epigenome remains largely unknown. The aim of this study is two-fold: 1) determining whether or not industry relevant ENMs can affect the epigenome in vivo and 2) validating a recently developed in vitro epigenetic screening platform for inhaled ENMs. Laser printer-emitted engineered nanoparticles (PEPs) released from nano-enabled toners during consumer use and copper oxide (CuO) were chosen since these particles induced significant epigenetic changes in a recent in vitro companion study. In this study, the epigenetic alterations in lung tissue, alveolar macrophages and peripheral blood from intratracheally instilled mice were evaluated. The methylation of global DNA and transposable elements (TEs), the expression of the DNA methylation machinery and TEs, in addition to general toxicological effects in the lung were assessed. CuO exhibited higher cell-damaging potential to the lung, while PEPs showed a greater ability to target the epigenome. Alterations in the methylation status of global DNA and TEs, and expression of TEs and DNA machinery in mouse lung were observed after exposure to CuO and PEPs. Additionally, epigenetic changes were detected in the peripheral blood after PEPs exposure. Altogether, CuO and PEPs can induce epigenetic alterations in a mouse experimental model, which in turn confirms that the recently developed in vitro epigenetic platform using macrophage and epithelial cell lines can be successfully utilized in the epigenetic screening of ENMs.  相似文献   
48.
49.
Bowel diseases of prematurity, including necrotizing enterocolitis, are dreaded ailments of neonates. Early diagnosis is difficult, with clinical and radiographic findings often inconclusive. We present a novel use of contrast-enhanced ultrasound in detection of pediatric bowel disease. Early identification of compromised blood flow or an at-risk bowel can be quantitatively detected and monitored. This ability has implications for guidance of emerging therapies, allowing targeting of inflammation. These findings represent an advancement in detection of bowel disease in neonates.  相似文献   
50.
Guidelines and consensus on the management of patients with acne aim to give evidence-based, expert-group recommendations. This review compares current guidelines and consensus articles to provide a compilation of recommendations on the treatment of acne with oral isotretinoin. Ten common, relevant, clinical questions are addressed, based on published recommendations, including the indications of isotretinoin, the proposed daily dose, the cumulative isotretinoin dose and the laboratory monitoring needed. Recommendations on special considerations are also addressed, including the timing of procedures and the question of an association of depression or inflammatory bowel disease with isotretinoin. A major limitation is the use of different classification systems for acne across guidelines. The recommended daily dose ranges from 0.3 to 0.5 mg/kg in the European guidelines to up to 1 mg/kg in the US guidelines. A specific duration of treatment of at least 6 months is only recommended in the European guidelines. All guidelines report the need of strict pregnancy prevention measures. The European, French and US guidelines recommend to monitor for symptoms of depression. Important clinical questions that are inconsistently addressed in guidelines include the age indication, the recommendation for a cumulative dose, the timing of procedures, the association of isotretinoin with IBD, the recommendation for preventing acne flares and for appropriate laboratory monitoring. These topics should be clearly included in the recommendations of guidelines as they are often raised in everyday clinical practice.  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