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   543381篇
  免费   35552篇
  国内免费   26050篇
耳鼻咽喉   3955篇
儿科学   11366篇
妇产科学   7105篇
基础医学   56672篇
口腔科学   7641篇
临床医学   64886篇
内科学   80448篇
皮肤病学   4764篇
神经病学   33967篇
特种医学   22532篇
外国民族医学   224篇
外科学   61233篇
综合类   71815篇
现状与发展   86篇
一般理论   31篇
预防医学   45199篇
眼科学   13342篇
药学   49595篇
  436篇
中国医学   24937篇
肿瘤学   44749篇
  2024年   1281篇
  2023年   5464篇
  2022年   14416篇
  2021年   18341篇
  2020年   14451篇
  2019年   11804篇
  2018年   33038篇
  2017年   28267篇
  2016年   29491篇
  2015年   17679篇
  2014年   21696篇
  2013年   19759篇
  2012年   35023篇
  2011年   52069篇
  2010年   39630篇
  2009年   28629篇
  2008年   40330篇
  2007年   42312篇
  2006年   20586篇
  2005年   21299篇
  2004年   15896篇
  2003年   16416篇
  2002年   12399篇
  2001年   8783篇
  2000年   8714篇
  1999年   8542篇
  1998年   5490篇
  1997年   5288篇
  1996年   4040篇
  1995年   3808篇
  1994年   3226篇
  1993年   2081篇
  1992年   2460篇
  1991年   2207篇
  1990年   1912篇
  1989年   1629篇
  1988年   1333篇
  1987年   1220篇
  1986年   976篇
  1985年   704篇
  1984年   387篇
  1983年   291篇
  1982年   166篇
  1981年   169篇
  1980年   153篇
  1979年   156篇
  1978年   81篇
  1974年   61篇
  1938年   62篇
  1932年   61篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
31.
32.
33.
34.
35.
For persons battling HIV/AIDS a stable place to live may decide the length and quality of life itself. It is nearly impossible for a person on the streets to engage in a needed continuous AIDS treatment regimen when the very basic question of where that person will rest his or her head when darkness comes in just a few hours is unresolved. When danger lurks on the streets, when cold numbs the limbs, when tiredness overwhelms the mind, when fear breaks the spirit, a place to call home would make all the difference.  相似文献   
36.
X Dong  M He  X Song  B Lu  Y Yang  S Zhang  N Zhao  L Zhou  Y Li  X Zhu  R Hu 《Diabetic medicine》2007,24(12):1482-1486
AIMS: Our aim was to assess performances of the Cockcroft-Gault and simplified Modification of Diet in Renal Disease (MDRD) formulae in estimating glomerular filtration rate (GFR) in Chinese diabetic populations and their association with vascular risks. METHODS: A total of 1009 patients with Type 2 diabetes were categorized into low estimated GFR groups (GFR < 60 ml/min/1.73 m(2)) and control groups by the two equations. The performances of these formulae were assessed at different stages of kidney function. Carotid artery intima-media thickness (IMT) and the prevalence of diabetic retinopathy or albuminuria were compared among the groups. The ability of these formulae to identify established vascular risk markers using sensitivity, specificity, positive and negative predictive values were also compared. RESULTS: The prevalence of low estimated GFR was 32.7% with the Cockcroft-Gault formula and 5.2% with the MDRD formula, respectively. In low estimated GFR subjects by the MDRD formula, IMT was significantly thicker than those by the Cockcroft-Gault formula (1.2 mm vs. 1.0 mm; P < 0.05), with a higher prevalence of albuminuria (78.4 vs. 52.8%, P < 0.05) and diabetic retinopathy (46.5 vs. 30.5%; P < 0.05). The Cockcroft-Gault formula gave a specificity of 71.7% and a sensitivity of 37.0%, and the MDRD formula gave a specificity of 96.6% and a sensitivity of 7.9% in estimating low GFR relevant for established vascular risks. CONCLUSIONS: These formulae performed differently in Chinese diabetic populations. The simplified MDRD formula is minimally superior to the Cockcroft-Gault formula for its high specificity and positive predictive values in estimating low GFR relevant for vascular risks.  相似文献   
37.
38.
BACKGROUND: The ubiquitin-proteasome system (UPS) is thought to be functionally active in atherosclerosis (AS) lesions. Aspirin was found to be a potent inhibitor of the UPS in some tumour studies; however, its effect on AS remains to be demonstrated in vivo. METHODS: New Zealand rabbits were placed on a normal diet (N) or on a normal diet with aspirin (NI) or on an atherogenic diet without (H) or with aspirin (HI) for 12 weeks. Proteasome activity, concentrations of plasma lipids and levels of peroxidation were determined. Ubiquitin/ubiquitin-conjugates (Ub), IkappaBalpha, phosphorylated IkappaB (pIkappaBalpha) and p65 were investigated by Western blotting or immunochemistry. RESULTS: Concentrations of plasma lipids and peroxidation levels were higher in H or HI vs. N or NI. Histological analysis showed that atheroma was increased in H. Ub and IkappaBalpha were mainly localised in subendothelium and media vascular smooth muscle cells. Western blots revealed that Ub, IkappaBalpha, and pIkappaBalpha were increased, whereas p65 was lower in HI vs. H. The activity of the 20S proteasome was functionally active in H vs. N, NI or HI, while the 26S proteasome was not affected in any of the groups. CONCLUSIONS: Aspirin can attenuate the pathogenesis of atheroma formation, the degradation of IkappaBalpha and pIkappaBalpha, and lower the expression of p65, indicating that its therapeutic effects on AS may be via inhibition of the UPS.  相似文献   
39.
40.

Background  

Health service policy in the United Kingdom emphasises the importance of self-care by patients with chronic conditions. Written information for patients about their condition is seen as an important aid to help patients look after themselves. From a discourse analysis perspective written texts such as patient information leaflets do not simply describe the reality of a medical condition and its management but by drawing on some sorts of knowledge and evidence rather than others help construct the reality of that condition. This study explored patient information leaflets on osteoarthritis (OA) to see how OA was constructed and to consider the implications for self-care.  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