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   1367596篇
  免费   106217篇
  国内免费   6392篇
耳鼻咽喉   16998篇
儿科学   43481篇
妇产科学   37009篇
基础医学   186482篇
口腔科学   36650篇
临床医学   122516篇
内科学   283735篇
皮肤病学   32322篇
神经病学   112429篇
特种医学   56145篇
外国民族医学   274篇
外科学   213270篇
综合类   31771篇
现状与发展   2篇
一般理论   423篇
预防医学   108209篇
眼科学   28507篇
药学   95410篇
  31篇
中国医学   2306篇
肿瘤学   72235篇
  2018年   13959篇
  2017年   11041篇
  2016年   13216篇
  2015年   14760篇
  2014年   20592篇
  2013年   30610篇
  2012年   37609篇
  2011年   40191篇
  2010年   25140篇
  2009年   24563篇
  2008年   37501篇
  2007年   39964篇
  2006年   41056篇
  2005年   39591篇
  2004年   37737篇
  2003年   36783篇
  2002年   34779篇
  2001年   66226篇
  2000年   68075篇
  1999年   56784篇
  1998年   16899篇
  1997年   15177篇
  1996年   16170篇
  1995年   16346篇
  1994年   15212篇
  1993年   14257篇
  1992年   47221篇
  1991年   45872篇
  1990年   44084篇
  1989年   41908篇
  1988年   38839篇
  1987年   38175篇
  1986年   35944篇
  1985年   34726篇
  1984年   26440篇
  1983年   22196篇
  1982年   13945篇
  1981年   12560篇
  1980年   11812篇
  1979年   23611篇
  1978年   17148篇
  1977年   14471篇
  1976年   13240篇
  1975年   13773篇
  1974年   16153篇
  1973年   15450篇
  1972年   14203篇
  1971年   13065篇
  1970年   11909篇
  1969年   11140篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
991.
Background Oxidative stress and increased inflammation have been reported to be increased in subjects with diabetes and to be involved in the pathogenesis of cardiovascular complications after myocardial infarction (MI). It is well recognized that red wine has antioxidant and anti‐inflammatory activities. We examined the effects of moderate red wine intake on echocardiographic parameters of functional cardiac outcome in addition to inflammatory cytokines and nitrotyrosine (oxidative stress marker), in subjects with diabetes after a first uncomplicated MI. Methods One hundred and fifteen subjects with diabetes who had sustained a first non‐fatal MI were randomized to receive a moderate daily amount of red wine (intervention group) or not (control group). Echocardiographic parameters of ventricular dys‐synchrony, circulating levels of nitrotyrosine, tumour necrosis factor‐α (TNF‐α), interleukin‐6 (IL‐6), interleukin‐18 (IL‐18) and C‐reactive protein (CRP) were investigated at baseline and 12 months after randomization. Results After 1 year of diet intervention, concentrations of nitrotyrosine (P < 0.01), CRP (P < 0.01), TNF‐α (P < 0.01), IL‐6 (P < 0.01) and IL‐18 (P < 0.01) were increased in the control group compared with the intervention group. In addition, myocardial performance index (P < 0.02) was higher, and transmitral Doppler flow (P < 0.05), pulmonary venous flow analysis (P < 0.02) and ejection fraction (P < 0.05) were lower in the control group, indicating ventricular dys‐synchrony. The concentrations of nitrotyrosine, CRP, TNF‐α and IL‐6 were related to echocardiographic parameters of ventricular dys‐synchrony. Conclusions In subjects with diabetes, red wine consumption, taken with meals, significantly reduces oxidative stress and pro‐inflammatory cytokines as well as improving cardiac function after MI. Moderate red wine intake with meals may have a beneficial effect in the prevention of cardiovascular complications after MI in subjects with diabetes.  相似文献   
992.
In the initial stages of tumor formation, overexpression of integrins identifying the RGD sequence (Arg-Gly-Asp) is observed. The aim of the present study was the synthesis and labeling of two novel RGD derivatives, via the precursor [99mTc(H2O)3(CO)3]+, as well as the radiochemical and radiopharmacological evaluation of the labeled products. The labeling led to the formation of a single product in each case (>98%), with noteworthy in vitro stability, fast blood clearance and elimination by the hepatobiliary and the urinary systems.  相似文献   
993.
    
 Müllerian duct regression is first apparent in male pouch young of the tammar wallaby (Macropus eugenii) 6–7 days after birth and, as in eutherian mammals, is characterised by a condensation of the periductal mesenchyme into a whorl around the ductal epithelial cells. A decrease in the density of the extracellular matrix was observed in the region of the whorl. In contrast to eutherian mammals no changes were observed in the mean outer diameter of the Müllerian duct during the early stages of regression. The time at which these mesenchymal changes occur corresponds to the period of Müllerian inhibiting substance secretion in the postnatal tammar testis. Accepted: 25 February 1997  相似文献   
994.
995.
Phonetics, esthetics, function, and comfort form the foundation of a successful dental prosthesis. A review of the mechanics of speech as well as common speech problems encountered with a removable maxillary prosthesis are presented. The use of a palatogram to aid the clinician in the assessment and resolution of speech problems associated with a maxillary denture is demonstrated.  相似文献   
996.
997.
998.
The anticancer agent temozolomide labeled with 13C (8-Carbamoyl-3-13C-methylimidazo-[5,1-d]-1,2,3,5-tetrazin-4-(3H)-one), was noninvasively detected in subcutaneous RIF-1 tumors by a selective cross polarization 13C NMR method, at a field strength of 9.4T. Pharmacokinetics of the drug, at a dose of 150 mg/kg, were determined for intravenous and intraperitoneal modes of administration (three animals per mode). The half-life of the drug in the tumors was approximately 60 min. The uptake and clearance of the drug, however, varied significantly between individual hosts, for both modes of administration. These results demonstrate the feasibility of obtaining pharmacokinetics of anticancer agents for individual tumors without the need for a label that might modify drug activity (e.g., fluorine). The variability of the in vivo measurements, even within the same tumor model, demonstrates the necessity of directly monitoring the tumor to evaluate drug pharmacokinetics.  相似文献   
999.
The Neuro-Bambi     
  相似文献   
1000.
As most of those experiencing traumatic brain injury tend to be young, disabled survivors will be gradually accruing in each locality as each year passes. How many need continuing care a decade after injury? How many need day care, or need help with finding work, or continuing support for carers? 190 patients who had been admitted to two UK regional neurosurgical units on average some 7 years earlier were followed up. With an average age of 29 years these patients stayed in hospital for an average 33 days. At follow-up 23% were classified as having moderate disability or worse on the Glasgow Outcome Scale, including 7.4% who had died subsequent to discharge. Survivors were given a neuropsychological assessment and a socioeconomic interview. Of the survivors, 17% had failed to make a good recovery, but 36% were failing to occupy their time in a meaningful way. Age over 30 at time of injury, not occupied before injury, and above-average length of stay were some of the predictors for failing to occupy time. Quality of life was severely curtailed for those who could not occupy their time, as was the case for their carers. Appropriate counselling, vocational evaluation and family support in the early years following injury may help to improve quality of life for both the head-injured person and their carers.  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