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   932820篇
  免费   67716篇
  国内免费   1356篇
耳鼻咽喉   12961篇
儿科学   24390篇
妇产科学   23280篇
基础医学   133329篇
口腔科学   28300篇
临床医学   80637篇
内科学   183653篇
皮肤病学   19261篇
神经病学   72390篇
特种医学   36871篇
外国民族医学   79篇
外科学   152598篇
综合类   18051篇
现状与发展   1篇
一般理论   234篇
预防医学   61704篇
眼科学   21350篇
药学   72806篇
  3篇
中国医学   2167篇
肿瘤学   57827篇
  2018年   9009篇
  2017年   7082篇
  2016年   7814篇
  2015年   8908篇
  2014年   12042篇
  2013年   17595篇
  2012年   24241篇
  2011年   25206篇
  2010年   14910篇
  2009年   14361篇
  2008年   24764篇
  2007年   25854篇
  2006年   26646篇
  2005年   25576篇
  2004年   24685篇
  2003年   23726篇
  2002年   23274篇
  2001年   54786篇
  2000年   56609篇
  1999年   47017篇
  1998年   10780篇
  1997年   9498篇
  1996年   9626篇
  1995年   8957篇
  1994年   8301篇
  1993年   7615篇
  1992年   35532篇
  1991年   33951篇
  1990年   32773篇
  1989年   31921篇
  1988年   29022篇
  1987年   28281篇
  1986年   26309篇
  1985年   25180篇
  1984年   17853篇
  1983年   15161篇
  1982年   7807篇
  1981年   6777篇
  1979年   15791篇
  1978年   10607篇
  1977年   9058篇
  1976年   7874篇
  1975年   8635篇
  1974年   10467篇
  1973年   9865篇
  1972年   9368篇
  1971年   8854篇
  1970年   8433篇
  1969年   7928篇
  1968年   7207篇
排序方式: 共有10000条查询结果,搜索用时 46 毫秒
141.
Schizophrenia is a chronic and severe psychiatric disorder that has profound impact on an individual’s life and on society. Thus, developing more effective therapeutic interventions is essential. Over the past quarter‐century, an abundance of evidence from pharmacologic challenges, post‐mortem studies, brain imaging, and genetic studies supports the role of glutamatergic dysregulation in the pathophysiology of schizophrenia, and the results of recent randomized clinical trials based on this evidence have yielded promising results. In this article, we review the evidence that alterations in glutamatergic neurotransmission, especially focusing on the N‐methyl‐d ‐aspartate receptor (NMDAR) function, may be a critical causative feature of schizophrenia, how this contributes to pathologic circuit function in the brain, and how these insights are revealing whole new avenues for treatment development that could reduce treatment‐resistant symptoms, which account for persistent disability.  相似文献   
142.
This paper reviews the published literature on a group of developmental disorders of the retina and retinal pigment epithelium which result in focal abnormalities in one or both eyes. They are often asymptomatic, found on routine examination and are generally non-progressive. Some are associated with other systemic abnormalities.Subject terms: Retinal diseases, Eye abnormalities  相似文献   
143.
Congenital heart disease is a rare but important finding in adults who experience sudden death. Examination of the congenitally malformed heart has historically been considered esoteric and best left to those with expertise. The Cardiac Risk in the Young cardiovascular pathology laboratory based at St George's University of London has now received over 6,000 cases. Of these, 21 congenitally malformed hearts were retained for research and educational purposes. Hearts were assessed using sequential segmental analysis, and causes of death were adjudicated based on thorough macroscopic examination and histology. Congenital malformations that were encountered included atrial septal defects, ventricular septal defects, tetralogy of Fallot, and transposition of the great arteries in both its regular and congenitally corrected variants. Findings also included hearts with mirror-imaged and isomeric atrial appendages. Direct causes of death included myocardial fibrosis, pulmonary hypertension, and hemorrhage. A small but notable proportion did not reveal a substrate for arrhythmia, raising the question of whether the terminal event was due to the congenital heart disease itself, or an underlying channelopathy. Here, we demonstrate the value of simple sequential segmental analysis in describing and categorizing the cases, with the concept of the “morphological method” serving to identify the distinguishing features of the cardiac components. Clin. Anat. 33:394–404, 2020. © 2019 Wiley Periodicals, Inc.  相似文献   
144.
145.
146.
We present the case of a 54‐year‐old patient with renal transplant who developed unusual vascular changes on the forearm distal to a functioning arteriovenous fistula, as well as a painful ulcerated lesion on her anterior abdominal wall. We believe that the diffuse dermal angioendotheliomatosis variant of reactive angioendotheliomatosis had a role in the pathogenesis of this patient's lesions.  相似文献   
147.
148.
149.
150.
Drug design and discovery studies are important because of the prevalence of diseases without available medical cures. New anticancer agents are particularly urgent because of the high mortality rate associated with cancer. A series of mononuclear gold (III) and platinum (II) complexes based on boronated phenylalanine (BPA) were designed and synthesized using 4,4’-dimethyl-2,2’-dipyridyl (L1) or 1,10-phenanthroline-5,6-dion (L2) ligands to obtain promising anticancer drug candidates. Proton nuclear magnetic resonance, infrared, mass spectrometry, and elemental analyses were utilized for chemical characterizations. Cell viability, cancer cell colony formation, endothelial tube formation, and cytoskeleton staining assays were performed using A549 lung adenocarcinoma and human umbilical vein endothelial cells (HUVECs) to investigate preliminary pharmacological activities. L1-based platinum (II) complex (BPA-L1-Pt) was the most promising complex, and has similar activity with the approved chemotherapy drug cis-platinum. Half maximal inhibitory concentration values for BPA-L1-Pt were 9.15 µM on A549s and 16.61 µM on HUVECs; the values for cis-platinum were 5.24 µM on A549s and 23.14 µM on HUVECs. Consequently, further synthesis studies should be performed to boost the cancer cell selectivity feature of BPA by varying metal and ligand types.  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