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   2064607篇
  免费   145905篇
  国内免费   4767篇
耳鼻咽喉   29959篇
儿科学   64006篇
妇产科学   60302篇
基础医学   289696篇
口腔科学   60194篇
临床医学   173952篇
内科学   408205篇
皮肤病学   45820篇
神经病学   164784篇
特种医学   82639篇
外国民族医学   749篇
外科学   323265篇
综合类   46529篇
现状与发展   6篇
一般理论   661篇
预防医学   145802篇
眼科学   48452篇
药学   152286篇
  4篇
中国医学   4402篇
肿瘤学   113566篇
  2018年   19067篇
  2015年   18897篇
  2014年   26739篇
  2013年   41084篇
  2012年   54204篇
  2011年   57452篇
  2010年   34557篇
  2009年   33385篇
  2008年   55248篇
  2007年   59739篇
  2006年   60399篇
  2005年   58931篇
  2004年   56950篇
  2003年   55293篇
  2002年   54358篇
  2001年   95441篇
  2000年   98297篇
  1999年   83468篇
  1998年   22837篇
  1997年   20774篇
  1996年   20267篇
  1995年   19008篇
  1994年   17994篇
  1993年   16756篇
  1992年   65020篇
  1991年   62759篇
  1990年   61510篇
  1989年   59851篇
  1988年   55771篇
  1987年   54731篇
  1986年   52573篇
  1985年   50011篇
  1984年   37469篇
  1983年   31899篇
  1982年   19201篇
  1981年   17269篇
  1979年   35730篇
  1978年   25294篇
  1977年   21892篇
  1976年   20047篇
  1975年   22532篇
  1974年   26793篇
  1973年   25821篇
  1972年   24754篇
  1971年   23060篇
  1970年   21981篇
  1969年   20926篇
  1968年   19762篇
  1967年   17989篇
  1966年   16680篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
91.
92.
Abstract

Objective: To understand the origin of extremely high gonadotropin levels in a perimenopausal woman.

Methods: A 52-year-old woman with a 2?months of amenorrhea followed spontaneous menstrual cycles recovery was referred to our outpatient clinic with elevated follicle-stimulating hormone (FSH, 483 mUI/ml), luteinizing hormone (LH, 475 mUI/ml) and prolactin (PRL, 173?ng/ml). She was known to take levosulpiride. The gonadotropin levels did not fit with the clinical features.

Results: A gonadotroph tumor was ruled out. Further analysis confirmed constantly high FSH, LH and PRL levels. The measurements were repeated using different analytical platforms with different results. After serial dilutions, nonlinearity was present suggesting an immunoassay interference. After post-polyethylene glycol recovery, hormone levels appeared in the normal range. Anti-goat antibodies were recognized in the serum of the patient.

Conclusions: This case report shows a case of falsely abnormal high gonadotropin and PRL levels in a woman during menopause transition. In the clinical practice the evaluation of gonadotropin profile is not recommended at this age, but the abnormal levels stimulated further evaluation. An interference in the assay due to anti-goat antibodies resulted in abnormally high level of FSH and LH. A strict collaboration between clinicians and the laboratory is needed, when laboratory findings do not correspond to clinical findings.  相似文献   
93.
94.
95.
96.
97.
98.
Esophageal adenocarcinoma is the fastest rising cancer in the United States. It develops from long‐standing gastroesophageal reflux disease which affects >20% of the general population. It carries a very poor prognosis with 5‐year survival <20%. The disease is known to sequentially progress from reflux esophagitis to a metaplastic precursor, Barrett''s esophagus and then onto dysplasia and esophageal adenocarcinoma. However, only few patients with reflux develop Barrett''s esophagus and only a minority of these turn malignant. The reason for this heterogeneity in clinical progression is unknown. To improve patient management, molecular changes which facilitate disease progression must be identified. Animal models can provide a comprehensive functional and anatomic platform for such a study. Rats and mice have been the most widely studied but disease homology with humans has been questioned. No animal model naturally simulates the inflammation to adenocarcinoma progression as in humans, with all models requiring surgical bypass or destruction of existing antireflux mechanisms. Valuable properties of individual models could be utilized to holistically evaluate disease progression. In this review paper, we critically examined the current animal models of Barrett''s esophagus, their differences and homologies with human disease and how they have shaped our current understanding of Barrett''s carcinogenesis.  相似文献   
99.
Mitochondria are known primarily as the location of the electron transport chain and energy production in cells. More recently, mitochondria have been shown to be signaling centers for apoptosis and inflammation. Reactive oxygen species (ROS) generated as by-products of the electron transport chain within mitochondria significantly impact cellular signaling pathways. Because of the toxic nature of ROS, mitochondria possess an antioxidant enzyme, superoxide dismutase 2 (SOD2), to neutralize ROS. If mitochondrial antioxidant enzymes are overwhelmed during severe infections, mitochondrial dysfunction can occur and lead to multiorgan failure or death. Pseudomonas aeruginosa is an opportunistic pathogen that can infect immunocompromised patients. Infochemicals and exotoxins associated with P. aeruginosa are capable of causing mitochondrial dysfunction. In this work, we describe the roles of SOD2 and mitochondrial ROS regulation in the zebrafish innate immune response to P. aeruginosa infection. sod2 is upregulated in mammalian macrophages and neutrophils in response to lipopolysaccharide in vitro, and sod2 knockdown in zebrafish results in an increased bacterial burden. Further investigation revealed that phagocyte numbers are compromised in Sod2-deficient zebrafish. Addition of the mitochondrion-targeted ROS-scavenging chemical MitoTEMPO rescues neutrophil numbers and reduces the bacterial burden in Sod2-deficient zebrafish. Our work highlights the importance of mitochondrial ROS regulation by SOD2 in the context of innate immunity and supports the use of mitochondrion-targeted ROS scavengers as potential adjuvant therapies during severe infections.  相似文献   
100.
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