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   126970篇
  免费   7722篇
  国内免费   1034篇
耳鼻咽喉   1386篇
儿科学   3742篇
妇产科学   3263篇
基础医学   16518篇
口腔科学   3032篇
临床医学   10018篇
内科学   29283篇
皮肤病学   2569篇
神经病学   12334篇
特种医学   5058篇
外国民族医学   25篇
外科学   18157篇
综合类   1721篇
一般理论   53篇
预防医学   6748篇
眼科学   1921篇
药学   9603篇
  3篇
中国医学   563篇
肿瘤学   9729篇
  2023年   587篇
  2022年   1151篇
  2021年   2625篇
  2020年   1666篇
  2019年   2303篇
  2018年   2890篇
  2017年   2254篇
  2016年   2480篇
  2015年   2827篇
  2014年   3694篇
  2013年   5193篇
  2012年   7291篇
  2011年   7511篇
  2010年   4691篇
  2009年   4210篇
  2008年   6764篇
  2007年   6831篇
  2006年   6521篇
  2005年   6236篇
  2004年   6500篇
  2003年   6165篇
  2002年   6064篇
  2001年   3979篇
  2000年   3861篇
  1999年   3250篇
  1998年   1427篇
  1997年   1151篇
  1996年   1060篇
  1995年   983篇
  1994年   856篇
  1993年   850篇
  1992年   1950篇
  1991年   1883篇
  1990年   1620篇
  1989年   1554篇
  1988年   1419篇
  1987年   1291篇
  1986年   1269篇
  1985年   1104篇
  1984年   878篇
  1983年   769篇
  1982年   520篇
  1981年   453篇
  1980年   424篇
  1979年   605篇
  1978年   457篇
  1975年   445篇
  1974年   509篇
  1973年   483篇
  1972年   439篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
1.
It is well recognized that the world population is ageing rapidly. Therefore, it is important to understand ageing processes at the cellular and molecular levels to predict the onset of age‐related diseases and prevent them. Recent research has focused on the identification of ageing biomarkers, including those associated with the properties of the Golgi apparatus. In this context, Golgi‐mediated glycosylation of proteins has been well characterized. Additionally, other studies show that the secretion of many compounds, including pro‐inflammatory cytokines and extracellular matrix–degrading enzymes, is modified during ageing, resulting in physical and functional skin degradation. Since the Golgi apparatus is a central organelle of the secretory pathway, we investigated its structural organization in senescent primary human dermal fibroblasts using confocal and electron microscopy. In addition, we monitored the expression of Golgi‐related genes in the same cells. Our data showed a marked alteration in the Golgi morphology during replicative senescence. In contrast to its small and compact structure in non‐senescent cells, the Golgi apparatus exhibited a large and expanded morphology in senescent fibroblasts. Our data also demonstrated that the expression of many genes related to Golgi structural integrity and function was significantly modified in senescent cells, suggesting a relationship between Golgi apparatus function and ageing.  相似文献   
2.
Purpose: To use polymerase chain reaction (PCR) and Goldmann-Witmer coefficient (GWC) calculation to diagnose infectious uveitis.

Methods: Prospective cross-sectional study.

Results: Twenty-seven of 106 patients had positive PCR and/or GWC results on aqueous humor (AH) sampling and 15 of 27 (55.6%) were HIV-positive. Patients with non-anterior uveitis (NAU) were more likely to be HIV+ (p = 0.005). More than 1 possible pathogen was identified in 9 of 27 patients of whom 7 were HIV+. The final clinical diagnosis was discordant with AH findings in 9 of 27 cases. A positive EBV PCR result was associated with a discordant diagnosis (p = 0.001). All cases of herpetic anterior uveitis (42.9% HIV+) tested PCR-/GWC+ while all cases of herpetic NAU tested PCR+/GWC- (83.3% HIV+). All rubella virus cases were PCR+/GWC+.

Conclusion: PCR is useful to diagnose herpetic NAU in HIV+ patients while GWC is useful to diagnose herpetic anterior uveitis.  相似文献   

3.
4.
With easy chemical synthesis from its precursor, methamphetamine (MA) is now widespread in many countries. The abuse of methamphetamine is associated with several negative effects on health, because MA is a neurotoxin and a dangerous central nervous system stimulant. It changes levels of neurotransmitters in the brain, releasing dopamine and inhibiting nor epinephrine uptake which increases sympathetic nervous system activity and can lead to cardiac arrhythmia, hypertension and tachypnea. The consequences of MA abuse are clearly manifested in oral diseases (like “meth mouth”) which is characterised by extensive caries, teeth grinding with ensuing dental wear and trismus. The present review was designed to fill the gap in knowledge about methamphetamine abuse in the European Union (EU) and to illustrate the main clinical effects of prolonged use. After describing the pharmacology and systemic effects of methamphetamine and concentrating on its effects on the mouth, the present review compares the epidemiology and incidence of abuse in the world, particularly the USA and the EU. Key words:Methamphetamine, “Meth mouth”, drug abuse, oral health.  相似文献   
5.
6.
7.
8.
9.
10.
ABSTRACT

Purpose

To investigate the expression of IL-11 and its receptor IL-11Rα and to quantify density of CD163+ M2 macrophages in proliferative diabetic retinopathy (PDR).  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