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   177809篇
  免费   50928篇
  国内免费   6824篇
耳鼻咽喉   2285篇
儿科学   5618篇
妇产科学   1350篇
基础医学   25252篇
口腔科学   6694篇
临床医学   25846篇
内科学   35458篇
皮肤病学   8418篇
神经病学   17320篇
特种医学   5915篇
外国民族医学   47篇
外科学   22802篇
综合类   22056篇
现状与发展   26篇
一般理论   33篇
预防医学   13007篇
眼科学   3767篇
药学   16849篇
  155篇
中国医学   8664篇
肿瘤学   13999篇
  2024年   440篇
  2023年   1684篇
  2022年   4173篇
  2021年   6399篇
  2020年   9073篇
  2019年   13754篇
  2018年   13167篇
  2017年   14722篇
  2016年   15002篇
  2015年   16506篇
  2014年   17705篇
  2013年   18084篇
  2012年   12599篇
  2011年   13240篇
  2010年   15627篇
  2009年   10801篇
  2008年   8302篇
  2007年   7058篇
  2006年   6709篇
  2005年   5814篇
  2004年   4291篇
  2003年   4005篇
  2002年   3611篇
  2001年   3053篇
  2000年   2509篇
  1999年   1738篇
  1998年   829篇
  1997年   851篇
  1996年   600篇
  1995年   508篇
  1994年   496篇
  1993年   283篇
  1992年   304篇
  1991年   285篇
  1990年   278篇
  1989年   226篇
  1988年   167篇
  1987年   149篇
  1986年   129篇
  1985年   121篇
  1984年   51篇
  1983年   40篇
  1982年   35篇
  1981年   33篇
  1980年   10篇
  1979年   37篇
  1978年   13篇
  1977年   12篇
  1976年   8篇
  1975年   7篇
排序方式: 共有10000条查询结果,搜索用时 31 毫秒
21.
22.
The authors reviewed the radiographic manifestations of 17 cases of parosteal osteosarcoma, with pathologic correlation in 15. There were two types of parosteal osteosarcoma radiologically. The majority of cases were type I with uniformly dense masses which had regular borders. They often adhered to the cortex and showed no evidence of soft-tissue invasion which correlated with low-grade pathologic malignancy and a relatively benign clinical course. Type II involved the bone, soft-tissue and the medullary cavity. These lesions were poorly differentiated and frequently accompanied by metastatic lesions.
  相似文献   
23.
24.
25.
Abstract – Traumatic dental injuries often occur to the teeth and their supporting tissues and they are the main reasons for emergency visit to a dental clinic. Management of a fracture depends on its position and the extent of root involvement. Horizontal root fractures are not seen frequently and the treatment consists of reduction and long‐term rigid fixation of the coronal segment. The present case demonstrates the successful management of two horizontally fractured maxillary central incisors with a follow‐up period of 9 months.  相似文献   
26.
27.
Aims To measure the prevalence of low high‐density lipoprotein (HDL)‐cholesterol (men < 1.03 mmol/l; women < 1.29 mmol/l) in European Type 2 diabetic patients receiving treatment for dyslipidaemia. Methods The pan‐European Survey of HDL‐cholesterol measured lipids and other cardiovascular risk factors in 3866 patients with Type 2 diabetes and 4436 non‐diabetic patients undergoing treatment for dyslipidaemia in 11 European countries. Results Diabetic patients were more likely to be obese or hypertensive than non‐diabetic patients. Most patients received lifestyle interventions (87%) and/or a statin (89%); treatment patterns were similar between groups. Diabetic patients had [means (SD)] lower HDL‐cholesterol [1.22 (0.37) vs. 1.35 mmol/l (0.44) vs. non‐diabetic patients, P < 0.001] and higher triglycerides [2.32 (2.10) vs. 1.85 mmol/l (1.60), P < 0.001]. More diabetic vs. non‐diabetic patients had low HDL‐cholesterol (45% vs. 30%), high triglycerides (≥ 1.7 mmol/l; 57% vs. 42%) or both (32% vs. 19%). HDL‐cholesterol < 0.9 mmol/l was observed in 18% of diabetic and 12% of non‐diabetic subjects. Differences between diabetic and non‐diabetic groups were slightly greater for women. LDL‐ and total cholesterol were lower in the diabetic group [3.02 (1.05) vs. 3.30 mmol/l (1.14) and 5.12 (1.32) vs. 5.38 mmol/l (1.34), respectively, P < 0.001 for each]. Conclusions Low HDL‐cholesterol is common in diabetes: one in two diabetic women has low HDL‐cholesterol and one diabetic man in four has very low HDL‐cholesterol. Management strategies should include correction of low HDL‐cholesterol to optimize cardiovascular risk in diabetes.  相似文献   
28.
As a part of our ongoing study on Alzheimer's disease (AD) in elderly African Americans, we obtained clinical assessment and apolipoprotein E (ApoE) genotype data on 288 individuals (including 60 with AD). The ApoE σ4 allele frequency was significantly increased in AD patients compared with controls. The age-adjusted odds ratio (OR) for AD in σ4 homozygotes was 4.83 (95% confidence interval [CI], 1.71–13.64) compared with the σ3/σ3 genotype, but the OR for AD with the σ3/σ4 genotype did not reach significance (1.20; 95% CI, 0.58–2.45). These findings suggest that the association between ApoE σ4 and AD is weaker in African Americans than in whites.  相似文献   
29.
中老年人前列腺体积增长的城乡差异   总被引:27,自引:1,他引:26  
为了解国人中年以后前列腺的生长情况及其可能的影响因素,对北京、河北、湖北等地四个社区的城乡居民前列腺体积进行了经腹B超测量。结果表明城区居民的前列腺体积明显大于相应年龄段的农村居民,城区居民的前列腺增长速率比农村居民高二倍。生活环境和饮食习惯的不同可能为其原因之一。  相似文献   
30.
Study Objective . To compare digoxin tablets and liquid-filled capsules with respect to excretion of the drug and its metabolites in urine and feces at steady state. Design . A randomized, crossover trial, each period lasting 3 weeks, with no washout period. Setting . A university hospital. Patients . Six patients, five of whom were elderly, with histories of gastrointestinal disorders, such as hypochlorhydria, intestinal bacterial overgrowth, and inflammatory bowel disease. Interventions . The patients received digoxin once/day in either tablet or capsule form for 3 weeks, and then were switched to the other formulation. Total urinary and fecal excretion from the last 3 days of each regimen were analyzed for the drug and metabolites. Measurements and Main Results . No statistically significant differences were found between tablets and capsules in recovery of digoxin or its metabolites in urine or feces (p=0.05). One subject had a 4-fold increase in urinary drug excretion and 50% decrease in fecal excretion after taking the capsules compared with tablets. Intersubject variability in extent and type of metabolite excretion was greater than intrasubject variability. Conclusions . Fecal analyses may be an accurate way to classify patients as formers of digoxin reduction products.  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